SMITHSONIAN ANNALS OF FLIGHT Number 10 (Final Number in Series) FIRST STEPS TOWARD SPACE Proceedings of the First and Second History Symposia of the International Academy of Astronautics at Belgrade, Yugoslavia, 26 September 1967, and New York, U.S.A., 16 October 1968 EDITED BY Frederick C. Durant III and George S. James *7 NATIONAL AIR AND SPACE MUSEUM M SMITHSONIAN INSTITUTION PRESS SFP 31974 SMITHSONIAN ANNALS OF FLIGHT • NUMBER 10 (Final Number in Series) FIRST STEPS TOWARD SPACE Proceedings of the First and Second History Symposia of the International Academy of Astronautics at Belgrade, Yugoslavia, 26 September 1967, and Mew York, U.S.A., 16 October 1968 EDITED BY Frederick C. Durant \\\ and George S. James NATIONAL AIR AMD SPACE MUSEUM-LIBRARY ISSUH> AUtt 131974 SMITHSONIAN INSTITUTION PRESS City of Washington 1974 A Bibliographic Note The series Smithsonian Annals of Flight terminates with the present issue, number 10. A new series—Smithsonian Studies in Air and Space—will present the future publications of the Smithsonian Institution's National Air and Space Museum. Following is a complete list of the previous titles in the old series: VOLUME 1, NUMBER 1. "The First Nonstop Coast-to-Coast Flight and the Historic T-2 Airplane." Louis S. Casey. 90 pages, 43 figures, appendix, bibliography. Issued 17 December 1964. VOLUME 1, NUMBER 2. "The First Airplane Diesel Engine: Packard Model DR-980 of 1928." Robert B. Meyer. 48 pages, 38 figures, appendix. Issued 30 April 1965. VOLUME 1, NUMBER 3. "The Liberty Engine 1918-1942." Philip S. Dickey III. 110 pages, 20 figures, appendix, bibliography. Issued 10 July 1968. VOLUME 1, NUMBER 4 (end of volume). "Aircraft Propulsion: A Review of the Evolution of Aircraft Piston Engines." C. Fayette Taylor. 134 pages, 72 figures, appendix, bibliography (expanded and arranged by Dr. Richard K. Smith). Issued 29 January 1971. Volume designation terminated; issues hereafter referred to only as "numbers." NUMBER 5. "The Wright Brothers' Engines and Their Design." Leonard S. Hobbs. 71 pages, frontispiece, 17 figures, appendix, bibliography, index. Issued 27 October 1971. NUMBER 6. "Langley's Aero Engine of 1903." Edited by Robert B. Meyer, Jr. 193 pages, frontispiece, 44 figures. Issued 30 March 1971. NUMBER 7. "The Curtiss D-12 Aero Engine." Hugo T. Byttebier. 109 pages, frontispiece, 46 figures. Issued 10 May 1972. NUMBER 8. "Wiley Post, His Winnie Mae, and the World's First Pressure Suit." Stanley R. Mohler and Bobby H. Johnson. 127 pages, 139 figures, appendix. Issued 22 November 1971. NUMBER 9. "Japan's World War II Balloon Bomb Attacks on North America." Robert C. Mikesh. 85 pages, 90 figures, appendixes, bibliography, index. Issued 9 April 1973. OFFICIAL PUBLICATION DATE is handstamped in a limned number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SI PRESS NUMBER 5003. &t f;j■*.•■■.£ Library of Congress cataloging in Publication Data Symposium on the History of Astronautics, 1st, Belgrad, 1967. First steps toward space. (Smithsonian annals of flight, no. 10) Supt. of Docs, no.: SI 9.9: 10. 1. Astronautics—History—Congresses. 2. Rocketry—History—Congresses. I. Durant, Frederick C, 1916- ed. II. James, George S., ed. III. Symposium on the History of Astronautics, 2d, New York, 1968. IV. International Academy of Astronautics. V. Title. VI. Series. TL515.S5 no. 10 [TL787] 629.13'08s [629.4'09] 73-16298 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price $4.00 Stock Number 4705-00011 Preface The fabric of the history of astronautics is woven of stories of individuals and small groups who developed the technologies of rocketry while dreaming of space flight. At least this was true until World War II. Since then, the complexity of guided missiles and rocket-powered aircraft has required much larger enterprises. Official recognition and financial support for such developments were difficult to obtain. Progress was made largely through the personal initiative and dedicated effort of idealists who were deeply convinced that one day man would travel through space. Because much of the detailed history of these technical developments from 1900-1939 has not been available in the published literature, the International Academy of Astronautics of the International Astronautical Federation (IAF) commenced sponsorship of a series of symposia of the history of rocketry and astronautics. The first symposium was held at Belgrade in 1967. Subsequent sym- posia have been held at New York (1968), Mar del Plata (1969), Constance (1970), Brussels (1971), Vienna (1972), and Baku (1973). The proceedings of the first two symposia on the history of rocketry and astronautics form the contents of this volume of the series Smithsonian Annals of Flight. The combination of memoirs and papers from the first and second symposia make it possible to present in one volume new information on the work of leading investigators of astronautics and their associates in the first third of the 20th cen- tury. Thus, the student of the history of astronautics can study independent and parallel efforts which led to the Space Age. "Pre-1939 Memoirs of Astronautics" was the theme of the first IAA History of Astronautics symposium, organized with the cooperation of the International Union of the History and Philosophy of Science, and held on Tuesday, 26 Sep- tember 1967, in Belgrade, Yugoslavia, during the XVIII Congress of the IAF. The philosophy of the organizing committee was to invite living pioneers in astronau- tics so that they might present memoirs. Of the 13 presentations, three were made by the men themselves: O. Lutz, F. J. Malina, and E. A. Steinhoff. The other ten authors were unable to come to Belgrade and their papers were read by other speakers. These papers appeared in Iz istorii astronavtiki i raketnoi tekhniki: Materially XVIII mezhdunarodnogo astronavticheskogo kongressa, Belgrad, 25-29 Sentyavrya 1967 [From the History of Rockets and Astronautics: Materials of the 18th International Astronautical Congress, Belgrade, 25-29 September 1967], pub- lished in Moscow in 1970. The second IAA History of Astronautics Symposium, "New Contributions to the Historical Literature on Rocket Technology and Astronautics, 1909-1939," was held on Wednesday, 16 October 1968, in conjunction with the XIX Congress of the IAF in New York. Of the 14 papers, three memoirs were presented by early investigators: R. Engel, C. D. J. Generales, and S. Herrick. For reference purposes, the papers have been arranged alphabetically by the principal author's last name. The particular symposium at which a paper was presented is indicated by either (1967) or (1968) following the author's name in the table of contents. iii SMITHSONIAN ANNALS OF FLIGHT Through the resources of the National Air and Space Museum's documentary files and library, it has been possible to add original source references for state- ments in a number of the papers. We wish to gratefully acknowledge the assistance and dedication of Frank H. Winter, Research Historian of the National Air and Space Museum, in the prepa- ration of the index. In addition, special appreciation is expressed to the staff editor, John S. Lea, and the Series Production Manager, Charles L. Shaffer, of the Smithsonian Institution Press, for their devoted efforts and assistance throughout the many stages of a uniquely difficult manuscript. It is our hope that this volume will be useful to those persons interested in learning how the first steps were taken to advance the technologies that have opened new avenues of exploration to the Moon and beyond. FCD III GSJ Washington, DC August 1973 Contents Page Preface iii 1. SOME JET PROPULSION FORMULAS OF OVER THIRTY YEARS AGO, by Aldo Bartocci, Italy (1968) 1 2. ROBERT ESNAULT-PELTERIE: SPACE PIONEER, by Lise Blosset, France (1968) 5 3. EARLY ITALIAN ROCKET AND PROPELLANT RESEARCH, by Luigi Crocco, Italy (1967) 33 4. MY THEORETICAL AND EXPERIMENTAL WORK FROM 1930 TO 1939, WHICH HAS ACCELERATED THE DEVELOPMENT OF MULTISTAGE ROCKETS, by Louis Damblanc, France (1967) 49 5. ROBERT H. GODDARD AND THE SMITHSONIAN INSTITUTION, by Frederick C. Durant III, United States (1968) 57 6. GIULIO COSTANZI: ITALIAN SPACE PIONEER, by Antonio Eula, Italy (1968) 71 7. RECOLLECTIONS OF EARLY BIOMEDICAL MOON-MICE INVESTIGATIONS, by Constantine D. J. Generales, Jr., United States (1968) 75 8. THE FOUNDATIONS OF ASTRODYNAMICS, by Samuel Herrick, United States (1968) 81 9. VLADIMIR MANDL: FOUNDING WRITER ON SPACE LAW, by Dr. Vladimir Kopal, Czechoslovakia (1968) 87 10. DEVELOPMENTS IN ROCKET ENGINEERING ACHIEVED BY THE GAS DYNAMICS LABORATORY IN LENINGRAD, by I. I. Kulagin, Soviet Union (1968) 91 11. A HISTORICAL REVIEW OF DEVELOPMENTS IN PROPELLANTS AND MATERIALS FOR ROCKET ENGINES, by O. Lutz, German Federal Republic (1967) ... 103 12. ON THE GALCIT ROCKET RESEARCH PROJECT, 1936-38, by Frank J. Malina, United States (1967) 113 13. MY CONTRIBUTIONS TO ASTRONAUTICS, by Hermann Oberth, German Federal Republic (1967) 129 14. EARLY ROCKET DEVELOPMENTS OF THE AMERICAN ROCKET SOCIETY, by G. Edward Pendray, United States (1967) 141 15. LUDVI'K OCENASEK: CZECH ROCKET EXPERIMENTER, by Rudolph Pesek and Ivo Budil, Czechoslovakia (1968) 157 16. EARLY EXPERIMENTS WITH RAMJET ENGINES IN FLIGHT, by Yu. A. Pobedo- nostsev, Soviet Union (1967) 167 17. FIRST ROCKET AND AIRCRAFT FLIGHT TESTS OF RAMJETS, by Yu. A. Pobedonostsev, Soviet Union (1968) 177 18. ON SOME WORK DONE IN ROCKET TECHNIQUES, 1931-38, by A. I. Polyarny, Soviet Union (1967) 185 v VI SMITHSONIAN ANNALS OF FLIGHT Page 19. S. P. KOROLYEV AND THE DEVELOPMENT OF SOVIET ROCKET ENGINEERING TO 1939, by B. V. Raushenbakh and Yu. V. Biryukov, Soviet Union (1968) 203 20. THE BRITISH INTERPLANETARY SOCIETY'S ASTRONAUTICAL STUDIES, 1937- 39, by H. E. Ross, F.B.I.S., United Kingdom (1967) 209 21. THE DEVELOPMENT OF REGENERATIVELY COOLED LIQUID ROCKET ENGINES IN AUSTRIA AND GERMANY, 1926-42, by Irene Sanger-Bredt and Rolf Engel, German Federal Republic (1968) 217 22. DEVELOPMENT OF WINGED ROCKETS IN THE USSR, 1930-39, Ye. S. Shchetinkov, Soviet Union (1967) 247 23. WILHELM THEODOR UNGE: AN EVALUATION OF HIS CONTRIBUTIONS, by A. Ingemar Skoog, Sweden (1968) 259 24. SOME NEW DATA ON EARLY WORK OF THE SOVIET SCIENTIST-PIONEERS IN ROCKET ENGINEERING, by V. N. Sokolsky, Soviet Union (1968) 269 25. EARLY DEVELOPMENTS IN ROCKET AND SPACECRAFT PERFORMANCE, GUID- ANCE, AND INSTRUMENTATION, by Ernst A. Steinhoff, United States (1967) 277 26. FROM THE HISTORY OF EARLY SOVIET LIQUID-PROPELLANT ROCKETS, by M. K. Tikhonravov, Soviet Union (1967) 287 27. ANNAPOLIS ROCKET MOTOR DEVELOPMENT, 1936-38, by R. C. Truax, United States (1967) 295 Index 303 First Steps Toward Space 1 Some Jet Propulsion Formulas of Over Thirty Years Ago ALDO BARTOCCI, Italy In two articles published in L'Aerotecnica in 1933 and 1934,1 some formulas were presented, together with diagrams concerning the vertical motion of a vehicle having constant acceleration and constant exhaust velocity. It is very interesting to note that the braking effect produced by air on a rocket in vertical mo- tion, calculated by the formulas in the above 1934 articles, coincides perfectly with results presented for the U.S. Navy Neptune (Viking) sounding rocket in a 1949 English publication.2 must be turned off to escape from terrestrial gravity is given by the formula (3) x + r 2wx = 19.62 Applying the formula (3) to some numerical ex- amples, it appears that the initial mass necessary for a given excursion diminishes with increasing exhaust velocity of the jet, thus producing higher acceleration values. The air resistance in kilograms, which has not been taken into consideration in formula (1), is given by the formula: 1000 •*' (2) Vertical Motion by Constant Acceleration The first formulas concern the vertical motion of a space ship with a regulated jet for maintaining a constant acceleration w; with a given constant ex- haust velocity of the jet v; with the earth considered fully spherical with a radius r; and with no allow- ance for air friction. The variation of mass m in the time t is given by the following formula: r 2^7 |_arctan(t|/f) , . ,, w 9.81i / logm = logM0-—t / 1 ° cv CV \ +-„sin 2 arctan where M0 is the initial value of mass and c — 2.30259 is the constant for conversion of a natural logarithm into a common logarithm. The altitude x at which the motor must be turned off for reaching the altitude h is given by the relation 2 ivx = 19.62 r2 (— -j-^—X \x + r h + r / and, in particular, the altitude x at which the motor (4) R = F(V)'d-a* where F(V) is a function depending on the speed of vehicle V; d is the density of the air; a is the diam- eter, in meters, of the transverse section of the vehicle; and i is a shape coefficient. Assuming for the function F(V) the values in function of speed adopted by ballistics, we obtain for air resistance the curves shown in Figure 1 correlating time and acceleration. Vertical Motion by Constant Efflux The second group of formulas concern vertical motion of an unmanned rocket with a constant thrust (constant mass efflux and constant exhaust velocity). Not considering air friction and considering con- stant acceleration of gravity during the operating time of the motor, we have formulas in which M0 is the initial mass of rocket, Mt is the final mass at the end of the combustion, and n is the ratio be- SMITHSONIAN ANNALS OF FLIGHT 0 it 20 SO 40 90 60 10 BO 90 lot 110 Of 130 140 15V FIGURE 1.—Correlation of time and acceleration. The initial velocity V necessary to climb by force of inertia from height h to height H, the latter reached with zero velocity speed is given by V* = 2g0r (8) (_} LA \h + r H+r)' H+r where r is the radius of the earth considered as spherical. From the above formula we can obtain the value of ratio M0 necessary for reaching a previously established altitude H with zero resulting velocity. The rocket reaches this altitude by coasting from altitude h where, at the end of the combustion, it had velocity V. For this calculation a graph has been prepared, shown in Figure 2, for a prompt solution of the problems regarding the rocket's vertical ascension without taking into account the resistance of the air. Regarding the resistance of the air, not considered until now, and expressed by the above formula (8), this can be expressed in function of ratio M0jm where m is the value of the mass at any given time. In Figure 3 are shown a diagram of function F(V)'d of the resistance of the air; a diagram of the relative retarding acceleration WA; and a diagram, with a linear variation, of the rocket's acceleration in the absence of air. (6) tween propulsion force and initial weight of the rocket. The time T corresponding to the end of com- bustion is given by (5) ,= v (l MA The rocket velocity Vt at the end of combustion is given by „ r M0 i/. MtY Vt—v \n— — ( 1 — -r-jT-] f Mt n\ M0/_ The altitude h reached at the end of combustion is given by ht= [MJ. Mt ,\.1 1 /, Mt\ "go (V) NOTES 1. Aldo Bartocci, "Le Escursioni in altezza col motore a reazione," L'Aerotecnica, vol. 13, no. 12 (December 1933), pp. 1646-66; and "II Razzo," L'Aerotecnica, vol. 14, no. 3 (March 1934), pp. 255-66. 2. In a letter to the author, dated 5 July 1949, General G. A. Crocco said: I have indeed been pleased that Professor Eula has informed me that you are the author of the interesting articles pub- lished in 1933, 34, and 38; and I was very glad to have this confirmation authenticated in writing. . I am glad then to tell you that the rate of retardation (drag) introduced by the air in the vertical movement of the rocket, and which today is published by an English Review, the sub- ject of which is the rocket "Neptune" of the U.S. Navy, coincides exactly with that which you designated certainly for the first time, in 1934. The article to which he refers may have been that by C. H. Smith, M. W. Rosen, and J. M. Bridger, "Super Altitude Research Rocket Revealed by Navy," Aviation, June 1947, pp. 40-43.—Ed. NUMBER 10 Ha too K* — — —— ... - —r ... 1 "^^ -^ ^ -4 -4.-1 ^ * ^ J I i ^^ \ ~\_ u IT a t ^^ ^\ N r lo " _J T -£=—^-;<* "^^ ^v \ \ • II ^^ \\ 1 — 1 I ' 1 \ >A \_ , t-—Il — L"___-.-i_lj 1 ^s^ —s A IZ _LX ^^ S. *V ' ' / ' \ > 3 "^ ! —1 —* X s X J Z_ _^ • ; \, \ / / \ 1 [I J -I~ It. J__J VV 1 /_ / \ ^ \ —- / / V\ * ~— 2^—^ \\ , / / ~"~ :■-—-._ JxSt / Kn> fS go »0 6o Jo 40 4o to to FIGURE 2.—Graph for determining relationship of various parameters during vertical ascent of rocket (omitting air resistance). jj „. 3K«/ / g3 ft,. S.M 1" Si. »o / y Vz / / / / / / / ■vA; u y FIGURE 3.—Relationships, with and without air resistance, of rocket acceleration with drag and mass. Robert Esnault-Pelterie: Space Pioneer LISE BLOSSET, France Robert Esnault-Pelterie (REP to his friends) was one of the first pioneers who, by their theoretical and experimental work, foresaw the possibilities of astronautics after those of aviation (Figure 1). Despite his farsightedness and the broad scope of his work on space problems, however, he had to face a profound lack of understanding and over- whelming financial and material difficulties. He received very little support from government and industry, who had no confidence in his projects. FIGURE 1.—Robert Esnault-Pelterie (1881-1957). In the light of the number and value of his origi- nal ideas, what would he not have achieved had he been understood and helped! Son of a textile manufacturer, Robert Esnault- Pelterie, born in Paris on 8 November 1881, took a very lively interest in mechanics from his earliest childhood. At the age of 13 he built by himself an entire electrical network, including lighting, switch- ing panel, and automatic signals, for a miniature steam train he had received as a present.1 At 17 he transformed his small machine shop into a veritable physics and chemistry laboratory and studied wire- less telegraphy.2 His originality was already express- ing itself. Instead of buying or copying, he invented the devices he needed. It was thus that he obtained in 1902 his first patent for a highly sensitive electric relay,3 the same year that he received his science degree at the Sorbonne (botany, general physics, general chemistry). He was then 21 and immediately devoted himself to research in a field that had just been born, aviation. He supplemented his theo- retical work by building and testing his own air- planes, thereby personally checking his results. Aeronautics Let us briefly summarize REP's contributions to aviation. He built his first flying machine in 1904, a tailless biplane glider with fabric-covered airfoils. His glider tests included towing behind an auto (Figure 2) and tests of wing sections and other components mounted above the auto (Figure 3) at speeds up to 60 miles per hour, thereby becoming the first to undertake such direct testing.1 By 1906, the results of these tests enabled him to build the first all-metal monoplane, which he first flew on 19 October 1907.° In order that the engine SMITHSONIAN ANNALS OF FLIGHT !■-*»— FIGURE 2.—Glider designed and constructed by Robert Esnault-Pelterie prior to towing test by auto, 1904. of his plane be as light as possible, he designed it to include an odd number of cylinders axially ar- ranged and a single cam that ensured regular igni- tion in each cylinder at equal intervals.6 This system (Figures 4-5) and the theory of the metallic pro- peller were the subject of a report to the Soci^t£ des Ing^nieurs Civils de France (8 November 1907) which awarded REP its annual grand prize (gold medal).7 Thirty years later, 75 percent of the air- craft built in the world were equipped with engines based on his principle. FIGURE 3.—Test of airplane components from an instrumented automobile at a speed of 100 km/hr, 1905. This 1907 airplane was, in addition, equipped with a large number of devices conceived by him and destined to become classic, notably the "joy- stick" (the single-lever elevator control device in- vented by him), a deformable trihedral landing gear consisting of two wheels without axle, oleo-pneu- matic dampened shock absorbing brakes, and so on.8 From 1908 to 1914, he built numerous airplanes that took part successfully in frequent competitions and broke many records.9 The photograph (Figure he), used for his pilot license no. 4 of the Aero-Club de France, shows him at the controls of the REP-2 monoplane.10 A large number of patents, in addi- tion, show his constant concern for pilot safety: safety belts, speed indicators, parachutes which would release the pilot, double controls for pilot instruction in air-schools, static tests of planes dur- ing their construction, etc.11 Thus he created, a quarter of a century beforehand, all the elements of modern aircraft.12 REP was one of the founders, 29 January 1908, of the Association des Industriels de la Locomotion Aerienne.13 The latter combined, on 22 July 1910, with the Chambre Syndicate des Industries Aero- nautiques, over which he presided for 11 years.14 In 1909 he became president of the executive commit- tee that organized the first international aeronautics exhibition in France, predecessor of the present Salon du Bourget.10 In 1913, he became president of the aviation committee of the Ae'ro-Club de France. NUMBER 10 FIGURE 4.—Exterior view and cross section of 7-cylinder, 35-hp, REP airplane engine, 1907. SMITHSONIAN ANNALS OF FLIGHT FIGURE 5.—a, The 5-cylinder, 65-hp, REP air- plane engine, 1910; b, the 7-cylinder, 90-hp, REP airplane engine, 1911; c, REP at the controls of the REP-2 monoplane. During these years, in which the future of avia- tion became assured, REP foresaw its extension into the conquest of outer space. It has been said (notably by Wernher von Braun in a recent encyclopedia)16 that the great advantage of REP over other space pioneers was that he was renowned during his lifetime.17 This is perhaps true with respect to aviation but absolutely not with respect to astronautics. In fact, as someone once wrote, before World War II, it sufficed for a report to be signed Esnault-Pelterie for it to be filed in the wastebasket by the government officials to whom it was addressed. Astronautics—Historical Summary By 1908 REP had already foreseen the possibility of space travel. This early foresight is documented by Captain F. Ferber in a text dated 26 July 1908 which appeared in his work, "De Crete a crete, de ville a ville, de continent a continent," 18 where he quotes REP's studies. Unknown to REP, on 10 June 1911, Doctor Andre Bing (whom he did not meet until near the end of 1912) was awarded a Belgian patent for an "appa- ratus for exploring upper atmospheric regions how- ever rarefied" in which he discussed the possibility of "traveling beyond the limits of the earth's at- NUMBER 10 mosphere" with "successive rockets" using nuclear energy.19 Shortly thereafter, first in a lecture at Saint Peters- burg (Leningrad; February 1912),20 then in a re- sounding report to the Soci^te Francaise de Physique, in Paris on 15 November 1912, REP pre- sented his studies and conclusions concerning the results of the unlimited lightening of engines and, in the face of sarcasm, for the first time demon- strated theoretically that it was possible for a craft with special design and equipment to travel from the earth to the moon.21 He also predicted the realization of interstellar vehicles once atomic energy had been mastered. As is very often the case, several scientists pursue, at about the same time and without knowing it, original works in the same field. Thus in 1912 (REP mentioned this during a later lecture22) Professor Robert Goddard did theoretical calculations at Princeton University regarding a method of reach- ing extreme altitudes;23 and in 1913 and 1916, at Clark University in Worcester, Massachusetts, he carried out experiments on rockets for exploring the upper atmosphere,24 work based on ideas strik- ingly similar to those of Dr. Bing. In 1912 REP's lecture was published by the Journal de Physique. Because of the elimination of large parts of the text due to page limitations and editing by the secretary of the Journal, the author's thoughts were often hardly understandable. The secretary had in fact been shocked by the contents of the article, whose real purpose REP had pru- dently disguised by an inoffensive title. An English translation of the complete text was distributed at the International Astronautics Congress in 1958 (Amsterdam) as a memorial to REP and is repro- duced as an appendix to this paper. REP deplored the exaggerated condensation of the lecture, which was the cause for an apparent divergence between Goddard's and his own opin- ions concerning the possibility at the time of build- ing vehicles capable of escaping from the earth's gravitation. In fact, Goddard wanted only to send a projectile loaded with powder to the moon and observe its arrival by telescope.25 REP considered the conditions necessary for transporting living beings from one celestial body to another and returning them to the earth; his more pessimistic conclusions were based on considerations of the substantial initial mass required for a rather small final mass, in view of the limited means available at the time. The lecture contains all the theoretical bases of self-propulsion, destroying the myth that rockets need atmospheric support and giving the real equa- tion of motion. Anticipated is the use of auxiliary propulsion for guidance and complete maneuver- ability of rockets. Also contained are calculations of the escape velocity, the phases of a round-trip voy- age to the Moon, and the times, velocities, and durations, of trips to the Moon, Mars, and Venus, as well as thermal problems related notably to the surface facing the sun (polished metal or black surface). This 1912 lecture is the first purely scien- tific study marking the birth of astronautics. While Tsiolkovskiy had the prescience and talent to first suggest, in 1903, rocket propulsion to space,20 REP was the first to develop the equations of the prob- lem and to establish the mathematical theory of interplanetary flight.27 REP is thus the founder of theoretical astronautics. After World War I, he returned, in 1920, to his work on escape velocity,28 but the results, later mentioned by his friend Andre-Louis Hirsch, were not published at the time. On 8 June 1927, he gave a lecture at the Sor- bonne on rocket exploration of the very high atmos- phere and the possibility of interplanetary travel,29 in which he presented quite clearly the theoretical basis showing the importance of the escape velocity and the ratio of initial to final mass, and presented a theory of gas expansion in a convergent-divergent nozzle. Then REP undertook the construction of a strat- ospheric rocket and did numerous tests on liquid fuels, which he preferred to solids for rocket pro- pulsion, but his means were unfortunately quite insufficient. Since he considered liquid oxygen particularly dangerous to handle, he thought it more reasonable to use the explosive liquid tetranitromethane. Un- fortunately, on 9 October 1931, this ultrasensitive explosive caused an accident that cost him four fingers of his left hand.30 Yet the accident did move the administration finally to grant a subsidy to REP, on the initiative of General Ferrie. This sup- port, however, was so limited that it permitted him only to study a few devices but not to undertake their fabrication. After the tetranitromethane acci- dent, REP returned to liquid oxygen and dealt with 10 SMITHSONIAN ANNALS OF FLIGHT the problem of precise and proportional flows of oxygen and fuel.31 As early as 1930, REP studied, with the coopera- tion of Pierre Montagne, the optimal theoretical conditions for reaction engine carburation.32 This study permitted the determination of the mixture ratio of liquid oxygen and petroleum ether to provide optimum performance. In 1932, REP, at his laboratory on Rue des Abondances, in Boulogne-sur-Seine, with Montagne and Salle, attacked the problem of constructing this reaction engine and developed a test stand at Satory which enabled him to study, from 1934 to 1937, the optimum output of his engine by injecting liquid oxygen and petroleum ether into his graphite com- bustion chamber. To deal with problems related to the use of graphite, REP fabricated a nozzle throat from tungsten which he smelted in a high-frequency furnace also specially designed by him for this pur- pose. For these works, REP obtained a small contract from the Direction des ELudes et Fabrications d'Armements, which assigned Ing^nieur General Desmazieres to supervise the execution of the project. In 1937, for dignitaries visiting REP's laboratory, the engine operated 60 seconds without incident, with a thrust of 125 kg. The engine itself met the qualification standard but the subsidy to enable REP to construct the gyroscopic stabilization device that he considered necessary for his rocket was then refused. REP agreed to study a project for a finned rocket, without gyroscopic guidance, but he bap- tized this the "NIC" for "n'importe comment" and subsequently abandoned this project. The outbreak of the 1939 War put an end to REP's activities in astronautics. Projects Scorned by Authorities REP was no doubt the first to recognize the danger of rockets as weapons capable of inter- continental ranges, and this worried him. At first he thought it preferable to remain silent. But the publicity given by the press to his 1927 work, "L'Exploration par fusees de la tres haute atmos- phere et la possibility des voyages interplan^taires," attracted a large correspondence from which he learned of works unknown to him: Die Rakete zu den Planetenraumen by Hermann Oberth (1923); 33 Die Erreichbarkeit der Himmelskorper, by Walter Hohmann (1925);** and Der Vorstoss in den Wel- tenraum, by Max Valier (1925).35 He began to feel that it had become his duty to inform the government of his results, of the poten- tial dangers and the means of developing methods for sending thousands of tons of projectiles several hundred miles in a few hours. Using the calcula- tions he had first made in 1920 with two of his collaborators, Seal and Marcus, he decided to pre- pare a secret report which he sent on 20 May 1928 to his friend, General Ferris, who forwarded it to his chiefs.30 This theoretical report demonstrated that it was already possible to attain a range of 2267 kilometers with an exhaust velocity of 2667 meters per second (REP recognized later that this estimate was optimistic for the time). In addition, REP made a detailed study for the particular case of a rocket of 600-kilometer range, specifying all the mass ratios, and notably the ballistic yield (the ratio between the weight of the necessary propellant and that of the projectile for this range), both for the mixtures of gasoline and nitrogen peroxide that he had taken as examples and for the special solid propellant used by Professor Goddard. The report ended with economic studies compar- ing rocket and aerial bombings and concluded that long-range rockets would be the artillery of the future. After some months, the dossier was returned: it had aroused absolutely no interest! No one at the time considered such works apt to give useful results and the scientist was unable to overcome the inertia of government officials who often systematically ignored anything coming from him. In 1931 the government nevertheless assigned a lieutenant of the technical section of the artillery, J. J. Barre, to work in REP's laboratory. Barre had been collaborating privately with REP since 1927 and had helped with the calculations for the memorandum. This assignment lasted only one year, because it was not considered that "a study of rockets is worthy of the activity of an officer." In spite of this precise and prophetic memorandum, REP did not get the subsidies necessary to carry out the studies he had proposed. The situation was different in Germany, where similar work led to the V-2 rockets. It should nevertheless be noted that in 1931 Andr^-Louis NUMBER 10 11 Hirsch visited Germany, on behalf of REP, to witness the first rocket test at Reinickendorf, near Berlin, and that these tests were in no way held secret, no doubt because the Germans did not yet believe in their military possibilities. Because REP's work was not considered to have useful applications and since the necessary support has always been refused, when the war broke out, REP had, according to his own estimate, gone about 1/100 of the way.37 That is, he had conducted static tests on rocket engines giving thrusts up to 300 kg for 60 seconds: this corresponds to a rocket of a total mass of 100 kg that could reach an alti- tude of 100 km (realized by the Americans after 1945). REP-Hirsch International Astronautics Prize On 1 February 1928, together with Andre-Louis Hirsch, REP founded the REP-Hirsch International Astronautics Prize, awarded up to 1939 to the best original theoretical or experimental work capable of promoting progress in one of the areas per- mitting the realization of interstellar navigation or furthering knowledge in a field related to astro- nautics.38 The term "astronautique" which REP was then introducing into scientific language, had been pronounced for the first time on 26 December 1927 by the French writer, J. H. Rosny, Sr., then President of the "Academie Goncourt" and member of the prize jury (Figure 6).39 Note that the Society Astronomique de France, which was daring enough to sponsor the REP- Hirsch prize, was the first scientific society in the world to recognize that this new science had a future. In the first year, the prize committee received a manuscript from Hermann Oberth, at the time a professor in a small city, and awarded him the prize.40 This enabled him to find a publisher and, when his book was published in 1929, Oberth men- tioned, on the last page, that the Soci£t6 Astro- nomique de France had awarded him the REP- Hirsch prize and said: It is reassuring to see that science and progress suffice to overcome national prejudices. I can think of no better way to thank the Societe Astronomique de France than to pledge myself to work on behalf of science and progress and to judge people only on their personal merits. This paragraph survived in later editions, even during World War II.41 The Russian, Ary Sternfeld, who won the prize in 1934,42 wrote to Andre-Louis Hirsch after the launching of the first satellite to say that REP's books, translated by Rynin,41 had exercised an im- portant influence and that the Soviets had used his mathematical theory of astronautics in their work. The last winner (1939) was Frank Malina, then a young student in California.44 REP's Important Publications on Astronautics Oberth was the first to demonstrate that it was technically possible for rockets to eject their gases at a velocity greater than 4000 meters per second (it was for this work that he was awarded the REP- Hirsch prize). As Oberth had only stated the prin- ciple without mathematical demonstration, REP worked from 1926 to 1930 on the mathematical physics solution, which he published in his 1930 book.45 He also computed the temperature in the combustion chamber and showed that it was much lower than Oberth had thought, because of the increase of specific heats with the temperature. From this he concluded that it would be possible to construct combustion chambers and nozzles of highly refractory materials. Note that REP's theoretical temperature calcula- tions were resoundingly confirmed during the stratospheric ascent of Professor Piccard.46 The basket was a sphere polished on one side and black on the other; the black side was exposed to the sun for a certain time, during which the temperature inside the cabin rose to 39° C.47 REP had predicted a temperature of 42° C. In 1930, REP gathered his results in his major work, L'Astronautique,48 a veritable treatise on space vehicles that served as a basis for all later works on this subject. It is a very profound theo- retical study based on the thorough knowledge of celestial mechanics, astrophysics, and ballistics, as well as physical chemistry and physiology. Nothing in it has yet been invalidated. This book is a basic text for all interested in astronautics. One needs only to scan the chapter titles to see that it is both a scientific and technical document and an encyclopedia of precious practical knowledge: —Rocket Motion in Vacuum and in Air —Density and Composition of the Very High Atmosphere 12 SMITHSONIAN ANNALS OF FLIGHT FIGURE 6.—A meeting of French astronautical pioneers, Paris, 1927. Sitting, from left: Robert Esnault-Pelterie and Andre-Louis Hirsch. Standing, from left: Henri Chretien, inventor of Cinemascope; J. H. Rosny Sr., writer and president, Academic Goncourt; A. Lambert, astrono- mer, Observatoire de Paris (or Professor Ch. Maurain, see note at end of caption); Jean Perrin, Nobel Prize; R. Soreau, President, Societe des Ingenieurs Civil de France; General Ferrie (Head, French Army Signal Corps), member, l'lnstitute de France; Jos. Bethenod, founder, Compagnie Generate de T.S.F.; E. Fichot, president, Societe Astronomique de France; Em. Belot, astronomer. Note: this individual is identified as A. Lambert on page 217 of Andrew G. Haley, Rocketry and Space Exploration (New York: D. Van Nostrand Company, 1958), and as Ch. Maurain in a caption supplied by Andre-Louis Hirsch to Woodford A. Heflin in 1960 and published in "Astronautics," American Speech, vol. 36, October 1961, pp. 169-174.—Ed. —Expansion of Combination Gases Through a Nozzle —Combustion in a Chamber —Possible Use of Rockets (high altitude exploration, launch- ing projectiles to the moon, high-speed travel around the earth, and travel through the atmosphere) —Interplanetary Travel (with sections on the conditions under which trips around the moon will be carried out, the design of the spaceship, guidance, navigation and piloting devices, the conditions for habitation). For these last points, REP states that the spaceship could be^ filled with pure oxygen, which would reduce the pressure to about a tenth that of the atmosphere and would also serve to substantially reduce leakages. In the section on the guidance of a spaceship, we already find the principle of stabilization by "three small electric motors each one with a flywheel of sufficient moment of inertia and placed with their axes at right angles." REP also suggests that the spaceship, for its re- turn to earth, be turned and braked first by its own engines (today's retrorockets) and then by the use of a parachute. In May 1934, REP published a supplement to his 1930 book in which he presented the practical con- ditions and the advantages of interplanetary trips.49 This work included a study of rocket motion (velocity, trajectories as a function of the combus- tion regimes and masses); a new study of combus- tion gas expansion nozzles; combustion thermo- dynamics (referring to the thermochemical studies of Pierre Montagne, for which the latter was awarded the REP-Hirsch prize in 1931); prophetic considerations on nuclear propulsion; and the use of radioactive elements (neutrons and atomic fission had just been discovered) and of atomic hydrogen (REP was thus the first to consider using free radicals to ensure the maximum utilization of available energy for propulsion). NUMBER 10 13 In addition to a study of orbital paths (corre- sponding to our transfer orbits), this work includes considerations on the application of relativity to energy radiation (REP anticipated photonic pro- pulsion, study of which has been undertaken re- cently in some countries). The principle of multistage rockets and the cal- culations of mass ratios presented by REP stimu- lated the work of Louis Damblanc, who in 1936 was awarded a patent for "self-driven projectiles whose propulsive charge is distributed in several combustion stages along the axis of the rocket." 50 REP also foresaw the advantage of rockets for the study of the aurora borealis, which is the purpose of many current sounding rockets. After the publication of the supplement to his book, REP was awarded his second annual Grand Prize by the Societe des Ing^nieurs Civils de France. On 22 June 1936, he became a member of the Acaddmie des Sciences in the division "applications de la science a l'industrie." 51 Some Experimental Works Let us review some of REP:s experimental works that enabled him to solve certain problems in an original way (we owe the details of paragraphs 1—4 to Ing£nieur General J.-J. Barre, who sent us copies of certain of REP's reports, the originals of which have been destroyed). 1. Method of injecting fuel and oxidizer into the combustion chamber.—REP first tried using a de- vice including volumetric pumps driven by a sort of gas turbine turned by part of the jet from the nozzle. This design was abandoned because of the difficulties due to pump lubrication and the poor behavior of the liquid-oxygen fittings. He then used pressurized tanks for feeding the fuel and oxidizer. This system worked by the pressure of an inert gas on the fuel and by the action of a heater that raised the pressure of the oxygen and vaporized part of it. Figure 7 shows a particularly original device used by REP's team. It is based on the fact that the vapor pressure of liquid argon is 31.5 hpz at 140° K, while the vapor pressure of liquid oxygen at this temperature is 25 hpz. A bypass (7) operates at the pressure of the liquid oxygen tank (3) and allows the petroleum ether to pass at a rate sufficient to maintain the pressure at 25 hpz, taking into ac- count the heat given off by the liquid oxygen to the FIGURE 7.—Device for injecting fuel and oxidizer into the combustion chamber. 1, Argon tank. 2, Coil exchanger. 3, Liquid oxygen tank. 4, Release valve. 5, Petroleum ether tank. 6, Pressure gauge. 7, Heating by-pass regulator. 8, Petroleum ether outlet. 9, Liquid oxygen outlet. argon contained in tank (1). Relief valve (4), in which the argon vapor is expanded at 25 hpz, forces the petroleum ether from the tank (5) to- wards the jets 52 either directly or through exchange coil (2). For the static tests at Satory (see 5, below), com- pressed nitrogen was used to feed the fuel through a relief valve. This device operated very safely, provided the regulators were defrosted when neces- sary. The major advantage was the remarkably low dead weight, but it was not entirely satisfactory when used for cold and dense gases, the mass of which tends to become quite substantial. 2. Vibrating volumetric feed regulator.—REP then conceived of a vibrating volumetric feed regu- lator to control the liquid flow. Figure 8 shows the working of a device designed according to the prin- ciple of a double pendulum. The liquid leaves tank (K) by two cylinders (C) and the ports of the slide- valves (T) connected to pistons (P) by springs. The slide-valves (T) were fixed to the cylinder frame by springs. The entire system vibrated in resonance with tank (K), whose vibrations could be tuned to those of the piston/slide-valve assembly, by means of closed tube (A). The liquid flow was thus pro- vided by equal and synchronous volume. This device worked quite well during its first water test. 14 SMITHSONIAN ANNALS OF FLIGHT FIGURE 8.—Vibrating volumetric feed regulator. 3. Constant pressure drop jet.—This jet was intended to ensure a correct mixture ratio with con- stant pressure drop whatever the liquid viscosity. Figure 9 shows the inner surface of the jet, which is grooved. When the depth (b) of these grooves is equal to the distance (a) between them, the flow is independent of the viscosity of the fluid. Naturally, this arrangement increases the pressure drop be- tween the tank and the combustion chamber. 4. Means of lightening tanks.—Light alloys proved to be particularly good material for liquid oxygen tanks because their mechanical character- istics are better at very low temperatures. Since it was not possible at this time to weld such alloys, REP designed tanks of duralumin, using thin rolled-up sheets and bonding successive layers to- gether (Figure 10). Because of the low quality of the available adhesives, he did not continue his efforts to perfect this method at the time, but the idea was adopted very much later in other coun- tries. 5. Firing tests at Satory.—A test stand was built at Satory in 1932. It was used for engines delivering thrusts up to 100 kg and later up to 300 kg. Exhaust velocities of 2400 m/sec were attained in 1936. Figure 11 shows this apparatus in detail. The compartment on the left housed the petroleum ether tank; that in the center, the engine being tested; and that on the right, the liquid-oxygen tank. Each of the tanks was mounted on a recording balance. The engine, with its jet directed downward, was suspended from a dynamometer having a power- ful vibration damper that from the beginning worked as REP had calculated. The successive tests enabled the measurement of the time, the pro- pellant flow, the tank pressures, combustion cham- ber pressure, pressure at the nozzle throat, the engine thrust, and the inlet and outlet coolant temperatures. These measurements were executed automatically in the proper sequence by a mechan- ical timer invented by REP. It should be noted that this assembly worked correctly from the beginning. It was necessary to add only an electric heater in order to pressurize the oxygen tank. For cooling REP at first used water. A study of cooling by liquid oxygen was under- taken next and tests were conducted on 15 October, 3 and 16 December 1936.53 77/ W FIGURE 9.—Inner surface of injector, showing grooves. FIGURE 10.—Rolled and adhesive-bonded sheets for the manufacture of tanks. NUMBER 10 15 FIGURE 11.—Experimental facility at Satory for static-test firing of rocket engines. Figure 12 shows the system for cooling the nozzle by circulation of the liquid oxygen before its intro- duction into the thrust chamber. The latter was made of duraluminum and contained a block of pure copper into which were screwed six pure copper premixing chambers. The latter were equipped with four rings of jet holes. The nozzle was made entirely of pure copper, and its outer surface had longitudinal 30° grooves which, while doubling the surface wetted by the oxygen, provided sufficient passage for the latter even in the case that the nozzle, when expanding to regulate the thickness of the cooling sheet of liquid oxygen would touch the outer ring (A). The fuel arrived under pressure at B and, pass- ing through the circular feeder (C), escaped by 290 small triangular slits cut 0.5 mm into the upper part of ring D, and wet the external surface of the nozzle. The flow around the nozzle is con- trolled by ring A, whose cylindrical bore was threaded so as to provide a rough surface that en- sured a constant pressure drop. The dimensions of the oxygen passages, that is, the relative positions of the nozzle and rings A and D, had been previ- ously adjusted according to the results of water-flow tests. None of the three tests was successful, and REP abandoned the idea of cooling by liquid oxygen. The reason for his efforts to cool the nozzles in this way was that he feared it would not be possible to operate without cooling. 6. Uncooled refractory nozzles.—At the end of 1936, REP began to work on nozzles made of ultra- refractory materials. For this purpose he built an electric furnace of his own design. After many diffi- culties due to the outdated equipment he was obliged to use because of lack of money, and after many experiments64 he managed to make con- vergent parts of nozzles to the following dimen- sions: a cylinder 50 mm in diameter and 20 mm thick having, along its axis, a hole of which the diameter converged from 35 mm at the entrance to 17 mm at the throat. At that time his tests nor- mally lasted 60 seconds. In order to fabricate with this furnace the nozzles needed, he had in vain asked the Caisse Nationale des Recherches Scienti- 16 SMITHSONIAN ANNALS OF FLIGHT FIGURE 12.—Diagram showing method of cooling rocket nozzle with liquid oxygen, December, 1936. fiques for a grant that would allow him to buy a secondhand 32,000 cycle alternator for 6000 francs of the time, as well as various parts for measurement instruments. In spite of the crippling conditions under which he was obliged to work, his efforts to improve the material for his furnace nevertheless enabled him to construct an electric furnace of highly original design, which he named "four- fronde" and for which he used centrifugal force to increase the compactness of the ceramic material during the treatment. It is noteworthy that he also experimented on throatless nozzles, the cylindrical chamber opening directly into the diverging cone. 7. Rocket guidance.—Some of the devices in- vented by REP were used in the V-2 rockets and in the American Viking rockets derived from them. An example is the gimbaled nozzle proposed by REP in 1927. REP described this nozzle as "con- nected to the control stick by a system in such a way that the pilot would have only to make simple instinctive movements. It would even be possible to control the rocket automatically by means of a system of pendulums." This idea was applied in the V-2 integrating-accelerometer that guided the rocket by controlling the jet deflectors. In fact this accelerometer is composed of a gyroscopic pendu- lum mounted on gimbals. Other Technical and Scientific Fields In addition to his work on aviation and astro- nautics, REP applied his exceptional vision to many other fields—metallurgy, electricity, mag- netism, viscosity, compressibility of liquids, and thermodynamics. He received more than 200 in- ventor's patents55 and built many devices involving new principles, such as explosion and combustion engines, combustion turbines, mechanical and hy- draulic gear systems, automobile suspensions, elec- tromagnetic devices, hardness measuring instru- ments for metals,56 and medical apparatus for electrical shock treatments. His ballistic engine, on which he worked from 1916 to 1921 (the energy of the gas was transmitted to a liquid acting on a hydraulic tank) corresponds to the first idea of hydraulic power transmission which is only now beginning to be applied57 (e.g., the German Klatte transmission). In 1915, as a forerunner in yet another field, he carried out extensive research on the use of tidal energy in the Straits of Dover.58 It is noteworthy that REP never hesitated to go beyond the limits of his own field as soon as he was hampered by a lack of theoretical bases, nor did he hesitate to carry out a number of basic research projects, some of great value. For example, in his astronautics work, he made careful study of a great many ideas relating to dimensional analysis, i.e., the means of determining the form of equations associating certain values. In fact, in 1933, his work on rockets using oxygen and liquid fuels posed the problems of designing a small injector for a rocket engine of some 20,000 nominal horsepower that would weigh no more than 2.5 kg and occupy a small volume. REP thus found himself faced with a flow problem where the equations of hydrodynamics were not easy to apply. The only solution was to carry out a series of NUMBER 10 17 measurements and to complement his experiments by theoretical study within the scope of dimen- sional analysis. Since he was unable to find the necessary information in existing publications, he undertook the work himself. His findings, which he communicated to the Acad^mie des Sciences in 1933, included notably the discovery of a particular type of constant pressure drop flow ("isozemique") that, as demonstrated by dimensional analysis, is independent of viscosity.59 The tests described above with petroleum ether and liquid oxygen, using orifices determined by these calculations, con- firmed his forecasts exactly. The final result was the publication at Lausanne in 1948 of his book on dimensional analysis, VAnalyse dimensionnelle, the preliminary manu- script of which was written between September 1945 and April 1946.60 Since we are conducting a symposium on the history of astronautics, I should like to draw atten- tion to the fact that in an appendix to this book, REP had proposed creating in each faculty a Chair in the History of Science for the purpose of promot- ing a study of the errors in judgment which have had to be overcome in order to make progress pos- sible and for comparing the various hypotheses that had to be abandoned with those that have survived; for he said that knowledge of the reasons for these choices is frequently much more useful in the train- ing of a scientific mind than the study of texts in their definitive form, which leaves the student under the illusion that "all came about by itself." Last Years After the war, REP, who had retired to Switzer- land unknown and misunderstood, abandoned space research. This extremely unfortunate decision was a great loss for astronautics, particularly since almost all his unpublished work was lost. Moreover, many documents in the possession of certain col- leagues had to be destroyed at the time our country was occupied. However, on 9 May 1947, in a lecture given at the Aero-Club de France, REP returned to the results of his calculations and conclusions concerning the mixtures previously studied (solid propellants and petroleum ether/liquid oxygen) and added to these mixtures of liquid hydrogen/liquid oxygen and uranium 235 and plutonium.61 FIGURE 13.—REP's apartment at 43 Boulevard Lannes, in Paris, after attachment of his furniture by the Tax Department. In his last years, REP experienced many trying days. He who could have made a fortune thanks to his inventions, was harassed by the tax department and his furniture was attached (Figure 13)—this on top of the indifference, the lack of understanding, and the sarcasm he had suffered all his life. After participating in the exciting development of aviation, REP, as a space pioneer had the some- what bitter consolation, before his death on 6 De- cember 1957, of seeing his ideas confirmed abroad, first by the V-2 and later by the launching of the first earth satellite, Sputnik I, in the USSR. On the day of his death, a Vanguard rocket was launched at Cape Canaveral (now Cape Kennedy) like a salute in his honor. After looking into the laborious life of this in- genious pioneer, we salute the memory of this uni- versal man, hardly knowing what to praise the most —the researcher's rich imagination; the theorti- cian's rigorous reasoning; the experimentalist's capability, boldness, and intrepidity; or the engi- neer's concern for perfection. I should like to express my appreciation to all those who helped me in my library research on Robert Esnault-Pelterie and in particular, Gaston Palewski, former Minister of Scientific Research; Ingenieur General J.-J. Barre; Pierre Montagne; Alexandre Ananoff; and George S. James. NOTES The author of this paper, Lise Blosset, is (1973) Directeur Adjoint, Charge de Mission aupres du Directeur General Centre National d'Ltudes Spatiales, 129 rue de l'Universite, Paris, France.—Ed. 1. Robert Esnault-Pelterie, Vie et travaux scientifiques (Orleans, France: Henri Tessier, 1931), pp. 3-5 (hereafter cited as REP, Vie et travaux).—Ed. 2. REP, Vie et travaux, pp. 5-6.—Ed. 1. 18 SMITHSONIAN ANNALS OF FLIGHT 3. French Patent 318,667, 13 February 1902, Relais sensible dc telegraphic sans fil.—Ed. 4. The result of these gliding and automobile-towed glider tests, conducted near Calais, and the flight performance measurements of components mounted above an automobile, during high speed runs between Vierson and Salbris (South of Orleans) were reported in: REP, "Experiences d'aviation, executees en 1904, en verification dc celles des freres Wright," L'Aerophile, vol. 13, June 1905, pp. 132-138 (presented at a conference of the Aero Club of France on 5 January 1905); REP, "Communication, faite a la Societe Francaise de Navigation Aerienne par M. Robert Esnault-Pelterie," L'Aeronaute, vol. 40, February 1907, pp. 31-40, and March 1907, pp. 61-72 (presented on 24 January 1907); REP, Vie et travaux, pp. 7-12, 47-59.—Ed. 5. "L'Aeroplane et le moteur extra-leger Esnault-Pelterie," L'Aerophile, vol. 15, April 1907, pp. 100-101 (editorial com- ments and a letter from REP, dated 22 March 1907 describing research); A. de Masfrand, "Premiers essais publics de l'aeroplane Esnault-Pelterie," L'Aerophile, vol. 15, October 1907, pp. 289-91; "M. Esnault-Pelterie's Experiments," The Automotor Journal, vol. 12, 26 October 1907, p. 1516; "The Esnault-Pelterie Flying Machine," The Automotor Journal, vol. 12, 2 November 1907, pp. 1533-34; 'Portraits d'aviateurs contemporains" and REP, "L'Aeroplane et le moteur extra- leger Robert Esnault-Pelterie," L'Aerophile, vol. 15, December 1907, cover and pp. 330-32; "Progress of Mechanical Flight, Individual Performance to Date," Flight, vol. 1, 2 January 1909, p. 12; REP, Vie et travaux, pp. 12-16.—Ed. 6. "The 'R.E.P.' Aerial Motor—A Striking Design," The Automotor Journal, vol. 12, 2 November 1907, pp. 1534-35, and "The 7-Cyl. 'R.E.P.' Airship Motor," 30 November 1907, p. 1719; REP, "Le Moteur R.E.P. sept cylindres," La Revue de I'Aviation, vol. 2, 15 November 1907, pp. 5-7; W. F. Bradley, "Advance in Aeronautical Motor Building," The Automobile, 13 August 1908, pp. 225-28; "Aeroplane Pro- pellers; Table of Propellers at the Paris Salon," Flight, vol. 1, 9 January 1909, pp. 22-23; "The First Paris Aeronautical Salon; Engines for Airplanes," Flight, vol. 1, 16 January 1909, pp. 33-35, and 23 January 1909, p. 47; L. Lagrange, "L'Aero- plane REP et les moteurs REP," L'Aerophile, vol. 17, 15 January 1909, pp. 33-37, xi; H. Kromer, "Motor R. Esnault- Pelterie," Deutsche Zeitschrift fur Luftschiffahrt, 30 June 1909, pp. 558-60; Rapport officiel sur la premiere Exposition Internationale de Locomotion Airienne (Paris: Librairie Aeronautique, 1910), pp. 45-47, 48, 59-60; "Les Moteurs d'aviation; le nouveaux moteur REP (50-60 chx), "L'Aero- phile, vol. 18, 1 September 1910, pp. 401-02; "Les Moteurs a l'Exposition [illus.], L'Aerophile, vol. 18, 15 November 1910, p. 515; "The Vickers-R.E.P. Engines," The Aeroplane, vol. 1, 21 June 1911, pp. 50, 70; Paul Pouchet, "Le Nouveau Moteur 'REP'; types 50/60 et 40/50 chx a 5 cylindres," L'Aerophile, vol. 19, 15 April 1911, pp. 177-179; Alex Dumas, "Les Moteurs et les helices," L'Aerophile, vol. 20, 1 January 1912, pp. 12-14.—Ed. 7. "L'Aviation aux ingenieurs civils; M. Robert Esnault- Pelterie laureat de la Societe des Ingenieurs Civils," L'Aero- phile, vol. 16, 1 July 1908, p. 255; REP, Vie et travaux, pp. 12-14, pp. 61-86 (reprint of 8 November 1907 lecture). —Ed. 8. A. Dc Masfrand, "Premiers essais publics de l'aeroplane Esnault-Pelterie," L'Aerophile, vol. 15, October 1907, pp. 289- 91; REP, "L'Aeroplane et le moteur extra-leger Robert Esnault-Pelterie," L'Aerophile, vol. 15, December 1907, pp. 330-32; REP, Vie et Travaux, pp. 12-17. Legal acknowledg- ment of Esnault-Pelterie's invention of the "manche a balai" (joy-stick) came, in France and other countries, only after many years of court litigation; see "Systems of Con- trol," Flight, vol. 1, 2 January 1909, pp. 9-10; "The Esnault- Pelterie 'Joy-Stick' Bombshell," and "The R.E.P. Litigation in France," Flight, vol. 12, 12 August 1920, pp. 876, 878; "Un Grand Conflit industriel," and Charles Weismann, "Les Proces du manche a balai," L'Aerophile, vol. 28, 15 August 1920, pp. 251-52; "The R.E.P. Litigation," Flight, vol. 12, 19 August 1920, p. 915; REP, "Les Proces du manche a balai," L'Aerophile, vol. 28, 15 September 1920, p. 268; C. Weismann, "Les Questions du manche a balai," L'Aerophile, vol. 28, 15 October 1920, pp. 313-14; "The Joy Stick Liti- gation," Flight, vol. 12, 28 October 1920, p. 1136; "L'Affaire Esnault-Pelterie en Cour d'Appel," L'Aerophile, vol. 30, 15 November 1922, p. 339, and 15 December 1922, p. xix; and L'Aerophile, vol. 31, 15 January 1923, pp. 23-24; 15 February 1923, pp, xix-xx; 15 March 1923, pp. 89-90; 15 April 1923, pp. 116-17; 15 May 1923, pp. 112-13; 15 July 1923, pp. 220-22; "The 'Joy-Stick' Action," Flight, vol. 15, 24 May 1923, p. 280; "The 'Joy-Stick' Action," and "The French 'Manche a Balai' Action," Flight, vol. 15, 31 May 1923, pp. 288, 297; "The 'Joy-Stick' Claim," Aeroplane, vol. 24, 30 May 1923, p. 404; and "Joy-Stick," Time, vol. 18, 5 October 1931, pp. 30 and 32.—Ed. 9. Georges Blanchet, "Experiences de M. R. Esnault-Pelterie, le nouvel aeroplane R.E.P.—a 30 metres de hauteur—les records du 'monoplan,'" L'Aerophile, vol. 16, 15 June 1908, p. 226; Fred T. Jane, All the World's Air Ships (London: Sampson Low, Marston & Co., Ltd., 1909) pp. 121-22, 347, 355; "R.E.P. (No. 2)," Flight, vol. 1, 9 January 1909, p. 19; L. Lagrance, "L'Aeroplane REP et les moteurs REP," L'Aerophile, vol. 17, 15 January 1909, pp. 33-37 and xi; Oiseau, "Impressions of the Paris Show," Flight, vol. 2, 22 October 1910, p. 862, and 29 October 1910, p. 880; Jane, All the World's Airships (London, 1910), pp. iii, iv, 129, 164, 424, 437, 441, 446, 457, 463; "The Last Day," and "Laurens Wins the Coupe Deperdussin," Flight, vol. 3, 7 January 1911, pp. 8, 17; "Pierre Marie Bournique, sur 'REP,' vole 530 kilometres et etablit les nouveaux records du monde a partir de 250 kilometers," L'Aerophile, vol. 19, 15 January 1911, 28; "Latest Official World's Records," Flight, vol. 3, 21 January 1911, p. 57; Mervyn O'Gorman, "Problems Re- lating to Aircraft," Flight, vol. 3, 25 March 1911, p. 266; Paul Pouchet, "Les Aeroplanes REP et le moteur REP, 5 cylindres," L'Adrophile, vol. 19, 15 April 1911, p. 173-79; "The Latest R.E.P. Racing Monoplane, Le Poussin," Flight, vol 3, 13 May 1911, p. 425; "Gilbert's R.E.P., the only machine to go through [the European Circuit] with the same engine from start to finish," The Aeroplane, vol. 1, 13 July 1911, p. 127; "Aero- planes REP," L'Aerophile, vol. 19, 1 November 1911, pp. 504-05; "The R.E.P. stand at the Paris Air Show, and the New 90 h.p. 7 cyl. R.E.P. motor," Flight, vol. 3, 30 Decem- ber 1911, p. 1135-36; Jane, All the World's Aircraft, 1912, pp. 149, 178, 347, 363; "World's Flying Records," Aero 8. NUMBER 10 19 Club of America Bulletin, vol. 1, June 1912, p. 17; "The Latest R.E.P. Monoplane," Flight, vol. 4, 30 September 1912, p. 854; "The 80 hp R.E.P. hydromonoplane," Flight, vol. 4, 9 November 1912, p. 1028; Jane, All the World's Aircraft, 1913, pp. 77, 100, lib, 7c, Id, 25d; "R.E.P. Redivivus," The Aeroplane, vol. 4, 11 December 1913, p. 634; Jane, All the World's Aircraft, 1914, pp. 72, 92, lib, 16d; "R.E.P.," Flight, vol. 6, 10 January 1914, p. 33; Jane, All the World's Aircraft, 1916, pp. 123 and 15b; "Le Concours de la securite," I'Aero- phile, vol. 22, 1 July 1914, pp. 304-305; Owen Thetford, British Naval Aircraft, 1912-58 (London: Putnam, 1958) p. 382 (R.E.P. Parasol). A list of the records established by REP airplanes is presented in Lucien Marchis, Vingt cinq ans d'aeronautique francaise (Paris: edite par la Chambre Syndicate des Industries Aeronautiques, 1934), vol. 1 (of 3), p. 194.—Ed. 10. "Bulletin officiel de l'Aero-Club de France," L'Aero- phile, vol. 17, 15 January 1909, p. 43; "Official Pilots," Flight, vol. 1, 16 January 1909, p. 39; "The Trials of a Pilot, Being Some Account of the Experiences of M. Esnault-Pelterie and Others in the Air," Flight, vol. 1, 30 January 1909, pp. 60-61; "The First Aviation Pilots to Whom the Aero Club of France Have Granted Certificates and Their Credentials," Flight, vol. 1, 6 March 1909, p. 131.—Ed. 11. "The R.E.P. Belt with Quick Detachment Device," The Aeroplane, vol. 1, 21 June 1911, p. 68; Henry Woodhouse "The R.E.P. Safety Belt," and "The R.E.P. Wings Supporting a Load of 6,250 Kilograms of Sand," (in "What is Being Done to Make Aviation Safe in Europe"), Aero Club of America Bulletin, vol. 1, August 1912, pp. 15-16. His aviation safety procedures and a list of his aviation patents appear in REP, Vie et Travaux, pp. 14-19, 98-100.—Ed. 12. REP, Quelques reseignements pratiques sur I'aviation (Paris: Librairie Aeronautique, 1912).—Ed. 13. "La Chambre Syndicate des Industries Aeronautiques," L'Aerophile, vol. 16, 1 March 1908, p. 84.—Ed. 14. "French Trade Societies Formally Amalgamated," Flight, vol. 2, 30 July 1910, p. 601.—Ed. 15. Philos, "Ire Exposition Internationale de Locomotion Aerienne, organisee par l'Association des Industriels de la Locomotion Aerienne sous le patronage de l'Aero-Club de France," L'Aerophile, vol. 17, 1 October 1909, pp. 433-34 — Ed. 16. Wernher von Braun and Frederick I. Ordway III, His- toire Mondiale De'Astronautique (Larousse, Paris-Match, 1968).—Ed. 17. "Esnault-Pelterie etait le plus ecoute des quatre pionniers de l'astronautique, car il fut le seul a etre celebre de son vivant. II a eu, comme Oberth, la joie de voir ses reves entrer dans la voie des realisations, puisqu'il est mort apres le lancement des deux premiers 'Spoutnik,' " Histoire Mondiale d'Astronautique, p. 79.—Ed. 18. "From Crest to Crest, From City to City, From Con- tinent to Continent," in L"Aviation, ses Debuts—son develop- ment (Paris, Nancy: Berger-Levrault & Cie, 1908), p. 161. REP's aviation achievements also are mentioned on pp. 132- 34.—Ed. 19. Belgian patent 236,377, 10 June 1911, A Device for Studying the Upper Atmosphere.—Ed. 20. REP, L'Astronautique (Paris: A. Lahure, 1930), p. 20, footnote 3.—Ed. 21. REP, "Consideration sur les rcsultats de l'allcgement indefini des moteurs [Considerations concerning the results of the indefinite lightening of motors] (Fontenay-aux-Roses: L. Bcllcnand, 1916). Presented to the Societe Francaise de Physique on 15 November 1912 and originally published in Journal de Physique, ser. 5, vol. 3, March 1913, pp. 218-30. Sec Appendix for a complete translation of this work. 22. REP, "L'Exploration par fusees de la tres haute atmos- phere et la possibility des voyages interplanetaires," [Rocket Exploration of the Very High Atmosphere and the Possi- bility of Interplanetary Travel] (Paris: Societe Astronomique de France, 1928). Lecture given before the Society on 8 June 1927.—Ed. 23. Robert H. Goddard, "A Method of Reaching Extreme Altitudes," Smithsonian Miscellaneous Collections, vol. 72, no. 2, December 1919, Preface and pp. 5-11. REP and Goddard exchanged an interesting series of letters dating back to REP's first letter on 31 March 1920. The plans of both pioneers to meet each other were never fulfilled, see The Papers of Robert H. Goddard, edited by Esther C. Goddard and G. Edward Pendray (New York: McGraw-Hill Book Company, 1970), vol. 1, pp. 432, 436-37, 442, 445, 448-49, 450, and vol. 2, pp. 646-47, 651, 931, 938, 940, 947, 999—Ed. 24. Goddard, "A Method of Reaching Extreme Altitudes," pp. 12-54.—Ed. 25. Op. cit., note 24, pp. 55-57, 67-68 (notes 19-21).—Ed. 26. Konstantin Eduardovich Tsiolkovskiy, "Issledovanie mirovykh prostranstv reaktivnymi priborami" [Investigation of Space by Means of Reaction Devices], Nauchnoye obozreniye [Science Review], no. 5, 1903.—Ed. 27. Op. cit., note 1. 28. Op. cit., note 20, p. 20.—Ed. 29. Op. cit., note 22. 30. REP, "De L'Aeronautique a l'astronautique," in: Quinze ans d'aeronautique francaise, 1932-1947 (edite par l'Union Syndicale des Industries Aeronautiques, 1949), p. 17.—Ed. 31. Op. cit., note 30. 32. In current American usage, the term carburetion has been replaced by the term injection for the process of in- jecting, atomizing, and mixing the propellants of a liquid- fueled rocket engine.—Ed. 33. [The Rocket Into Interplanetary Space], Munich-Berlin: R. Oldenbourg, 1923. 34. [Accessibility of Celestial Bodies], Munich: R. Olden- bourg, 1924. 35. [Moving Forward into Outer Space], Munich: R. Olden- bourg, 1924. 36. REP, Rapport a Monsieur le General Ferrie, (Paris, 20 May 1928, unpublished. 37. The appraisal given by the Germans was: "Esnault- Pelterie experimented with liquid oxygen and gasoline as propellants. He worked there (near Paris) with more or less success, until the War broke out. When the Germans later investigated his facilities, they came to the conclusion that it would have taken him several years to accomplish the first convincing result." Walter R. Dornberger, "European Rock- etry After World War I," Journal of the British Inter- planetary Society, vol. 13, no. 5 (September 1954), pp. 245-55, 262; and "European Rocketry After World War I," in Reali- 21. 20 SMITHSONIAN ANNALS OF FLIGHT ties of Space Flight, edited by L. J. Carter (London: Putnam, 1957), p. 390.—Ed. 38. E. Fichot, "Le Prix REP-Hirsch' et les problems de l'astronautique," Bulletin de la Societe Astronotnique de France, vol. 42, February 1928, pp. 57-59; see editorial intro- duction to REP, "La Navigation intersiderale on astro- nautique," L'Aerophile, vol. 36, 15 March 1928, pp. 67-70; and "Preisausschreiben fiir eine Arbeit uber Raumschiffahrt," Der Flug, vol. 10, no. 7 (April 1928), p. 130.—Ed. 39. Woodford A. Heflin, "Astronautics," American Speech, vol. 36, October 1961, pp. 169-74, and "Robert Esnault- Pelterie," in Shirley Thomas, Men of Space (Philadelphia, New York, London: Chilton Book Company, 1968), pp. 20-24, (conversation between the author and Andre-Louis Hirsch). —Ed. 40. A. Hamon, "Assemblee generate annuelle de la Societe Astronomique de France" (5 June 1929); Gabrielle Camille Flammarion, "Les Progres de la Societe Astronomique de France," and "Prix et medailles decernes par la Societe," Bulletin de la Societe Astronomique de France, vol. 43, July 1929, pp. 301, 313, 314; and "Der REP-Hirsch-Preis Professor Herman Oberth zuerkannt," Die Rakete, vol. 3, 15 June 1929, p. 75.—Ed. 41. This epilogue appears on p. 576 of Ways to Spaceflight, by Hermann Oberth, NASA TT F-622, 1972, a translation into English of the book Wege zur Raumschiffahrt (Munich- Berlin: R. Oldenbourg, 1929).—Ed. 42. "The History of the REP-Hirsch Award," Astronautics, no. 34 (June 1936), pp. 6-7, 13; Ary J. Sternfeld, "Initiation a la cosmonautique," French manuscript translated and pub- lished in Russian as Vvedenie v kosmonavtiku [Introduction to Cosmonautics], Leningrad and Moscow: ONTI Glavnaya redaktsiya aviatsionnoi literatury, 1937. See also Joseph Krieger, Behind the Sputniks, A Survey of Soviet Space Science (Washington, D.C.: Public Affairs Press, 1958), p. 351. —Ed. 43. See pp. 3-97 of Interplanetary Flight and Communica- tion, vol. 3, (Theory of Space Flight), by Nikolai Alexeyevich Rynin, NASA TT F-647, 1971, a translation into English of the book Mezhplanetnye soobshcheniya Tom 3, vypusk 8, Teoriya kosmicheskogo poleta (Leningrad: Izdatel'stvo Aca- demii Nauk SSSR, 1932). It contains translations of REP's "Consideration sur les resultats de l'allegement indefini des moteurs," 1913 (see note 21); "L'Exploration par fusee de la tres haute atmosphere et la possibilite des voyages inter- planetaires," 1928 (see note 22); and "Astronautik und Relativitatstheorie, 1928." This last paper by REP first ap- peared in Die Rakete, vol. 2, 15 August 1928, pp. 114-17; 15 September 1928, pp. 130-34; and 15 October 1928, pp. 146-48, as translated from the French by Johannes Winkler. Sub- sequently the paper was expanded and included as pp. 228-41 in REP, L'Astronautique (note 20).—Ed. 44. "Prix et medailles descernes par la Societe," Bulletin de la Societe Astronomique de France, vol. 53, July 1939, p. 296. —Ed. 45. Op. cit., note 20. 46. 27 May 1931 record flight (16,000 meters) of Professor Auguste Picchard and M. Kipfer is discussed in "Le Mois, les records," L'Aerophile, vol. 39, 15 June 1931, pp. 179-180, and 15 August 1931, pp. 244-47. On 18 August 1932, Professor Piccard and M. Cosyns broke the previous record by reaching a height of 16,700 meters. "A Stratospherical Record, Balloon Ascent by Prof. Piccard, 10i/£ Miles Up," Flight, 26 August 1932, p. 798.—Ed. 47. Charles Dollfus, "L'Ascension stratospherique du pro- fessor Piccard et de Cosyns," L'Aeronautique, vol. 14, Septem- ber 1932, p. 268.—Ed. 48. Op. cit., note 2. 49. REP, L'Astronautique—Complement (Paris: Societe des Ingenieurs Civils de France, 1935). Lecture given to the Society on 25 May 1934.—Ed. 50. French patent 803,021, 29 June 1936, "de projectiles auto-propulseurs dont la charge propulsive est repartie en plusiers etages de combustion superposes suivant l'axe longi- tudinal de la fusee" [self-projectiles with propellant charge divided into several combustion stages superimposed along longitudinal axis of the rocket].—Ed. 51. "Election a l'Academie des Sciences," Bulletin de la Societe Astronomique de France, October 1936, p. 487. 52. American usage would define the term "jets" as in- jector orifices. 53. REP, "Reglage des orifices pour la premiere experience de refroidissement par oxygene liquide" [Adjustment of the orifices for the first experiment in cooling by liquid oxygen], Report no. 2125, Paris, September-October 1936; and "Essais de mise a feu avec refroidissement par oxygene liquide," [Firing tests for cooling by liquid oxygen], Report no. 2163, Paris, 15 October, 3 December, and 16 December 1936.—Ed. 54. REP, "Recapitulation des resultats obtenus au cours de l'anne 1937" [Review of the results obtained in 1937], Report no. 2333, Paris, 17 December 1937.—Ed. 55. A list of the French patents awarded him (to June 1929) appears in REP, Vie et travaux, pp. 93-100.—Ed. 56. REP, "Apparatus and Methods for Measurement of the Hertzian Hardness," Engineer, vol. 146, nos. 3788, 3789, and 3790, 17, 24, and 31 August 1928, pp. 180-81, 196-97, and 220-22. Paper read on 24 November 1927 before the British Section of Societe des Ingenieurs Civils de France.—Ed. 57. "Moteur balistique" pp. 7-8 in Note 30 above.—Ed. 58. "Utilization de l'energie des marees," REP, Vie et Traveaur, p. 38.—Ed. 59. REP, "Sur l'application de l'analyse dimensionnelle a l'etude de l'ecoulement turbulent," Comptes Rendus de l'Academie des Sciences, vol. 196, 26 June 1933, p. 1968; "Etude de l'ecoulement en regime turbulent a travers des orifices," Chaleur et Industrie, vol. 15, nos. 171, 172, and 173, July, August, and September, pp. 129-36, 189-98, and 235-42; and "Extension du principe de la loi-limite en analysis dimensionnelle," Comptes Rendus, vol. 203, 26 October 1936, p. 755.—Ed. 60. REP, L'Analyse dimensionnelle, Lausanne: F. Rouge, 1948. Additional publications of his concerning dimensional analysis include the following, all appearing in Comptes Rendus de l'Academie des Sciences: "Sur une confusion d'idees," vol. 225, 13 October 1947, pp. 606-09; "Sur une demonstration illusoire," vol. 225, 27 October 1947; "Variables de Vaschy et similitude mecanique," vol. 226, 14 June 1948, pp. 1935-38; "Action d'une variation du nombre des gran- deurs choisies comme principales sur les variables de Vaschy," vol. 227 30 August 1948, pp. 493-96; "Solution d'un para- 47. NUMBER 10 21 doxe," vol. 227, 15 November 1948, pp. 994-97; "Sur les systemes a quatrc grandeurs principales," vol. 229, 14 Novem- ber 1949, pp. 957-60; "Sur la distinction a faire entre systemes de grandeurs principales et systemes d'unites," vol. 229, pp. 1041-44; "II n'y a pas de systemes UES ni UEM, il y a des systemes d"unites dimensionnellement amorphes dont les unites sont reliees par des coefficients indimensionnes, syste- mes dont chacun peut-etre fait a volonte electrostatiquc ou clectromagnetique," vol. 229, 5 December 1949, pp. 337-41. Also, Dimensional Analysis, Translated by the Author and Entirely Recast From the French With Numerous Additions (Lausanne: F. Rouge, 1950).—Ed. 61. REP, De la bombe atomique a I'astronautique [From the atomic bomb to astronautics] (Paris: Ed. Aero-Club, 1947).—Ed. REFERENCES In addition to the sources mentioned in the footnotes, the following documents were helpful in preparation of this paper. 1. Alexandre Ananoff, L'Astronautique (Paris: Librairc Ai theme Fayard, 1950). 2. Andre-Louis Hirsch, "Robert Esnault-Pelterie, genial inventcur, pionnicr dc l'aviation, createur de I'astronautique [Robert Esnault-Pelterie, ingenious inventor, aviation pio- neer, creator of astronautics], unpublished lecture to the Automobile Club dc France, 28 March 1961. 3. J. J. Barre, Hislorique des etudes francaises sur les fusees a oxygene liquide [History of French Research in Liquid- Oxygen Rockets] (Paris: Imprimcrie Nationale, 1961). 4. J. J. Barre, Sur quelques particulates de la propulsion spatiale et de Vautopropulsion [On Several Features of Space Propulsion and Autopropulsion] (Paris: Imprimerie Na- tionale 1961). 5. J. J. Barre, Speech in Paris on the occasion of Esnault- Pelterie Day, 18 November 1961 (unpublished). 6. J. J. Barre, Speech in Paris on the occasion of the inauguration of Rue Esnault-Pelterie, 14 March 1966 (unpublished). 1. 1. Appendix Considerations Concerning the Results of the Indefinite Lightening of Engines This report was presented by Robert Esnault-Pelterie on 15 November 1912 to the Societe Francaise de Physique and published in an abbreviated version in the Journal de Physique (ser. 5, vol. 3, March 1913, pp. 218-30). The complete text, presented here, is the English translation distributed at the International Astro- nautics Congress at Amsterdam in 1958 as a memorial to REP and published in that year in Rocketry and Space Exploration, by Andrew G. Haley (New York: D. Van Nostrand Company, Inc., pp. 293-301). The ideas which will be developed here in this paper have been suggested to the author by the results that have already been achieved by light engines. He has been progressively led to ask himself what could possibly result from a further decrease in weight. For instance, if the weight per horse-power could be decreased almost entirely, what possibilities would be given to man? Would this progress only be limited to greater refinements in flying or would it open new horizons? And what would be these horizons? Innumerable authors have thought of man travelling from planet to planet as a subject for fiction. Everyone realizing without too much thought and effort the im- possibility of such a dream, it therefore seems that no one has ever thought to seek the physical requirements necessary for the realization of this dream and what would be the order of magnitude of the means one had to introduce. This is the only aim of the present study which is, it must be stressed, only a series of thoughts based on mathematical derivations. The first difficulty that strikes our mind is the fact that between planets there is no atmosphere, and therefore even an airplane could not find the slightest support for flight. Physiological difficulties will be examined later on. Let us just concentrate on our knowledge of Mechanics. If this knowledge will lead us to a realization of an engine, which would need no support for flight, it would be able to propel a body. As strange as it may seem to someone that hasn't thought about it, our knowledge gives us the answer. This engine has existed for quite a time: it is the Rocket. (The gun imag- ined by Jules Verne would crush the travellers as they departed and cannot qualify as an engine capable of propelling a vehicle.) It is often said that a rocket is propelled by a jet stream "through the air." The first part of this expression is correct, but not the second. A rocket would move just as well, if not better, in vacuum than in air. 23 24 SMITHSONIAN ANNALS OF FLIGHT Let us take a more striking example. Let us assume that a machine gun is fixed on a car capable of sliding without friction on tracks parallel to the gun. At every shot, the machine gun will move backwards according to a well established law in Mechanics. The respective momenta gained by the car plus machine gun and by the projectile are equal in magnitude and opposite in sign. Air resistance only enters into the phenomenon which decreases the resulting velocities. In the rocket, the machine gun projectile is replaced by the combustion gases which are emitted continuously. Let M0 be the total initial mass of the rocket, M its mass at time t and dm the element of mass of fluid which flows during the element of time dt considered. Let us first assume that the fluid emission is done with a constant velocity v with respect to the body and a constant decrease in mass per unit time ju. Let V be the body's velocity, F the propelling force and its acceleration at time t. The calculation shows that the phenomenon is described by the equations MdV = vdm = \xvdt (1) We will notice that if the whole body would be completely of consumable explosive (purely theoritically speaking, which has its importance) it would completely be used up after a time M0 T - — (2) The introduction of this time limit in the formula defining V as a function of t yields the equation (T - t)dV = vdt T-t thus V = v log (3) which gives for t = T V — — oo (assuming v > 0) This is no surprise for us, since the propulsion has remained constant as long as the mass was decreasing, due to the emission of the propelling gas until it vanished completely. The acceleration should therefore have increased and approached infinity. The equation relating the displacement xasa function of t is '-"Hi^y^h'} (4) and the corresponding distance travelled after complete consumption would be XT = —vT Aside from all external considerations, we have just seen that propulsion in vacuum is not an impossibility. However, it is not sufficient to move the body, it must be guided. NUMBER 10 25 In the present case, there are no difficulties in theory. To alter the vehicle's direc- tion, one need only incline the propulsor in such a way that the direction of the force it develops would be at an angle with the trajectory. If the displacement of the propulsor was not sufficient to obtain rotation in all directions, one or two smaller auxiliary propulsors would be enough to obtain complete maneuverability. II To remove a heavy body from the attraction of a planet, one has to spend energy. Let us consider a mass M at a distance x from the center of a planet whose radius is R. Let 7 be the acceleration of gravity at the surface of this planet. To move the body away a distance dx, it will be necessary to do an element of work dZ — My — dx x2 dZ = My which gives Z = MyR (-3 We can readily see that to move a given mass to infinity the necessary work to be done would be finite and given by Z = MyR Or if we let P be the weight of the body at the surface of the planet, then Z = PR We also see that if we consider the weight of the body as the result of the principle of universal attraction applied to body and planet, we can write after letting U denote the planet's mass MU R2 This gives for expressing the work necessary for removal of the body to infinity MU Z = k R Therefore, if we give initially to a body on the surface of a planet a sufficient velocity to remove from the planet, this body would increase its distance indefinitely. For the earth, the minimum velocity would be 11,280 m/s, i.e., a projectile launched from the earth with a velocity larger than 11,280 m/s (not considering air resistance) would never fall back. This critical velocity is exactly the same as that which a body would acquire falling toward the earth from infinity and having no initial velocity with respect to the planet. The motion of such a body would be given by the equation V2 = 2g — 26 SMITHSONIAN ANNALS OF FLIGHT We see that for X = R 1°) FB= -V2gR 2°) \mV2 = PR and this velocity limit VR for the earth is also 11,280 m/s. It was said before, that to remove to infinity a body from a planet, P being the weight at the surface and R the radius of the planet, the work to be done will be Z = PR For a body weighing 1 kg on the earth, this work would be Z = 6,371,103 kgm equivalent to 14,940 cal Let us recall that 1 kg of hydrogen-oxygen mixture with appropriate fractions contains 3860 cal for 1 kg; 1 kg of a powder containing gun-cotton and potassium chlorate is equivalent to 1420 cal per kg. We can see that the hydrogen-oxygen mixture contains slightly more than a fourth of what would be necessary to escape from the earth. But 1 kg of radium, liberating during its entire life»2.9 X 109 cal, would have 194,000 times more energy than needed. We will not talk here about the efficiency of a jet engine. If we consider a body which moves away from a planet according to any acceler- ated motion, we can see that at the time when its velocity will be larger than the one it would have at the same point moving in the opposite direction, falling from infinity without any initial velocity, it would be useless to give it more energy to make it go farther. Its kinetic energy would be sufficient for it to move indefinitely. The motion of a body subject to a constant force F larger than its weight, directed vertically upwards and away from the planet would be represented by the equation J 2SR2 v=\2Ax + 2R(A + g) x The body would acquire a sufficient velocity to permit the stoppage of propulsion at a distance from the center of the planet equal to -*H) F where A = — M We can see that if a body could move away from the earth with an upward propel- ling force exactly equal in magnitude to its weight, i.e., if A = g, it would reach that critical speed at a distance from the center of the earth equal to twice the earth's radius at an altitude equal to the earth's radius. This remark calls our attention to the fact that a body could perfectly well move away from a planet using a propelling force smaller than its weight. If the planet has an atmosphere, the body could in fact function first as an airplane, rising gradu- ally and increasing its velocity as this atmosphere became rarer and rarer, until it reached the critical velocity corresponding to the given altitude. NUMBER 10 27 III Let us consider what would be the required energies if we wanted, by this method, to transport a body from the earth to the moon and back. Let us consider that the operation will take place in three phases: 1°) The body is accelerated until it reaches the critical velocity of liberation 2°) The motor is stopped, and the body keeps moving due to its acquired velocity 3°) At the desired point, the body is turned upside-down and the motor that has been re-started diminishes the velocity until it becomes zero at the surface of the moon. First Phase We apply to the body a force F = ^P, therefore A = {fag which seems acceptable assuming that the vehicle would carry live beings. The critical distance is then v — 2JL.p x - TT** corresponding to an altitude of 5,780,000 m above the surface. The velocity at that instant would be V = 8180 m/sec The time necessary to reach that point would be approximately t — 24 min 9 sec Second Phase The body continues on its path due to its inertia; it is constantly attracted by the opposite gravitational forces of the earth and its satellite. Let P be the weight of the body at the earth's surface, Pt its weight at the moon's surface and p the radius of the moon, D = x + y the distance between the two planets; the calculation gives v= 12 (g— + 0.165-*- + 0.82 X 106j At the point where the respective gravitational forces of the earth and moon cancel each other, the velocity would be v = 2030 m/sec It is the lowest velocity. At the moon's surface it would become approximately v = 3060 m/sec 28 SMITHSONIAN ANNALS OF FLIGHT The velocity of the body falling freely from infinity to the moon would be Oao = 2370 m/sec The time used to go through the second phase can be calculated approximately by neglecting the moon's action which is entirely negligible during the total journey. It would be the same time as that taken by the body during a free fall from the moon to the point where we had stopped the engine: t = 48 hr 30 min Third Phase One must now decrease the speed by turning the body upside-down as said before, and by re-starting the motor. What will be the law of this slowing down? We would establish it in the same manner as we did for the earth; but the moon's attraction being much smaller, and as we do not at this stage seek a great precision, we will deduct from the acceleration due to the propulsor, half the acceleration due to the moon, and we will assume the motion uniformly slowed down under the action of this fictitious acceleration. We find that the body has to be turned upside-down at a distance from the moon's surface equal to d = 250,000 m approximately This point is so close to the moon, and the present calculations not being rigorous, the time necessary to reach the surface could be mistaken for the time necessary to reach the moon itself. The time of the slowing down will be t — 226 sec = 3 min 46 sec The total time for the whole process is approximately then: First phase 0 hr 24 min 9 sec Second phase 48 hr 30 min Third phase 0 hr 3 min 46 sec 48 hr 58 min approximately The return trip could be done by reversing the process and in the same time. It must be pointed out that, by this means, the propulsor is used only 28 min going and the same time coming back unless the earth's atmosphere is used for the slowing down process, in which case the 28 min used for the departure, and the time necessary to orient the body properly, would suffice. We will now consider the power actually needed to realize these minimum condi- tions and the resulting efficiency output of the motor with respect to the theoretical work given. If we consider a 1000 kg vehicle out of which 300 kg are consumable; and if the engine has to work 27 min +3.5 min and to have a sufficient flow margin 35 min NUMBER 10 29 = 2100 sec, the rate will have to be 300 = 0.143 kg/sec 2100 and the fluid's expulsion velocity v = 65,300 m/sec Therefore, by providing per kilogram of fuel T = 217.2 X 106 kgm or 512 X 103 cal one sees that the mixture H2 + O would contain 133 times too little energy and the most powerful explosives 360 times too little. On the other hand, 1 kg of radium would contain 5.670 times too much] The power of the motor necessary for our 1000 kg vehicle would be 300 X 217.2 X 106 = 414,000 HP 2100 X 75 We could also see that the efficiency of the jet engine is in our particular case quite bad. Since to remove a mass of 1 kg from the earth to °o, we have to apply to it 6,371,103 kgm and we have spent 217.2 X 106, so that the efficiency is p = 0.0293 Moreover, to give a gas an ejection speed of 65,300 m/sec in vacuum, we would have to reach the fantastic temperature of 2.525 X 106 degrees. In air, it would be even worse, since added to this temperature one would need a pressure of about the same magnitude. IV As an indication, we could assume the body moving to infinity, and also that we have kept the motor working even after the critical speed is reached, so that it eventu- ally acquires and conserves a speed near to 10 km/sec. The times necessary to reach the closest planets as they attain their conjunction with the Earth are respectively: For Venus 47 days 20 hr For Mars 90 days 15 hr These figures are merely mentioned for curiosity and we must also notice that the amount of work to cover this distance would not be much larger than the minimum necessary to remove the body from the earth. In fact, once the vehicle has reached a sufficient distance, it would keep on going due to its inertia without being slowed down by the earth's attraction which has become quite weak. In other words, the difficulty would be to overcome the earth's attraction; but if some day this difficulty would be overcome, it would hardly be more difficult to reach a very distant planet than a close one. Subject, of course, to a cramped and hermetically closed vehicle being inhabitable for a sufficient amount of time and to another difficulty that we will consider later on. 30 SMITHSONIAN ANNALS OF FLIGHT In all the preceding sections we have only considered the theoretical possibility for a body with special properties to travel between the earth and the moon. This is a problem of pure mechanics which does not really answer the question of whether man will be or will never be able to leave his world to explore others. The complete study of the question will lead to the study of the physiological con- ditions that must be fulfilled so that life will be possible under such conditions. The progress made in submarines can already make us consider as quite feasible in the future the regeneration of an atmosphere which has been confined for some hundred hours. The question of temperature deserves being particularly considered. It is often said that the interplanetary spaces have an almost absolute zero temperature. The author believes it is false. The concept of temperature is only related to material bodies and therefore a vacuum cannot have any. If the amount of heat absorbed per unit time by our vehicle is less than the quantity of heat that it radiates, its temperature will decrease. If the amount of heat received and absorbed is greater than the amount that is radiated, the temperature will increase. It would therefore be possible to construct a vehicle in such a way that one half of its surface would be of a polished metal and the inside insulated. The other half of the surface, for example, would be covered of copper oxide to give a black surface. If the polished face would face the sun, the temperature would decrease. In the opposite position, the temperature would increase. All the difficulties that we have just considered do not seem to be theoretically impossible. But a new difficulty will arise which although a mechanical solution offers itself, will nevertheless complicate further the problem. In fact, in the calculations related to the vehicle's journey from the earth to the moon, we have considered that we were applying an acceleration A — io£ and this up to a distance of 5780 km from the earth's surface. During all this phase of the voyage, the travellers would therefore have the impression of weighing ^}/{Q of their weight. One may hope that as unpleasant as this sensation may be it will not cause any disturbance to a human organism. But what is most alarming is what will happen at the instant of sudden stoppage of propulsion. At this moment, the traveller would suddenly cease to have any weight and he would have the sensation that both he and his vehicle were falling in a void. If the human organism cannot go through such vicissitudes, we would have to replace the absence of a gravitational field by creating constant artificial acceleration produced by the motor. If this acceleration is made equal to gravity, the traveller will constantly feel he is weighing his normal weight, without any consideration of the fact that he may or may not be in the gravitational field of a planet. It is obvious that this kind of a process would introduce a very important difficulty with regard to the amount of energy which would become necessary, and would NUMBER 10 31 bring us far away from the conditions of realization which were studied previously and which were already quite extreme. If we use the formula representing the law of motion of a body acted on by a constant force due to the earth and if we assume that until we have reached the maxi- mum velocity between earth and moon, the acceleration used is equal to 1K0 g> then the other maneuvres will be done with an acceleration equal to gravity. The moon's influence can be neglected, it being so small. It is found that the vehicle has to be reversed at a distance from the center of the earth equal to 29.5 times the earth's radius. The speed at this instant of time would be 61,700 m/sec, then the reversed vehicle would be slowed down by a force equal to its weight on the earth. The time used to reach the moon would be t = 3 hr 5 min But in this new case, the work to be furnished, using the assumption of a 1000 kg vehicle of which 300 kg are consumable, would reach 67.2 X 106 cal/kg of fuel, i.e., 131 times more than in the first case. Dynamite would be 47,300 times too weak, but radium would still be 433 times too powerful. As to the necessary power, it would be 857 X 1010 = 4.76 X 106 HP 24,000 X 75 If we now assume that this method of constant propulsion is used for voyages to the closest planets and investigate what the times and velocities would be, we find for the maximum velocity: For Venus 643 km/sec For Mars 883 km/sec and the corresponding times: For Venus 35 hr 4 min For Mars 49 hr 20 min VI The maximum velocities we have just considered are evidently fantastic. However, there exists at least one celestial body which reaches such velocities: Halley's comet. Only the forces and energies which seem to be contained by molecules could produce concentrations of power and work similar to those we just considered. If we suppose for a moment that we have available 400 kg of radium in our 1000 kg vehicle and that we knew how to extract from it the energy within a suitable time, we should see that these 400 kg of radium would be more than enough to reach Venus and come back (with a constant acceleration), so that such a formidable reservoir would be just enough for man to visit his closest planets. Early Italian Rocket and Propellant Research LUIGI CROCCO, Italy Introduction The person invited to present to this symposium a review of our early work in the field of rockets, was my father, General G. Arturo Crocco, a well known personality in the aeronautical world be- cause of his extraordinary contributions to the de- velopment of aviation, starting in 1904, and also a pioneer in the field of rocketry. In view of his very advanced age1 he could not undertake the task, which was then delegated to the son, his closest col- laborator during those pioneering efforts. Considered retrospectively and objectively, this research on solid and liquid propellant rockets (and associated fields) produced rather interesting re- sults, especially considering that when it started in 1927 very little scientific effort had been devoted anywhere in the world to the problem, which had been tackled mostly empirically by more imagina- tive than scientifically grounded inventors (there were, of course, notable exceptions). Nevertheless, and unfortunately, none of this work was allowed to appear in the press at the time for security rea- sons. Even more strangely no internal classified reports were ever submitted to the sponsors. The relations with them were limited to verbal exposi- tions of the results. Actually, the very idea of spon- sored research at that time was completely extrane- ous to the military organizations, and there were no rules whatsoever to regulate our exceptional re- lations with the sponsoring agencies. Hence the records of this research are entirely of a private nature, such as the record books of my father, or my own notes, and in particular an internal report I wrote in 1935, summarizing the research up to that moment. From that report I extracted a few items for a very short exposition which I published in 1950.2 It may be, then, that this opportunity will help to fill an inexcusable gap in the literature on pioneering work in rocketry. It all started as follows. My father has always been one of those scientists for whom the practical application of his scientific results counts as much as the scientific effort itself. He intensively applied this double capacity for research and invention in the field of aeronautics for many years, including those of the first world war, as an officer of the Genio Militare Italiano. At the end of World War I, convinced, as were many others, that the time for wars was over, and after resigning from the armed forces, he started an intense civilian activity in con- nection with industry, which meant, at the time, in non-aeronautical fields. However, his heart always kept him thinking and working, as a hobby, on advanced aeronautical and propulsion concepts, and indeed a number of his publications of the post World War I period show his intense interest in rocketry and supersonic flight.3 In 1927 he gave a private lecture to the members of the General Staff, headed then by General Badoglio, on the military possibilities of rockets, theoretically with unlimited terminal velocities, as compared to the fundamentally limited muzzle velocities of artillery. Badoglio, quite impressed, gave him from his secret funds 100,000 lire (5,000 dollars) for research and development in the field of solid propellant rockets. Having, as a civilian, no laboratory wherein to conduct the research, my father made an agreement with one of the foremost Italian explosive manu- facturers, Bombrini-Parodi-Delfino (BPD), whereby the experiments would be carried out in their SEGNI facilities, free of charge, with the collabora- tion of their Technical Director, Dr. Marenco. My father had to supply the apparatus and also the 33 34 SMITHSONIAN ANNALS OF FLIGHT propellant, unless available at BPD. Shortly there- after, my father was called to a Chair of Aero- nautics at the newly constituted School of Aero- nautical Engineering of the University of Rome. What Propellant and How Utilized? The choice of the propellant represented a very important initial step. Of course, an impressive amount of very scientific data was already known to the artillery people; it was, however, limited to ranges of pressure suitable for guns but not for rockets. Very little, if anything, was known, in- deed, about the behavior of conventional gun propellants at pressures below 100 atmospheres. It might have been for this reason, or out of a lack of sufficient background, that so many rocket pioneers derived their concepts from the very empirical formulas of pyrotechnicians rather than from the science of artillery. A notable exception to the rule was provided by an Italian pioneer who proposed the use of dynamite for rockets. Maybe he was the precursor of project Orion! I would like to add here that, in reality, the intuition of the rocket pioneers may not have been so bad because it is clear today that the greatest present and future achievements of solid propellant boosters follow a line which, conceptually, is more directly derived from pyrotechnics than from gunnery. As a sci- entist, however, my father was definitely more at- tracted by the clear background of artillery powders than by the obscure concoctions of fireworks, and his natural choice went immediately to the double- base powders. The next step was to decide how to utilize these powders so as to obtain the relatively long deflagra- tion times required by rockets, as compared to the extremely short times characteristic of guns. It was immediately clear that the key was to use the largest possible "grain" size, particularly of the "constant burning-area" type. However, the great advantages that might derive from the possibility of "restricted- burning" grains did not escape my father's search- ing mind, and he decided to work in both direc- tions. FIGURE 1.—First solid propellant test chamber. NUMBER 10 35 First Tests on Solid Propellants The first experimental series was conducted in 1927 and 1928 at BPD by my father, with the col- laboration of Dr. Marenco. Then 18 and an engi- neering student in my first years at the university, I was the second collaborator, free of charge. The first chamber designed to test the above concepts is shown in Figures 1 and 2. The propellant in C was ignited by an ignition charge set off via a percussion cap by a mechanical device p-m. The combustion products were exhausted at the opposite end through a nozzle F. The chamber was intended to contain at most 0.1 kg of propellant. With a total volume of 600 cc the maximum combustion pres- sure was 2000 atm and the thick walls were calcu- lated for 4000 atm at the elastic limit. As an addi- tional safety measure the nozzle end was designed to burst open at 1000 atm. All these safety precau- tions were, of course, necessary because the tests involved a great amount of uncertainty and were to be conducted on an open test-stand, under our very eyes. Indeed, more than once during the pre- liminary testing the protective action of the safety features of the nozzle end were called upon. The chamber was free to move axially on rollers and the thrust was converted into oil pressure by a piston P3. Both chamber pressure and thrust were recorded on a rotating drum by means of a double channel mechanical manograph of the kind used in gas engines. However, the preliminary tests were carried out without the manograph. The only instrument was a "crusher" (Cr, Figure 2) intended to provide the maximum pressure. Numerous attempts were made to find a reliable binder between the double-base cylindrical charge and the brass case containing the charge, so as to inhibit burning on all but the frontal surface. These attempts failed to attain the necessary reliability, and once in a while resulted in strong overpressures, reaching once the burst limit of the nozzle end, because of the failure of the binder. As a result, my father decided that the inhibition of the burning surface was too unreliable and he decided to concentrate on charges with un- restricted burning. The propellant chosen for these initial tests was cordite, readily available in appropriate sizes at the Naval Arsenal. The corresponding composition of it is shown below: 25 62 5 8 Too Nitroglycerin Nitrocellulose Vaseline Barium Nitrate Total Tubular charges of approximately 21 mm outside diameter and 7 mm inside diameter were used. The charges C were free to move in the brass case B (Figure 3) but held within it by a charge-holder g. The ignition charge c was a mixture of 2 g of bal- listite and 1 g of black powder. In order to help the propagation of ignition, because the ignition charge was located downstream of the main propellant, three thin strips of ballistite were inserted into the propellant hole. After the initial test, further to improve the regularity of ignition, which still was not entirely satisfactory, the nozzle was provided with a burst diaphragm. The diaphragm, visible in the details of Figure 2, kept the chamber closed until a preassigned burst pressure was reached. The FIGURE 2.—Schematic sketch of first solid propellant test chamber. 36 SMITHSONIAN ANNALS OF FLIGHT C \ff FIGURE 3.—Propellant charge container. ^ -- --—- — --- nozzles used in these tests had throat diameters of either 7 or 8 mm. Samples of three types of pressure records ob- served are shown in Figure 4: some were quite "normal" (4a); others were rather irregular (4&); and some definitely "abnormal" (4c). The cause of the abnormalities was attributed to poor effective- ness of the charge holder, and indeed a better design of this essential detail resulted in complete suppression of such anomalous tests. However, from the numerous tests it was clearly evident that the equilibrium pressure was not very well defined and could vary substantially from test to test, much more than the small amount shown by Figure 4a, as a result of irregularities in the burst pressure, the nozzle and throat area, and the grain dimensions. P (atm) zoo 100 0 Irregularities in the apparent duration of burning even at equal pressures, such as shown in Figure 4a, were caused by irregularities of the drum revolving speed. This defect was inherent in the instrument and actually prevented accurate determination from individual tests of the burning rate and of the specific impulse. The value of this last quantity oscillated between 150 and 170 seconds. Based on these results the small rocket stabilized by tail fins (Figure 5) was designed and launched. The corresponding charge was tested in a chamber, as shown in Figure 5, where only the pressure could be recorded. Larger test rockets, also with aerodynamic stabilization, are shown in Figure 6. The corresponding charge was divided into three tubular grains of 300 g total weight and was tested a « T(.01 sec) FIGURE 4.—Pressure records (in atm vs. time in sec): a, Normal tests; b, irregular tests; c, abnormal tests. NUMBER 10 37 FIGURE 5.—Small fin-stabilized rocket, which used a single tubular grain, and test chamber for it (bottom). in the chamber shown in Figure 7, where again only the pressure was measured. Figure 8 shows, super- imposed, three pressure records from this apparatus, all corresponding to the same burst pressure of 100 atm (nominal). The poor reproducibility of the pressure level is evident, and as a result the rocket wall had to be designed rather thick. However, it was still sufficiently thin to become overheated. In the first rockets launched, the wall reached red heat at the end of the combustion time. To avoid over- heating a thin insulating layer of asbestos was in- serted between the chamber wall and the propel- lant. These rockets were launched with good results and reached velocities of about 1000 fps, which were in agreement with the estimated velocity. The main inconvenience observed in the launching of both types of rockets was the lack of accuracy of their trajectory. It was attributed to the erratic transverse displacement of the center of mass re- sulting from the fact that there was nothing to prevent the lateral motion of the three tubular charges when their diameter decreased. To restrict this motion, stabilization by spinning the rocket about its axis was attempted by impressing a fast rotational speed to the rocket holder prior to igni- tion. This launcher is shown in Figure 9. The whole rocket holder was set in rotation by an electric motor. Moreover, the three tilted exhaust nozzles provided a tangential thrust component after launching. The ignition burst diaphragms were replaced by shear pins (r) which firmly held the exhaust nozzle terminal sections pressed against a terminal plate until a preassigned pressure was reached. In another version of the spinning rocket the initial rotation was obtained through a fast burning charge located in an annual chamber around the single exhaust nozzle. This charge was ignited just prior to the main charge and exhausted through small tangential nozzles. The spinning rockets did not provide any more precise trajec- tories than the fin stabilized rockets. Further Research on Solid Propellants Late in 1928 my father was called from the re- serve back to active duty as a general and asked to become Direttore Generale delle Costruzione Aeronautice in the Ministry of Aeronautics, while still continuing his teaching activity as a professor of the School of Aeronautical Engineering. This event had two important effects on our rocket re- search program. First, the facilities of the Ministry Of Aeronautics became available for the continua- tion of our research; and, second, my father became immediately deeply involved in pressing problems of broader and more immediate interest. The first was a very welcome improvement of the situation, especially in view of the fact that the 100,000 lire of the General Staff were almost exhausted. The second was, on the contrary, a blow to the future dynamic development of the applications, if not to the fundamental aspects of the research. Indeed I was now, practically alone, in charge of our re- search effort. My father only devoted a little time to it in the evenings, when we discussed our prob- lems at home. Because my mind has always been more attracted by questions solved by basic re- search, these naturally gained prevalence with respect to questions regarding applied research. I should add that, of course, my studies prevented me from devoting my full attention to the research project. The experiments took place in Rome in an 38 SMITHSONIAN ANNALS OF FLIGHT FIGURE 6.—Large fin-stabilized rockets, which used three tubular propellant grains. FICURE 7.—Test chamber for larger rockets. isolated suite of two rooms which was assigned to these tests at the Stabilimento di Costruzione Aeronautiche (SCA), then on Viale Giulio Cesare. There, assisted by Signor Laghi, an excellent tech- nician of the old school, I first carried out a series of tests in the chamber shown in Figure 1, used as a constant volume chamber by closing the nozzle. iil^i^Y, XI =0=t=^=ft irlr\ I compared the performance of tubular charges of the cordite used to that time, with a new double- base powder used by the Navy, the so-called C- powder, the composition of which is as follows: 23.5 70.5 5.0 1.0 HJOlT Nitroglycerin Nitrocellulose Vaseline Sodium Bicarbonate Total The first advantage I expected from the change in propellant was related to the higher regularity of the grain dimensions, a consequence of the different manufacturing process. The manufacture of cordite requires the evaporation of a solvent which must be added to reach the necessary plasticity. During the drying process the grain shrinks, with resulting roughness of the surface and irregularity of the dimensions. In the case of the C-powder the neces- sary plasticity is attained by performing the opera- tions at 100°C without solvent; the surface of the finished product remains quite smooth and the dimensions quite regular. The second advantage I NUMBER 10 39 P (atm) / (In,., - Hvv/" 3 WM ' = = a -- ^ J ' tf /.J /^ ?^ JP « T (.01 sec) FIGURE 8.—Pressure records (in atm vs. time in sec) of larger rockets, using cordite as propellant. FIGURE 9.—Launcher for spin-stabilized rockets hoped from the change was due to the different composition, which led me to expect a smaller sensi- tivity of burning rate to pressure. I had reached the conclusion that the erratic behavior of the equi- librium pressure was due both to the geometric ir- regularity of the cordite and to its high pressure sensitivity. This conclusion, subsequently confirmed by the experiments, was based on simple calcula- tions showing that deviations within ±5 percent of the dimensions of the tubular charges (that is of the order ±0.5 mm, on the radius, a very realistic deviation for cordite) would result in a range of equilibrium pressures from 30 to 186 atm for a nominal pressure of 100 atm if the burning rate varied with the 0.875 power of the pressure, but only in the range from 82 to 119 atm for an ex- ponent of 0.625. The results of the constant-volume tests are sum- marized in Figures 10 and 12. Figure 10 gives the pressure history obtained with different amounts of the two propellants. It was immediately evident from the smaller curvature of the C-powder (Polvere C) records that the pressure sensitivity is decreased. Figure 12, however, shows that where the terminal pressures are plotted against the charge weight, the "effectiveness" of the two powders is very nearly the same. For both powders the pressure sensitivity de- crease with decreasing pressure since the pressure/ density ratio appears to follow very closely a p0-25 power law within the pressure range of these tests. Tests conducted next in the chamber shown in Figure 1, with the C-powder and an exhaust orifice of 7 mm, confirmed with their high regularity the superiority of this type of propellant as compared to cordite. For example, Figure 11a shows two repre- sentative pressure curves. Figure 116 shows a record obtained in the small test chamber shown in Figure 5. This chamber, of all those employed, allowed the highest charge density of 0.71 kg/dm3. In compari- son, the chamber in Figure 1 allowed a loading den- sity of 0.17 kg/dm3 and the chamber shown in Fig- ure 14, a charge density of 0.54 kg/dm3 The excellent behavior of these tests encouraged construction of the new test chamber (Figure 13) for 300 g of nominal charge. For safety reasons an expansion chamber 5 was attached to the test chamber to provide additional volume for the gases in case the pressure would rise beyond 500 atm and break the diaphragm R. But this precaution was proved superfluous by the great regularity of the tests. The chamber B was mounted as a pendulum, as indicated in Figure 14, to allow measurement of the thrust. The values of the burning rates obtained from the tests on the two propellants are summarized in 40 SMITHSONIAN ANNALS OF FLIGHT 0 10 20 30 centesimi di wcondo t FIGURE 10.—Comparative pressure records in closed chamber for cordite and C-powder. us sir E IS ft ZS 30 3S *0 IS T (.01 sec) FIGURE 11.—Pressure records (in atm vs. time in sec): a, C-powder combustion within test chamber shown in Figure 1; b, C-powder combustion within test chamber shown in Figure 5. NUMBER 10 41 a - —i —i ! i r 1—' i p I. J 1 Q-0,4p0-75 QK r . -, - 11: ■ : ! ; r 40 - — —- -\ i V/^- i y^\ • Cordite austHaca . o Polvere C - - — - n •z -4 • 1 , • i 30 —< ' i : ,_. , i 1. 1 . 1 • i j -- i ! ' ' • 20 i i j . i I ; i x i_..:, i i 10 i i I i i i ! i i i i 11 _ i ; i 1 ; i I ■ 1 ! ! ! ! ' i ! i i ! : n* I 1 1 i ; i 1 i i 1 ! 1 1 1 J 1 100 200 FIGURE 12.—Terminal pressure in 300 400 500 p atm. closed chamber vs. charge weight for cordite and C-powder. -J-H-i FIGURE 13.—Test chamber for three tubular grains. 42 SMITHSONIAN ANNALS OF FLIGHT Figure 15. The dispersion of the measured values is again due substantially to the poor behavior of the recording drum. The burning rate of the cordite follows more or less a po.75-HO.7s iaw j"or the C- powder an exponent of 0.53 best fits the results. Several theoretical works were also carried out. Figure 16 shows, for instance, the results of a theory developed for the calculation of the pressure distri- bution within the hole of a tubular charge for a burning rate given by apn. The coefficient £ is given FIGURE 14.—Front view of the pendulum test stand with chamber. where 8 is the propellant density, r the hole radius assumed constant, and T the gas temperature at the burning surface. R and y have the conventional meanings. The distance from the middle section of the hole is indicated by s. The terminal points on each curve correspond to choked conditions at the two ends of the hole (this way my first contact with the fundamental importance of Mach 1 even in the presence of combustion phenomena). Choking ap- c -- - -- .... — 1 "" .s T 2 B • JRDITE C * 0 * 6 ♦ — — — .... .._. (A E o / 1.5 i / '/ y / / / / — ... 1 ♦ / / / v' • ♦ * o /* • • _ .1 • ' _.. — >. — 0 100 1.5 0.5 200 1 1 1 1 1 • LA P0LVERE C - - — — t i A i ^ K • / * ' # • ... / < rf> o _. - _ /b O / * / - — __ — — ■— - — 150 200 FIGURE 15.—Burning rates for cordite (top) and for C-powder. pears for a certain charge length, beyond which no steady solution to the problem exists and the pres- sure must steadily rise in the hole. It seemed to me at first that this was an important finding, and I was disappointed when I calculated that for the actual charges the maximum value of the abscissa NUMBER 10 43 1 200 P 1 n-1 Jt>\ *A E a 0 150 ^s0 / \ / \ / \ / 00 'C 0 - / \ / i \ 57 V SO 50 -^ s ( , 0 2 3 |p.| 4 3 2 10 1 200 P - n = 0.5 " E A <\ * \°o 150 fr / i\ 100 1 / s'* 7 \ / \ 1 i 4 50 ^s \ v \ 0 60 SO 40 30 FIGURE 16.—Theoretical internal pressure distribution for tubular charges with burning rate proportional to p (top), and proportional to pi was around 1 for n=1.00 and 3 for n = 0.5 (see Figure 16), indicating that the actual conditions were very much below choking. By the end of 1929 the Italian General Staff, judg- ing that the dispersion obtained in our tests was too great if compared with the dispersion of guns, and that the velocity was too low, lost its interest in the powder rockets and the research was sus- pended. However a new phase of our research was started, more suitable for possible future applica- tions to aeronautical problems and supersonic flight. Research on Biopropellant Rockets This part of our research was also partially sup- ported by the General Staff through a second allo- cation of secret funds. My father discussed with Professor Francesco Giordani, an eminent chemist and personality of the Italian scientific world, the choice of the liquid propellants. The preference being, for practical reasons, given to storables, the choice fell on benzene as fuel and nitrogen tetroxide as oxidizer, because of the easy availability and low cost of both. Concentrated nitric acid was also con- sidered, but the problem of the tanks appeared more difficult than for nitrogen tetroxide. It must be realized that stainless steel was only beginning to appear on the horizon, in very limited forms, and its technology was in its infancy. My father decided that a chemist was needed to help me in the manipulation of the hazardous chemicals, and he hired a Dr. Corrado Landi, with whom, indeed, I collaborated for nearly two years. He was in charge of the propellant supply, while I was myself working on the design of the combustion chamber. My father, of course, gave as much super- vision and advice as his very busy time would allow. FIGURE 17.—Liquid bipropellant test rocket engine. A very conventional type of propellant feeding 44 SMITHSONIAN ANNALS OF FLIGHT system with pressurized propellants was adopted, but special bottles for the nitrogen tetroxide had to be manufactured out of pure aluminum, in view of the corrosiveness which could result from residual traces of water. The chamber is shown schematically in Figure 17. It incorporated several features of present day rockets, such as the regenerative cooling and the impinging jet injector. Credit for the prac- tical design of this chamber as well as of the other equipment described in the rest of this paper goes to Ing. G. Garofoli. The nozzle, including the con- vergent part of the chamber, was cooled by fuel cooling passages /; the rest of the chamber by the oxidizer cooling passages S. The propellant flow was hand-controlled by means of valves Rp and R0 located at the entrance of the cooling passages. From the cooling ducts the propellants were brought to the injector /, consisting of three con- centric annular injector slots, the central one, p, for the fuel; the other two, O, for the oxidizer, re- sulting in three impinging jets. Shown on the figure is the rather unconventional use of a re- fractory liner Z to decrease the heat transfer to the chamber wall. The refractory material was zirconia, chosen for its high melting temperature. The whole chamber was built of stainless steel. For the nozzle I had selected a steel developed in the United States, because it could be welded. Tungsten-arc welding was used, but the welding was porous and gave lots of trouble. The complex- ity of the chamber design was necessary to make the chamber leakproof without welding. It was manufactured out of a block of stainless steel from COGNE Steelmills; so was the injector unit. Cham- ber pressure and propellant injection pressures were measured by gauges, as shown in Figure 17, and the whole chamber was mounted on rollers to allow the direct measurement of the thrust, which was designed to be around 1250 g, at 10 atm chamber pressure. The ignition sequence was rather in- volved. A small gas torch v was first inserted into the appropriate passage in the chamber walls. Gaseous hydrogen and gaseous oxygen, provided by an auxiliary feed system, were then admitted through the propellant valves under very moderate pressures, resulting in nearly atmospheric combus- tion. The torch was then retracted, the torch pas- sage shut off, and the pressure of the gases grad- ually increased until a noticeable chamber pressure resulted. The transition to liquid propellants could then be effected without difficulty. This chamber was successfully tested late in 1930 by Dr. Landi and myself in a room on the courtyard of the Institute of Chemistry of the Uni- versity of Rome, then located at via Panisperna. It had been graciously assigned to our research, upon my father's request, by his director, Professor Nicola Parravano. I suppose that this decision of my father of not carrying the tests within the laboratories of the Air Ministry was dictated by the sponsoring General Staff. During the ten-minute run our excit- ment grew very high, reaching its climax with the successful conclusion of the test. In our enthusiasm we did not realize what an extraordinary noise level we had introduced without warning in that peaceful courtyard, all devoted to basic (and silent) chemical research. What an anti-climax it was when the noise subsided and we heard a loud voice asking what in the h— was going on there. Dashing to the windows we saw the angry and puzzled faces of Professors Parravano, Malquori, and De Carli at their respective windows. With an evident breach of security we had to provide the technical back- ground for the deafening noise, after which Profes- sor Parravano had a meeting with my father. They agreed that the project had to be transferred to a more suitable location. A few weeks later, while in his laboratory, Dr. Landi was suddenly struck and died without regaining consciousness. I always wondered whether his premature death (he was only 25) could have had something to do with his han- dling of nitrogen tetroxide and too frequent acci- dental inhaling of its toxic vapors. In which case, Dr. Landi's name should deservedly be added to the human life toll of rocket development. With the death of one of the principal collab- orators, and the fact that I had to concentrate on the preparation of my theoretical thesis for my forthcoming degree in engineering (which I ac- quired in July 1931); the research was temporarily stopped. The available funds were exhausted, and despite the promising results obtained, the General Staff did not renew its contract. Research on Monopropellants Research was not resumed until the second half of 1932, after I had graduated and satisfied my mili- tary obligations. But in the meantime, as a result of long and fruitful discussions between my father NUMBER 10 45 and myself, the aim of the research had switched toward the study of monopropellants. Also, the re- search was now financially supported by a new sponsor, the Italian Air Force. It had new head- quarters, the laboratories of the Istituto di Aero- nautica Generale of the School of Aeronautical Engineering of the University of Rome. We also welcomed to our program a new, very competent, collaborator, the Doctor of Chemistry Riccardo M. Corelli, later Professor of Aeronautical Technology at the same school. I remember quite distinctly how the first idea of the monopropellant was born during an evening stroll under the trees of Via Nomentana. My father was wondering about the possibilities of controlling solid propellant burning by introducing it in the combustion chamber as a slurry of fine solid-propel- lant particles in suspension (but not solution) in a liquid. The discussion centered on the way combus- tion of such a mixture could take place. I remember how, in what was a sudden illumination for my still unexperienced mind, I realized the meaning of thermochemical calculations which, independ- ently of the burning mechanism, allow a simple prediction of the composition and state of the gases resulting from the combustion of any mixture of chemicals as soon as the temperature is sufficiently high. In practice, abandoning the not very practical idea of a solid propellant slurry, we chose to work with a liquid explosive, desensitized by dilution with an inert solvent. The most easily available and one of the most effective liquid explosives being trinitroglycerine, we decided to try it despite its bad reputation. However, we also considered other substances, such as dinitroglycerin or dinitroglycol. We performed a limited number of tests with these substances. It was known that a relatively small frac- tion (30 percent) of an organic solvent such as methanol could practically make trinitroglycerin insensitive to shock. Dr. Corelli carefully checked this and other statements in the literature on the subject, with a small amount of the explosive pre- pared in our laboratory. After this I felt sufficiently confident to carry personally on a night train from Turin to Rome a few liters of the mixture which had been prepared for us at the powder plants of Avigliana. This was, of course, a flagrant violation to the official regulations concerning the transpor- tation of explosive materials, and I shudder today at the responsibility I was taking. However, it was the only way to avoid the endless red-tape involved in legal shipment. Gasification tests were conducted in the appa- ratus shown in Figure 18. The monopropellant m contained in the tank b was pressurized, through the separating piston p by the gas of bottle a. The FIGURE 18.—Monopropellant gasification apparatus. 46 SMITHSONIAN ANNALS OF FLIGHT FIGURE 19.—Nitromethane engine. combustion chamber C; all lined with insulating re- fractory material, contained at its bottom a crucible filled with pellets of refractory material. The cru- cible was electrically brought to a deep red tem- perature, after which the current was turned off and the monopropellant injection through the in- jector was started. The resulting gases were evacu- ated through a small nozzle and collected in a gasometer G, after cooling and separation of the condensed fraction. FIGURE 20.—Demonstration turbine for operation with nitromethane. The nitroglycerin mixture responded exactly ac- cording to the predictions of the thermochemical calculations, proving my point (if, indeed, it needed proof!). More important, it provided a hint of the practical possibilities of liquid monopropellants. However, this particular monopropellant was con- sidered to be unsafe because of the possibility of separation, either by evaporation or by water addi- tion, of the two components. Indeed, we had our- selves experienced a delayed explosion in the feed- ing line of Figure 18 which could be attributed to this reason. Hence Dr. Corelli prepared a list of possible organic solvents, presumably better than methanol with respect to separation, and I started the thermochemical calculations using each of them as a diluent. This was the path that made me acci- dentally stumble on the exceptional properties of mononitromethane. I was indeed surprised to find that while, ac- cording to my calculations, other solvents provided results comparable to those of methanol, the out- come for nitromethane was well in excess of the others from the point of view of the overall heat of reaction and combustion temperature. Then, performing the calculations for nitromethane alone, I found this compound to be in itself an excellent monopropellant, better than any of the safe nitro- glycerin mixtures. Of course, this was a surprise, since the explosive character of nitromethane had never, to our knowledge, been pointed out. It is natural that after this find our research con- centrated on nitromethane. Dr. Corelli prepared a good amount of it in our own laboratory because it was not commercially available in Italy, although at about that time it became available in U.S.A. as a solvent of nitrocellulose. To protect secrecy we baptized nitromethane with the name of Ergol. (By a strange coincidence this name was also used a few years later in Germany to indicate any liquid pro- pellant.) We studied carefully its stability against mechanical shocks, which makes it very difficult to detonate, and its resistance to thermal decomposi- tion. We measured its vapor pressure up to 200 °C. We determined its thermal stability by dropping into baths of molten metal with increasingly higher temperatures small sealed capsules containing nitro- methane, so designed that they would explode only if thermal decomposition took place. The lower NUMBER 10 47 FIGURE 21.—General Crocco (1), Theodore von Karman (2), and the General's son (3) at the Fifth Volta Conference, 1935. explosion limit was found to be around 400°C. Having, in 1933, reached the conclusion that nitromethane is an easy substance to handle,' we tested its gasification in the apparatus of Figure 18, where it behaved according to the theoretical pre- dictions. Encouraged by these results and by the lack of any adverse indications, my father and I started contemplating other uses for the interesting prop- erties of nitromethane. There was, indeed, very little interest among Air Force officials in the future of rockets. However, Italy had captured some high altitude airplane records, and high altitude flights were fashionable. Consequently we thought of ap- plying nitromethane to the design of an engine which could produce power in the absence of air. The monocylinder engine, shown schematically in Figure 19, was designed and built. It was in- tended to work on the two-stroke cycle, whereby the nitromethane was injected in the residual gases of the previous cycle recompressed to a high tempera- ture during the compression stroke. Fortunately high-pressure fuel injection systems for Diesel engines had become commercially avail- able in those years, thanks to the Bosch Company. For demonstration purposes, a hand-operated Bosch injection system was first tested in the apparatus shown in Figure 20. The gas generator B, similar to, but smaller than, that of Figure 18, was fed by the pump P and discharged its gases on a small turbine 48 SMITHSONIAN ANNALS OF FLIGHT T, connected to an electric generator G. Although the overall efficiency of conversion was certainly well below 1 percent, for the high sponsoring offi- cials this device was more convincing than any scientific chart or presentation. Next the mechanically driven injection system to be used in the engine of Figure 19 was tested in an apparatus designed to permit the atomization characteristics of nitromethane to be observed. It was unfortunate that the otherwise excellent Bosch injection pumps available at the time were designed for Diesel oil and hence did not require any positive lubrication. During a particularly long run there was an explosion which made the thick pump walls literally disappear under my very eyes. I missed that day my chance of being inscribed on the roll of victims of propellant research, escaping with rela- tively few injuries; after a month in bed I could walk again. Dr. Corelli, who was standing next to me, was also slightly injured. The cause of the explosion was attributed to the removal, after a few minutes of operation, of the lubricating oil film from the pump plunger, with resulting seizure of its surface. The corresponding hot spots acted as ignition sources for the closely confined, high-pressure nitromethane. Indeed, it was easy to reproduce the explosion under con- trolled conditions. Because at the time no injection systems with positive lubrication were available, the high-pressure injection process for nitromethane was judged too hazardous, and was abandoned. A few years later Bosch produced such a positive lubrication system for gasoline engines. In the following years we designed other mono- propellant engines of different types. Let me only mention a compressed-gas engine to be used in underwater propulsion, utilizing the gases pro- duced in a nitro-methane-plus-water gas generator, and a spark-ignition 4-stroke-cycle piston engine to be operated by nitromethane vapor alone. This lead to a series of interesting studies and experi- ments on the possibility of a decomposition-flame propagation in the vapor itself. But this reseach is too far removed from rockets to allow more than this passing mention. I also would like to mention our renewed in- terest, in those years, in bipropellant combinations, and the interesting studies of Dr. Corelli on the properties of tetronitromethane as an oxidizer. The Fifth Volta Conference, of which my father was president (see Figure 21), provided an opportunity for many of the leaders in the story of high-speed flight to meet. However, generally speaking, the interest of the Italian sponsoring offices in rocketry was at a dead end. It was only after the war, in 1947, that I became again involved in experiments on the applications of nitromethane to rocket propulsion for the Direc- tion des £tudes et Fabrication d'Armements of the French Ministry of Defense. It was there that I suc- ceeded in operating a rocket chamber of appreci- able dimensions and relatively small L*, using inward radial injectors uniformly distributed on the cylindrical wall of the chamber. After 1949 I continued this work for some time in the United States, with the authorization of the French author- ities and the collaboration of the Aerojet-General Corporation, where outward radial injection from a central pylon was also successfully tested. But all this is modern rocket history and not part of my father's pioneering activity in the field of Italian rocketry—the subject of this presentation.* NOTES Under the title Rannie issledovaniya v oblasti raket i raketnogo topliva v Italii, this paper appeared on pages 34-55 of Iz istorii astronavtiki i raketnoi tekhniki: Materialy XVIII mezhdunarodnogo astronavticheskogo kongressa, Belgrad, 25- 29 Sentyavrya 1967 [From the History of Rockets and Astro- nautics: Materials of the 18th International Astronautical Congress, Belgrade, 25-29 September 1967], Moscow: Nauka, 1970. 1. General Crocco was 90 at the time of this presentation and died the following 19 January 1968. See "Ex mundo astronautico," Astronautica Acta, vol. 14, no. 6 (October 1969), p. 689.—Ed. 2. Luigi Crocco, "Instruction and Research in Jet Propul- sion," Journal of the American Rocket Society, no. 80, March 1950, pp. 32-43. 3. Gaetano Arturo Crocco, "Sulla possibilits della naviga- zione extra atmosferica, Rendiconti Accademia nazionale del Lincei (Rome), ser. 5, vol. 32, part 1, 1923, p. 461; "Possibilita di superaviarione," Rendiconti Accademia nazionale del Lincei (Rome), ser. 6, vol. 3, 1926, pp. 241, 363; "II proiettile a reazione," Revista aeronautica, vol. 2, no. 3 (March 1926), pp. 1-4; "La Velocita degli aerei e la superaviarione," Revista aeronautica, vol. 2, no. 9 (September 1926), pp. 3-52; "Un paradosso del propulsore a reazione," Rendiconti Accademia nazionale del Lincei (Rome), ser. 6, vol. 3, 1926, p. 370. 4. An interesting account by Theodore von Karman of General Crocco's Presidency of the Fifth Volta Congress of High Speed Flight in 1935 and von Kdrnran's meeting with General Crocco's son is given in his The Wind and Beyond, written with Lee Edson (Boston: Little, Brown and Company, 1967), pp. 216-23.—Ed. 1. My Theoretical and Experimental Work from 1930 to 1939, Which Has Accelerated the Development of Multistage Rockets Louis DAMBLANC, France Preamble Preamble to Mr. Louis Damblanc's paper by L. Blosset, Deputy Director of the National Space Research Center (France). Mr. Louis Damblanc, who is 78 years old today (26 September 1967)—Chevalier of the Legion of Honor, recipient of the International Astronautics Prize of 1935 and the Gold Medal of the National Research and Inventions Office, and a Laureate of the Society for Encouragement of Progress—may be considered as the father of our present multistage rockets. Passionately interested in research in fields as different as aeronautics, astronautics, mechanics, and optics, his inventions have aroused the interest of scientific and technical circles, especially in the years before World War II (multistage rocket,1 rotary-wing airplane,2 engine with variable stroke and compression 3). During the thirties, Louis Damblanc invented, built, and flight-tested the powder-propelled multi- stage rockets which carry his name: The "Louis Damblanc" two- and three-stage rockets, of which each stage became automatically detached after the end of combustion. This development is the subject of the paper given by him here, and it is in this field that he is the great pioneer, recognized as such by both the French and United States gov- ernments. As a matter of fact, the International Patent In- stitute of the Hague has confirmed the world pri- ority of the French patent granted to Louis Dam- blanc on 26 June 1936 for automatically separable multistage rockets: "self-propelled projectiles of which the propellant charge is distributed into several superimposed combustion stages along the longitudinal axis of the rocket." This priority also holds true for his corresponding U.S. patent of 12 April 1938, which covers the marine two-stage Terrier rocket. Another Damblanc United States patent covers the test stands designed by him. Dur- ing World War II, both patents were sequestrated by the U.S. Alien Property Custodian under the "Trading With the Enemy Act," but as a result of the Franco-American (Blum-Byrnes) agreement con- cluded after the war, the French Ministry of Fi- nance and Economic Affairs in July 1965 granted Damblanc an indemnity for the use of his two patents by U.S. authorities, thus again confirming the priority of his inventions. In addition, his research on rockets has been crowned with success in several other areas: he succeeded in "taming" black powder by increasing its combustion time and by obtaining smooth com- bustion; he increased the strength of rocket bodies by using the most modern materials available at the time (such as the magnesium alloy, called at the time Metal M1 or "Electron"); he perfected a means of stabilizing rockets in flight; and, above all, he obtained effective separation of stages by means of a process of fuse rings of his own invention, and by this means successfully launched numerous multistage rockets. Within the context of this Symposium on the History of Astronautics, it is fitting that the Centre National d'ELudes Spatiales, of France, pay homage to a researcher who has contributed to the early development of space research and who deserves a 49 50 SMITHSONIAN ANNALS OF FLIGHT place of honor among the pioneers of space ex- ploration.4 Introduction On my own initiative and having remained to the very end the only technician working on this great problem—the design, production, laboratory experimentation, static tests and numerous flight tests of rockets of my invention—I was able during the years prior to 1939 to develop a number of rocket prototypes which, at that time, were in the forefront of progress. From the beginning, I used only solid fuels, in particular, fine-grain slow-burning mine powder. This I succeeded in "taming" by markedly increas- ing the combustion time and by burning parallel layers at a strictly constant speed. With the help of the Central Pyrotechnics School of Bourges, I was able to obtain blocks of a composite powder, strongly compressed and homogeneous, which always gave the best results. As often as possible, I chose for my tests sunny days without appreciable wind. My theoretical study and an analysis of the combustion process may be found in my first book, Self-propelled Rockets, published in April 1935.5 My second book was published on 11 January 1938. The use of my compressed powder with internal nozzle enabled me to obtain the specific gravity of 1.48, as compared with 0.83 for uncompressed black powder. Average combustion speeds always proved to be remarkably constant. They varied, depending on the type of Louis Damblanc rocket, between 13 and 20 mm per second. The combustion always took place in successive concentric layers around the internal conical area. During all our tests up to 1939, the combustion of the charge was always constant and stabilized in each stage. From the very beginning of my research, I was struck by how little care had been given to the construction of the rocket. In my large rockets, we employed ordinary sheet metal from 2 to 3 mm thick, singly-riveted along the whole length. Use of this primitive structure was feasible only because of the very small pressures developed during com- busion. The very frequent overpressures, on the order of 10 times ordinary pressure, resulted in immediate failure. The self-propelled rockets de- signed by me developed pressures 60 times greater in ordinary operation. The test firing took place at the Bourges Firing Ground (Central Pyrotechnics School). A large number of experiments were made at the test bench and in vertical launches, because angular launching over a very extensive ground did not permit the rockets to be recovered easily. Development of Test Means for Automatic Axial Pressure Recording My test stand, shown diagrammatically in Figure 1, was designed to provide the following: v*$77w; 1. Measurement of the maximum thrust value of a rocket by the compression of a previously calibrated spring. FIGURE 1.—General diagrammatic view of the rocket test stand. Tube (1) constitutes the combustion chamber intended to receive the rocket, open at the upper end to let the com- bustion products escape and including a bottom (2) intended to receive and transmit the reactive forces resulting from rocket operation. The forces are found by measuring the elastic strains on a coil spring (3). Every stress on the bottom (2) results in depression of spring (3) and in displacement of tube (1), transmitted to a pointer (13) inscribing the corresponding curve on drum (15) driven by a clockwork mechanism. NUMBER 10 51 2. Measurement of thrust at all combustion mo- ments by automatically recording the stress curve as a function of time: r. f(t)dt 3. Measurement of time by use of a pendulum (Figure 2) which beat the seconds and was clearly visible at a distance. In order to re- ference pendulum oscillations easily on film, the rod L was extended by another rod L1 with a large disc D, white and bordered in black, on its top. For all tests of the experimental rockets, I filmed in slow motion the incandescent jet caused by powder combustion. The sound recording of the "blow" enabled me to observe that the sound in- tensity remained constant during a very large frac- tion of the incandescent part of the total combustion time. This coincided remarkably with the long horizontal part of the curve representing the height FIGURE 2.—One-second-beating pendulum, serving as metro- nome, and filmed, together with the test stand, in operation. *-o -; FIGURE 3.—Slow-motion recording (left) of the incandescent jet from powder combustion. The band on left side of film shows the amplitude of sound intensity. Right: Filmed com- bustion recording shows the displacement of the reference rod integral with the movable tube. 52 SMITHSONIAN ANNALS OF FLIGHT FIGURE 4.—Equipment for launching the Damblanc self-propelled variable-inclination rockets (1939), and (right) more compact and simpler launching equipment for smaller diameter rockets (the man in the photo is Damblanc's faithful assistant Maillard). variations of the incandescent part of the flame. Figure 3 shows frames from the film of a bench test, on which can be seen the amplitude of sound intensity and displacement of the recording pendu- lum. On film I could observe that the vertical flame progression had a remarkably sharp outline. Our recordings were made by means of a camera provided with a sound-recording device. Two dynamic loudspeakers were interconnected. One, placed near the rocket, served as a microphone while the other, in front of the recorder, was used as the receiver. In this way, I was able to co- ordinate temperature and sound recordings. The receiver-recorder was equipped with a device to translate sound into light beams and to synchron- ously record it on the photographic film. The Launching Apparatus The variable-inclination apparatus shown in Figure 4 (left) I designed, built, and experimented with as early as 1937. Thanks to these experiments I could, in 1939, proceed succesfully to the launch- ing of my largest rockets (133-mm diameter) with several automatically separable stages. For launch- ing smaller rockets, I used the simpler and more compact apparatus shown in Figure 4 (right). Rockets Tested, 1935-1939 Thanks to my carefully preserved files, the fol- lowing list may be given: 1. Two-stage 35.5-mm-diameter rockets. The first stage was of steel, the second of magnesium, called Metal Mx or "Electron," which represented at that time the summit of metallurgical technique. Weight of illuminating flare without parachute, 500 g; firing angle, 90° and altitude as measured by theodolite, 2,150 m, corresponding to a range of 6,325 m. 2. Rocket of the same diameter but, for the first time with both stages made of magnesium. The altitude reached exceeded the one for the previous rocket but could not be measured because of cloudy weather. All these tests were officially certified. This rocket, very light and extremely easy to handle, was tested on 24 October 1939, and was intended to be mass-produced in several thousand units. The same was true for the rocket of 72 mm diameter tested at the same time. Its first stage was of duralumin and the second, of Metal Mi (Electron)—a great novelty at the time. This rocket could carry an illuminating flare weighing 10 kg up to an altitude of 500 m. Obviously, on the eve of the Second World War, the practical applica- tions were subordinated to combat requirements. 3. Magnesium-alloy (Mx) rocket of 88-mm diam- eter and a total length of 2.20 m. It had three stages and triangular stabilization fins. Figure 5 shows this as well as a two-stage, 55-mm-diameter rocket with different stabilization tail planes for each stage. These were successfully launched on NUMBER 10 53 FIGURE 5.—Three-stage rocket of magnesium alloy, 88-mm diameter, 2.20-m long, with triangular stabilization fins. Two-stage rocket, 55-mm diameter, with different stabilization tail planes for each stage. Right: Successful launch of one of these at Bourges in July 1938. the Bourges firing ground in July 1938, as shown in Figure 5. 4. My 133-mm rockets, the most powerful ones built in France at that time, of which the structure was obtained by cutting off a shell-body. Capable of transporting heavy loads, its drift did not ex- ceed 2 percent. It was built in three stages, each automatically separable, after complete combus- tion of the lower stage, by means of a device I had invented. Between 1935 and 1939, I launched 360 rockets of my invention. Listed below are a few of my other special devices from that period: • Takeoff booster for the Air Ministry. • "Ballistic wheel" of large diameter, built and successfully experimented in 1938, for the under- water study of self-propelled Damblanc rockets. • Short-distance postal rocket, of which the launch- ing device is shown in Figure 6. • Highly successful experiments of vertical support of steel wire ropes by self-propelled systems (anti- aircraft). • "Signal rockets" used in the Sahara in 1938, rising above sand fogs which in this region, may be found at altitudes of 1,200 m and above. In them I used a special color to prevent their being confused with the stars, which are quite bright in tropical countries. • "Mooring-support" rockets with a range of 500 m. • Self-propelled supply rocket with the payload recovered by parachute. My principal invention is indubitably that of multistage rockets whose length was shortened as the propellant was consumed. I applied for my French patent on 7 March 1936, my application in Belgium having taken place earlier—9 March 54 SMITHSONIAN ANNALS OF FLIGHT 12 J2 FIGURE 6.—Launching equipment for Damblanc short-distance postal rocket. This drawing apparently prompted the article "Big Guns May Speed Mail Rockets" (Popular Science, vol. 128, April 1936, p. 41).—Ed. 1935. My French patent, 803,021, granted on 29 June 1936, protected effectively the following claims: 1. Radial combustion propagation of the powder grain with axial space. 2. Complete combustion before separation of each stage. 3. Separation by fuse ring and stage separation by explosion. 4. Consumable rocket bodies. 5. Multistage rockets. 6. Use of light metals and alloys for the casings of rocket stages. Figure 7 shows a page from my French patent 803,021. The corresponding patent taken out in the United States, "Self Propelling Projectile," United States Patent 2,114,214, dated 12 April 1938, contains 7 claims and is a literal reproduction of my French patent. Similar patents were also granted me in Germany, the United Kingdom, and Japan. The International Patent Institute, The Hague, the highest court in this matter, in its consultation of 22 December 1960, cites as the first in the world my French patent 803,021 of 29 June 1936, which covers self-propelled projectiles "of which the pro- pellant charge is distributed into several super- imposed combustion stages along the longitudinal axis of the rocket." FIGURE 7.—Three cross-sections of rockets as shown in French patent 803,021, 29 June 1936. In addition, on 11 May 1939, I took out French patent 859,352, covering the replacement of screws by tapped sleeves in order to assemble two adjacent components of a multistage rocket. A preliminary very important trial of my test stand at the National Office of Research and In- ventions succeeded completely, as may be seen on the official test report of 30 May 1936, shown in the appendix. Another of my French patents that marked an important advance, 802,422, of 26 February 1936, concerned the novel design of the rocket test stand I have described above. The corresponding United States patent 2,111,315, of 15 March 1938, was en- titled "Force measuring devices for rockets." My two United States patents were sequestrated by the Government of the United States during World War II. After the war, as a result of the Franco-American Blum-Byrnes agreement,0 I re- quested and obtained in 1965 indemnity for the use of my patents during that period. In 1935,1 received from the Societe Astronomique de France the REP-Hirsch Astronautics prize, an NUMBER 10 55 international award, in recognition of my role as a pioneer.7 NOTES Under the title Teoreticheskie i eksperimental'nye raboty vo Frantsii mnogostupenchatym raketam (1930-1939), this paper appeared on pages 25-33 of Iz istorii astronavtiki i raketnoi tekhniki: Materialy XVIII mezhdunarodnogo astro- navticheskogo kongressa, Belgrad, 25-29 Senlyavrya 1967 [From the History of Rockets and Astronautics: Materials of the 18th International Astronautical Congress, Belgrade, 25-29 September 1967], Moscow: Nauka, 1970. 1. Louis Damblanc, "Les Fusee autopropulsives a explosifs; essais au point fixe; Application des resultants, experimentaux a l'etude du mouvement," L'Aerophile, vol. 43, July and August 1935, pp. 205-09 and 241-47; and "I razzi autopro- pulsive ad esplosivo," Rivista Aeronautica, vol. 7, January 1936, pp. 87-100.—Ed. 2. L. Damblanc, "Les Helicopteres et les laboratoires d'essais," I'Adrophile, vol. 28, 15 October 1920, pp. 314-315; and "The Problem of the Helicopter," Journal of the Royal Aeronautical Society, vol. 25, January 1921, pp. 3-19.—Ed. 3. L. Damblanc, "Sur un disposif applicable aux moteurs d'aviation pour reduire les pertes de puissance en altitude," Comptes Rendus de l'Academie des Sciences, vol. 180, 14 April 1925, pp. 1161-64; and "Du moteur d'aviation au moteur d'automobile," VAerophile, vol. 35, 15 March 1927, pp. 67-70.—Ed. 4. Damblanc died in early December 1969. A necrology appeared in the 10 December 1969 issue of Le Parisien Libere, written by Louis Lamarre, "Louis Damblanc, le pere des fusees a etages est mort" [Louis Damblanc, The Father of Staged Rockets Is Dead].—Ed. 5. Louis Damblanc, Les Fusees autopropulsives a explosifs (Paris: Ministere de l'Education Nationale, 1935).—Ed. 6. "Memorandum of Understanding Between the Govern- ment of the United States of America and the Provisional Government of the French Republic Regarding Settlement For Lend-Lease, Reciprocal Aid, Surplus War Property, and Claims," pp. 4175-78, in United States Statutes at Large, vol. 61 (in 6 parts), p. 4, International Agreements Other Than Treaties (Washington, D.C.: United States Government Print- ing Office, 1948).—Ed. 7. "The History of the REP-Hirsch Award," Astronautics, No. 34 (June 1936), pp. 6-7 and 13. Appendix Official test report, dated 30 May 1936, from the French National Office of Scientific and Industrial Research and of Inventions. The test was carried out on a body including two metal armatures, with dimensions, diameter and thickness conforming to the actual model, those two armatures being connected by an assembly con- forming to the invention. AUTHENTICATION 1. The total assembly had the rigidity and solidity permitting it to be handled under normal con- ditions with complete satisfaction. 2. The rocket body was placed in accordance with the experimental conditions (climbing flight). The upper body was restrained; the lower body included a sufficient powder charge for ensuring lining of the rocket up to the connecting as- sembly level. This powder charge was ignited and after 7 seconds, the time corresponding exactly to the total combustion duration of the charge, the lower body became detached sharply and fell on the ground, the connecting assembly having melted only when the ignited powder came into contact with it. The Director of the National Office of Research and Inventions (Signed) J. L. Breton Member of the Institute Robert H. Goddard and the Smithsonian Institution FREDERICK C. DURANT III, United States Robert Hutchings Goddard, American rocket theorist, inventor, and experimenter was associated with the Smithsonian Institution for nearly thirty years. Throughout this period Charles G. Abbot, fifth Secretary of the Smithsonian Institution, was the prime contact, supporter, mentor and trouble- shooter to whom Goddard unfailingly looked for support and technical assistance in his experimental efforts. The writer has been privileged since his associa- tion with the Smithsonian Institution in 1964 to have access to a remarkable archival collection of Dr. Robert H. Goddard's reports, correspondence, and photographs as well as physical specimens of his rockets. To study these materials is inspiring, for clearly their author was a brilliant, capable, and imaginative man. The first contact between Goddard and the Smithsonian Institution was by letter, dated 27 September 1916. At that time Goddard was thirty- two years old. Born (5 October 1882) and educated in Worcester, Massachusetts, Goddard received his B.S. degree from Worcester Polytechnic Institute in 1908 and his M.S. and Ph.D. degrees from Clark University in 1910 and 1911, respectively. He con- ducted research at Princeton University (1912-13) on a post-doctoral fellowship, but for reasons of health returned to Worcester. Majoring in physics throughout his educational training, Goddard (Figure 1) embraced the academic life and taught physics, first as an instructor and soon after as professor, when he was not engaged in research on rockets. In 1916 Charles Greely Abbot (1872- 1973) was Assistant Secretary of the Smithsonian under Secretary Charles Doolittle Walcott (1850- 1927). As an astrophysicist, Abbot had pioneered in solar measurements and observations. Goddard's letter was lengthy—six and one-half pages. In it he wrote: For a number of years I have been at work upon a method of raising recording apparatus to altitudes exceeding the limit for sounding balloons; and during the last two years I have tried-out the essential features of the method at the Labora- tory of Clark University with very gratifying results. These experiments are now completed, and I feel that I have settled every point upon which there could be reasonable doubt. Incidentally, I have reached the limit of the work I can do single-handed; both because of expense, and also because further work will require more than one man's time.1 He mentioned the military potential of his device as a long-range weapon (it will be recalled that Europe was then embroiled in World War I) but added that, "exclusive use of the device for war- fare would, I am certain, be a loss to science . . Goddard summarized his theoretical calculations and the results obtained experimentally firing smokeless powder in chambers with a tapered ex- haust nozzle. In these tests jet velocities as high as 8,000 feet per second had been achieved. He listed his patent coverage, received in 1914, of multiple rockets powered by both single and re- petitive-firing solid propellants as well as by pump- fed liquid propellants. Goddard postulated that a one-pound payload could be fired to an altitude of 200 miles and recovery of apparatus achieved by a parachute. He went on: I hesitate to give my conclusion regarding the possibility of sending small masses (under what I feel sure are realizable conditions) to very much greater heights than those I have just mentioned.2 He asked if the Smithsonian might have his pro- posed method and techniques reviewed by a sci- entific committee and, if favorably received, that funds might be found to support further research. Goddard closed by stating: 57 58 SMITHSONIAN ANNALS OF FLIGHT FIGURE 1.—Robert H. Goddard at blackboard in physics laboratory, Clark University, 1924. I realize that in sending this communication I have taken a certain liberty; but I feel that it is to the Smithsonian Institution alone that I must look, now that I cannot continue the work unassisted.3 When Goddard's letter was received on 29 Sep- tember, Secretary Walcott was on travel and the letter was brought to Abbot as Acting Secretary. There is no doubt that Abbot was immediately intrigued. For Walcott he wrote a longhand sum- mary of the letter, directing attention to Goddard's specific requests and saying— I believe there are several meteorological problems ... of great interest which might be solved by aid of the device, as: 1. What is the composition of the highest atmosphere? 2. How does temperature fall at great altitudes? * On 11 October, Secretary Walcott acknowledged receipt of Goddard's letter, indicating interest and inquiring as to the level of funds Goddard was seeking.5 Goddard responded with a summary of his approach on a year's program at an estimated cost of 5,000 dollars.6 More details were requested 7 and Goddard sent copies of his patents and a lengthy manuscript; he also offered to come to Washington to brief a deliberating committee.8 On 18 December Abbot wrote to Secretary Walcott that he had examined the manuscript carefully as well as the patent specifications, concluding— I believe the theory is sound, and the experimental work both sound and ingenious. It seems to me that the character of Mr. Goddard's work is so high that he can well be trusted to carry it on to practical operation in any way that seems best to him. I regard the scheme as worth promoting.9 An independent assessment of Goddard's concept and technique was solicited from the Bureau of Standards in Washington. Dr. Edgar Buckingham, a theoretical physicist there, agreed with Abbot, albeit more cautiously, and closed by expressing "hope that the Smithsonian Institution will see fit NUMBER 10 59 to help Mr. Goddard in developing his inven- tion . . . ." 10 On the basis of the two favorable opinions, Secretary Walcott wrote Goddard on 5 January 1917 to announce that the Smithsonian Institution had "verified the soundness of your theoretical work and accuracy of the numerical data," that they were "favorably impressed with the ingenuity of your mechanical and experimental dispositions, the clear- ness of your exposition, and . . . the value of that which is proposed . . . ." Accordingly, a grant of "$5,000 from the Hodgkins Fund" was approved. Reports were to be made "yearly or oftener if notable progress" was made. A part-payment check for 1,000 dollars was enclosed.11 Thus began the long relationship between C. G. Abbot of the Smithsonian Institution and the physics professor, Robert H. Goddard. Secretary Walcott asked Dr. Abbot and Dr. Buckingham to serve as a two-man advisory committee regarding Goddard's activity.12 Thus all correspondence to the Smithsonian was routinely brought to Abbot's attention. Two months later, on 6 April 1917, the United States entered World War I. On 11 April, Goddard wrote to the Smithsonian and pointed out the possible value of his rocket concept to long-range bombardment because of its lightness of weight, compared with artillery, and its ease of mobility.13 Abbot wrote to the Secretary that he believed that the proposition had merit and "quite warrants the War Department in spending a sum not exceeding $50,000 under his direction for experiments."14 On 20 August, Goddard wrote, "if the apparatus has any possibilities as regards warfare ... it should be ready for the drive by the Allies which will probably take place next spring." 15 Thus was displayed the strong faith of Abbot and Goddard in the long-range rocket concept. On 22 January 1918 Walcott and S. W. Stratton, Direc- tor of the U. S. Bureau of Standards, jointly signed a letter to the Chief Signal Officer, U. S. Army, enclosing a report on Goddard's research activities signed jointly by Abbot and Buckingham10 and requesting a sum of $10,000 for purposes of devel- opment. Based upon Goddard's successive-firing rocket, expectations might be: Weight (pounds) Range (miles) 7 120 Rocket 3 4 Total 9 32 Warhead 3 Propellant 3 25 Since Walcott was Chairman of the Military Com- mittee of the National Research Council in addition to his Smithsonian position, this request carried some weight and Signal Corps support was forth- coming.17 The next ten months saw a great increase in tempo. Goddard employed seven men, equipped a shop and laboratory at Clark University, struggled to obtain special powder formulations from the Hercules Powder Company, procured special gun steels, supervised modifications to rocket apparatus design, performed tests, reduced data, and wrote reports.18 The Worcester draft board was on the point of drafting a key workman into the Army. Goddard appealed to the Smithsonian for assistance.19 Abbot, after much effort managed to obtain a draft classifi- cation change.20 Goddard required special powder- testing gauges (crusher blocks).21 Abbot obtained them.22 An industrialist attempted to force revela- tion of Goddard's work in order to produce the military rockets himself. The Smithsonian came to the rescue.23 There were other incidents. On relocating test work to Pasadena, California in June 1918 the staff increased, as did Army funds.24 But now, a new shop had to be equipped and staffed, special steels and tubing obtained, more special formulations of powder, and so on. The Smithsonian Institution monitored all expenditures and Abbot sought to obtain by request or demand each of Goddard's requirements. By 10 July "excellent" results were obtained on a tube-launched rocket.25 When the Smithsonian received the telegram requesting ord- nance and ballistics experts to come and observe progress, Abbot made the arrangements.20 One of Goddard's young assistants, Clarence N. Hickman, lost parts of fingers of both hands in an accident while handling explosive detonators.27 Hospitalization and medical payments required much correspondence but this too, was settled satisfactorily.28 By late September 1918, firing tests were re- quested by the Army Ordnance Corps at Aberdeen Proving Ground, Maryland.29 On 6 and 7 Novem- 60 SMITHSONIAN ANNALS OF FLIGHT FIGURE 2.—Goddard inserts 3-inch rocket in lightweight tube launcher. Demonstration tests were made at Aberdeen Proving Grounds, 6-7 November 1918. ber, one-, two-, and three-inch rockets (launched from lightweight tubes, see Figure 2), a double- expansion trench mortar, and a multiple-charge repeating rocket (Figure 3) were demonstrated.30 Witnesses agreed that the weapons systems showed great promise.31 However, the war ended two days later. National reversion to peacetime activities stopped further development of these wartime ap- plications of Goddard's rockets and interest by the military.32 Returning to Clark University at Worcester, Goddard attempted to settle his accounts and wind up the intensive effort of the past few months. On 7 April 1919 Goddard wrote suggesting that publication of the concept of his original high altitude rockets might be desirable as a Smith- sonian paper.33 Some highly sensational and irre- sponsible newspaper articles on the military work of Goddard had appeared and it seemed desirable to set down facts.34 Abbot replied in the affirma- tive; 35 Goddard made some modifications to his manuscript, and it was published by The Smith- sonian in December 1919 with the cautious title "A Method of Reaching Extreme Altitudes." 3e Seven- teen hundred and fifty copies of this 69-page paper were printed. Little notice might have been given to the pub- lication if the Smithsonian had not issued on 11 January 1920 a press release which invited atten- tion to Goddard's speculations on a shot to the Moon.37 This portion of the paper was essentially an extrapolation of the main techniques described, and in it the concept of a moon shot was under- played. Typically, however, Goddard had made experimental tests of the minimum quantity of NUMBER 10 61 flash powder which might be observed if set off on the dark part of a new moon.38 The newspapers leaped on this small element of the report, ignoring the carefully delineated ele- ments of the rocket theory and its promise for upper atmospheric research. Goddard wrote to Wal- cott on 19 January 1920: Although there may very likely be ultimate possibilities of even greater interest than the proposed flash powder experi- ment—for it is difficult to see the limits of application of a perfectly new method—people must realize, nevertheless, that real progress is a succession of logical steps, and not a leap in the dark, and hence it is very important that, for what- ever reason interest is taken in the work, adequate support and interest should be given the preliminary investigations.39 Shifting from repeating-charge solid propellants to liquid propellants in September 1921, Goddard experimented with liquid oxygen.40 Striving to handle this cryogenic substance with lightweight apparatus (Figure 4) was an enormous challenge which occupied much of his attention over the next few years. On 16 March 1926, after successful static tests, he achieved his (and the world's) first flight with a liquid propellant rocket.41 In a report to Abbot on 5 May 1926, he wrote: In a test made March 16, out of doors, with a model of this lighter type, weighing 5% lb empty and IO14 lb loaded with liquids, the lower part of the nozzle burned through and dropped off, leaving, however, the upper part intact. After about 20 sec the rocket rose without perceptible jar, with no smoke and with no apparent increase in the rather small flame, increased rapidly in speed, and after describing a semicircle, landed 184 feet from the starting point—the curved path being due to the fact that the nozzle had burned through unevenly, and one side was longer than the other. The average speed, from the time of the flight measured by a stopwatch was 60 miles per hour. This test was very sig- nificant, as it was the first time that a rocket operated by liquid propellants traveled under its own power.*2 The necessary lightness of design of Goddard's liquid oxygen and gasoline rocket (Figure 5) was achieved with remarkable skill. The thrust of the motor was about 9 pounds,43 apparently, because on firing, the rocket remained in the launch stand for some seconds. When the weight became less the rocket lifted slowly on its short historic journey. Although the rocket flew to an altitude of only 41 feet and landed at a distance of 184 feet, it may be considered a bench mark in flight history as FIGURE 3.—Multiple-firing, solid propellant rocket. Cartridges contained in magazine at center are propelled forward by gas pressure into firing chamber resulting in repeating, intermit- tent thrust. 62 SMITHSONIAN ANNALS OF FLIGH'. FIGURE 4.—Goddard with 1926 design liquid oxygen-gasoline rocket. Rocket motor is at top. Right, world's first successful liquid propellant rocket before launching on 16 March 1926. great as that of Orville Wright who in his first flight achieved a distance of only 120 feet. Mrs. Goddard was recording this event with a motion picture camera which held only 7 seconds of film, and unfortunately the film had run through before takeoff! Collecting all the pieces, Goddard reduced the length of the nozzle, increased the throat diameter, added some braces to the structure and flew the apparatus again on 3 April.44 Two more attempts were made on 13 and 22 April but the motors burned through the walls.*5 By 4 May the apparatus was rearranged (Figure 6), the motor being placed in its more classic position at the lower end to eliminate the need (and weight) of the long pro- pellant line tubing in the earlier design.46 It was this rocket which Goddard later gave to the Smith- sonian Institution and is on display today, together with large rockets of the later Roswell period. No public news release was made of the 16 March 1926 success. Goddard realized that further reduc- tion in the weight of his small rocket was not feasible. In the hope of a spectacular demonstration, he set at once to build a much larger rocket.47 The designed motor thrust was 20 times greater, about 200 pounds, the rocket stood 109 inches tall, weighed 76 pounds dry and carried about 80 pounds of propellants. Pressurizing gas was obtained by pass- ing liquid oxygen around the combustion chamber. A spin-table, operated by a 50-pound drop-weight, was incorporated to give the rocket spin-stabiliza- tion at launch. In a static test on 20 July 1927 there were problems involving initial pressurization and combustion chamber failure.48 An alcohol burner was added to aid liquid oxygen pressuriza- tion at start conditions but in a test on 31 August, NUMBER 10 63 FIGURE 5.—Modification of rocket design in, now classic, con- figuration: motor at rear, surmounted by liquid oxygen and gasoline propellant tanks. Rocket is on exhibit at Smith- sonian Institution. although a thrust of more than 200 pounds was obtained, the injector head burned through.49 To reduce costs and construction effort Goddard now turned to a medium-sized rocket design of thrust equivalent to about 40 pounds. Components were simply designed and easily replaced. Test work on rockets of this general size continued for nearly three years. Two more flights were achieved on 26 December 1928 50 and 17 July 1929.51 On the latter flight a thermometer and barometer, together with a camera to record data at zenith were carried as payload.52 All these flights were conducted on a farm at nearby Auburn, Massachusetts. Because the loud noise resulted in unwelcome publicity53 and alarmed local authorities,54 test work was shifted to the U. S. Army artillery range at Camp Devens, Massachusetts.55 Once again the Smithsonian paved the way with letters to the Army that secured the necessary permission.50 At this point substantial financial support became available from Daniel Guggenheim, a wealthy and philanthropic New Yorker who had been support- ing development of aeronautics at the request of his son Harry F. Guggenheim. Colonel Charles A. Lindbergh had personally visited Goddard in No- vember 1929 and had been impressed by potential developments of rocket power.57 At Lindbergh's suggestion,58 Guggenheim agreed to sponsor God- dard's efforts.59 Officials of the DuPont Company served as additional technical advisors to Guggen- heim. Meanwhile, the Carnegie Institution in Wash- ington in December 1929 advanced $5,000 to the Smithsonian for Goddard's continuing research.60 With the Guggenheim support, Goddard was able to increase significantly the size and scope of his work.01 Moving to Mescalero Ranch at Roswell, New Mexico,61 privacy and adequate supporting facilities permitted him to devote full effort to developing the many elements of sounding-rocket design which he had conceived. Such items included gyro stabilization, steering-jet vanes in the rocket exhaust as well as aerodynamic flaps, gas generators and turbopumps for propellants, improved injector heads, film cooling of combustion chambers, valv- ing, igniters, launch controls, and parachute re- covery.62 Goddard recognized that although Abbot would continue as a member of the Guggenheim advisory committee his work would no longer be under the direct support of the Smithsonian Institution. To Abbot he wrote: I am deeply appreciative of the support of the Smithsonian has given this rocket work, from its start as a bare idea with little experimental verification, in 1917. I am so particularly grateful for your interest, encouragement, and far-sightedness. I feel that I cannot overestimate the value of your backing, at times when hardly anyone else in the world could see anything of importance in the undertaking.63 As it turned out, however, Abbot continued his close and friendly relationship until Goddard's untimely death on 10 August 1945. For example, when Goddard's basic 1914 patents were about to expire in 1931,01 Abbot obtained sponsorship for a special bill in Congress.65 Military support of such a bill was necessary. However, the Army Ordnance Corps declared that "no immediate or near future use of rockets for ordnance purposes seems probable."6G The Navy, just as short- sightedly, declared that if rocket development were more public greater progress in national defense 64 SMITHSONIAN ANNALS OF FLIGHT could be expected. Thus Abbot reluctantly wrote a half-dozen letters acknowledging the viewpoints of the military, requesting withdrawal of the bill from committee action and to Goddard informing him of the lack of interest in his work.67 In 1932, at the depth of the world financial depression, Guggenheim funds became unavail- able.68 Goddard returned to Worcester and resumed teaching at Clark University.69 He wrote to Abbot asking if the Smithsonian might find 250 dollars for specific tests aimed at reducing weight of rocket designs.70 Abbot found the money 71 and next year on 2 September, Goddard wrote: It made possible work which will save much time when the development is continued later on a larger scale, and without it things would have been stopped completely.?2 If Abbot occasionally expressed impatience with Goddard's penchant for becoming fascinated and diverted by compelling and burgeoning new tech- nical concepts, his interest was obviously sincere and in the hope of successful demonstration of high-altitude rocket flight. When Goddard wrote to Abbot on 4 September 1934 73 that major funds had been resumed from the Daniel and Florence Guggenheim Foundation, Abbot replied: May I urge you to bend every effort to a directed high flight? That alone will convince those interested that this project is worth supporting. Let no side lines, however promising, divert you from this indispensable aim . .?* On 1 April 1935 Goddard mentioned in a letter to Abbot: You may be interested to know that I followed your advice last fall, and am glad I did so. I had planned on new con- trols, stabilization, and a large light model all at once. It seemed necessary to do this, as the time was so short. I see now that I might have worked the whole year without having much in the way of flights to show for itJ5 When special problems of technical logistics arose, such as supply of liquid oxygen and importing special equipment from abroad, it was to Abbot and the Smithsonian that Goddard turned for help. It was in recognition of this relationship and fully appreciating the historical importance of his work that on 2 November 1935 Goddard,76 on the strong urging of Guggenheim and Lindbergh,77 sent a complete 1934 Series A rocket to the Smith- sonian. Goddard asked that it not be placed on exhibition until requested by him, or in the event of his death, by Mr. Harry F. Guggenheim and Colonel Charles A. Lindbergh.78 Goddard's wishes were respected. When it arrived, the box containing the rocket was bricked inside a false wall in the basement of the Smithsonian to be exhumed and placed on display after World War II. On 16 March 1936 the Smithsonian published the second of Goddard's papers, entitled "Liquid- Propellant Rocket Development," covering his re- search at Roswell from July 1930 to July 1932 and from December 1934 to September 1935.79 Whereas the 1919 paper had concerned itself with the theory of rocketry and its potential, the 1936 paper de- scribed progress made, established priority on the world's first liquid propellant rocket flight, work on gyro-stabilization, static firings and flight tests to 7500 feet, and future plans to reduce weights to a minimum. There was one further relationship between Goddard and the Smithsonian which is revelatory both of the man and his view of the Smithsonian Institution. During the period 1920-1929 Goddard wrote four unsolicited reports dated March 1920, August 1923, March 1924, and August 1929. In these reports, which he asked the Smithsonian not to make public, Goddard revealed his dreams of interplanetary flight and how it could be accom- plished by rocket power. He also displayed his trust and confidence in the Institution knowing that the reports would be safeguarded and pre- served. Never publicly released until published in The Papers of Robert H. Goddard, they set forth the principles of lunar and interplanetary flight, and they document Goddard's interest in and ap- preciation of the potential of rocket power as well as his fertile, creative imagination. His March 1920 report, of 23 typewritten pages, is entitled "Report on Further Developments of the Rocket Method of Investigating Space."80 Part I, "Investigation Conducted without an Op- erator," we would today entitle "Scientific Satellites and Space Probes." In this section Goddard sug- gests the value of photographing the Moon and FIGURE 6.—a, Larger rocket, developing about 200-lb thrust, tested 20 July 1927; b, "Hoop Skirt" rocket, flown 26 December 1928; c, payload-carrying rocket, flown 19 July 1929; d, ba- rometer and camera to photograph atmospheric pressure at zenith (rocket also carried alcohol thermometer). NUMBER 10 65 66 SMITHSONIAN ANNALS OF FLIGHT planets, the use of gyros and flight-path correction by small rocket motors, an ablating reentry heat shield, tracking of vehicle on reentry, communica- tion with planetary extra-terrestrials, and sets forth the advantages of liquid hydrogen and liquid ox- ygen as ideal propellants. In Part II, "Investigations Conducted with an Operator" (today we would say "Manned Space Flight"), Goddard considers man essential for landing upon and taking off from planets. The use of retro-rockets on lunar landings and tangential atmospheric drag on re- turn to Earth are mentioned as well as a launch vehicle with a desirable mass ratio of 0.93. Launch takeoff weights of 100 to 250 tons for lunar landings are given. A section is devoted to the advantages of producing liquid hydrogen and liquid oxygen on a planet if water of crystallization were available from the soil. Solar energy would be used "except possibly on Venus." Goddard states, "The best location on the Moon would be at the north or south pole with the liquefier in a crater, from which the water of crystallization may not have evaporated, and with the [solar] power plant on a summit constantly exposed to the Sun. Ade- quate protection should, of course, be made against meteors, by covering the essential parts of the apparatus with rock." Goddard goes on to discuss the advantages of shortening the time of journey by the use of electric propulsion. A solar powered turbogenerator with a mirror collector 500 feet square is discussed, as are methods of producing an ionized jet of gas, and accelerating it electrostatic- ally. Both positive and negative ions would be produced to prevent space charge effect. Techniques of producing ions are discussed and experiments performed at Clark University in 1916-17 are cited. Goddard concludes in his report that "it is believed that an appeal for public support is justifiable." The August 1923 report to the Trustees, Clark University, "Principles and Possibilities of Rocket Developed by R. H. Goddard," is eight pages long.81 The first four pages contain a documentary sum- mary of his work to that date and elements of the March 1920 report. The remaining pages are de- voted to a discussion of Herman Oberth's Die Rakete zu den Planetenrdumen (Munich and Berlin: R. Oldenbourg, 1923) and of the many design elements which Goddard had suggested previously and had treated experimentally. In March 1924 Goddard sent to the Smithsonian a nine-page "Supplementary Report on Ultimate Developments."82 It represents, in the main, the results of further thought and study on the various aspects of interplanetary flight he had speculated about four years earlier in the March 1920 paper. In it he treats of propellant mixture ratio with excess hydrogen to reduce combustion chamber temperature and discusses suggestions for hydrogen and oxygen tank arrangements, the rotation of tanks (for stability), considerations of temperature and stress in tank design, a 1200-pound manned "observation compartment," selection of the "most economical acceleration" (about 4.8 g), atmospheric retardation, further considerations and calculations on soft landing on the Moon, low-density lithium as a construction material, and production of hy- drogen and oxygen by solar energy on the Moon and planets (with the exception of cloud-shrouded Venus). "In the case of Venus," Goddard suggests, "it is very likely that the wind could be used as motive power, as there appears to be good evidence of strong winds . . . ." The August 1929 "Report on Conditions for Minimum Mass of Propellant" 83 contains 13 pages, plus a 2-page Appendix and 4 pages of supple- mental notes referencing the March 1920 report and reflecting further study and new data. The first 8 pages propose a space-launch vehicle consisting of an airplane with transparent wings or a lighter- than-air ship with a transparent envelope within which is contained solar collectors and power plant. Goddard conceives of the possibility of accelerating air mixed with charged particles. Both electrostatic and electromagnetic repulsion are discussed. Accel- eration of the vehicle about the Earth would con- tinue until escape velocity had been achieved. To depress the trajectory at increasing velocity, God- dard suggests that it might fly inverted to give negative lift. Once escape velocity is achieved the vehicle would continue to accelerate at character- istically low-g ion-propulsion rates "for half the journey, decelerating for the second half, in order to reduce the time of transit to a practicable amount." Different techniques of ion accelerators are discussed. "In space,' writes Goddard, "the best method of propulsion, and the one involving least mass of ejected material, is undoubtedly the repul- sion of low speed electrons, and positive metallic ions, the latter by means of an electrode, an applica- NUMBER 10 67 tion for a U.S. patent on which has been filed by the writer." Three possible methods are suggested for "reaction against the air" electrostatically and electromagnetically. The next five pages list several dozen notes on rocket and space propulsion tech- niques contained in Goddard's notebooks, together with the dates recorded. The period covered is 1906-1912. Abbot's reaction to these four remarkable reports was not encouraging. In acknowledging the August 1923 report, Abbot wrote, ". . . very interesting reading. I am, however, consumed with impatience, and hope that you will be able to actually send a rocket up into the air some time soon. Inter- planetary space would look much nearer to me after I had seen one of your rockets go up five or six miles in our own atmosphere." 81 The March 1924 and August 1929 reports were each acknowl- edged with a single sentence stating that the material had been filed with the other papers relating to his experiments. One has the feeling that Abbot may have shaken his head gently while doing so. In summing up this review of the relationship between Goddard and the Smithsonian, the follow- ing points are clear: 1. The Smithsonian Institution, primarily through the efforts of Charles Greely Abbot, en- joyed 29 years of friendly association with Robert Hutchings Goddard and continually supported his work. 2. Professor Goddard was a man of great crea- tivity and inventiveness. A practical physicist, he displayed remarkable patience and persistence in his efforts to achieve successful sounding rockets for upper-atmosphere research. 3. Goddard's unpublished papers show that he dreamed of flight to the Moon and planets, and was caught up in the excitement of exploring the unknown. In a letter written in 1932 to H. G. Wells (Goddard, then 50 years old, had been strongly influenced by Wells' War of the Worlds) he revealed his inner drive by saying: How many more years I shall be able to work on the prob- lem, I do not know; I hope, as long as I live. There can be no thought of finishing, for "aiming at the stars," both literally and figuratively, is a problem to occupy generations, so that no matter how much progress one makes, there is always the thrill of just beginning ... .85 A special note of appreciation is given Mrs. Robert H. Goddard for her kindness in supplying detailed information not easily located, answering questions, and otherwise generously assisting the writer in understanding this remarkable man. NOTES 1. Robert H. Goddard to President, Smithsonian Institu- tion, 27 September 1916, in The Papers of Robert H. God- dard, edited by Esther C. Goddard and G. Edward Pendray (New York: McGraw-Hill Book Company, 1970), 3 vols., vol. 1, p. 170. (Hereafter cited as "Papers"). 2. Papers, 1:174. 3. Papers, 1:175. 4. Abbot to Walcott, 2 October 1916, Papers, 1:175. 5. Walcott to Goddard, 11 October 1916, Papers, 1:176. 6. Goddard to Secretary, Smithsonian Institution (C. D. Walcott), 19 October 1916, Papers, 1:177-78. 7. Walcott to Goddard, 29 November 1916, Papers, 1:179-80. 8. Goddard to Walcott, 4 December 1916, Papers, 1:180. 9. Abbot to Walcott, 18 December 1916, Papers, 1:181. 10. Buckingham to Walcott, 26 December 1916, Papers, 1:181. 11. Walcott to Goddard, 5 January 1917, and Goddard to Walcott, 9 January 1917, Papers, 1:190-91. 12. Walcott to R. S. Woodward, President, Carnegie Insti- tution of Washington, 1 June 1918, Papers, 1:232-33. 13. Goddard to Walcott, 11 April 1917, Papers, 1:194. 14. Abbot to Walcott, 14 April 1917, and Walcott to God- dard, 20 April 1917, Papers, 1:195-96. 15. Goddard to Walcott, 20 August 1917, Papers, 1:199. 16. Walcott and Stratton to Major General George O. Squier, U.S. War Department, 22 January 1918, and report on Dr. Goddard's device by Abbot and Buckingham, 22 January 1918, Papers, 1:210-12. 17. Papers, see footnote, 1:213. 18. These activities are described in great detail in Papers, 1:213-95. 19. Abbot to Walcott, "Report on Trip to Schenectady and Worcester," 19 March 1918. Robert H. Goddard-Smithsonian Institution Correspondence in the Archives of the Smith- sonian Institution (hereafter cited as "S I Archives"). 20. Walcott to Squier, 19 March 1918; Abbot to Walcott, 29 March 1918; Walcott to Maj. Gen. E. H. Crowder, 1 April 1918; Abbot to Goddard, 2 April 1918; SI Archives. 21. Goddard to Walcott, 1 May 1918, SI Archives. 22. Walcott to Squier, 3 May 1918; Capt. J. R. Hoover, Office of Chief of Ordnance, U.S. Army, to Walcott, 10 May 1918; SI Archives. 23. "Statement of C. G. Abbot," 31 May 1918, SI Archives. Goddard to George I. Rockwood, 24 January 1918, Papers, 1:212. Colonel E. M. Shinkle, Army Ordnance Department, to Rockwood, 27 May 1918; Memorandum by Brigadier Gen- eral C. McK. Saltzman, Signal Corps, for Acting Chief of Ordnance, 27 May 1918; Goddard to Walcott, 29 May 1918; Walcott to Squier, 31 May 1918; Papers, 1:228-32. 24. See note 12. Also Woodward to Walcott, 3 June 1918; Walcott to Goddard, 3 June 1918; Goddard to Abbot, 4 June 10. 68 SMITHSONIAN ANNALS OF FLIGHT 1918; telegram. Abbot to Goddard, 5 June 1918; Papers, 1: 233-34. 25. Telegram George E. Hale to Abbot, 10 July 1918; God- dard to Walcott, 15 July 1918; Papers, 1:246-48. 26. Goddard to Edmund C. Sanford, 15 July 1918; tele- gram, Abbot to Hale, 17 July 1917; Squier to Chief of Ordnance, 19 July 1918; Abbot to Goddard, 22 July 1918; telegram, Goddard to Abbot, 1 August 1918; Papers, 1:248-49. 27. Goddard to Walcott, 8 August 1918, Papers, 1:253. 28. Memorandum, Abbot to Walcott, 14 October 1918; Chairman, U.S. Employees' Compensation Commission, to C. N. Hickman, 10 October 1918; SI Archives. 29. Telegram, Abbot to Goddard, 23 September 1918, Papers, 1:288-89. 30. Program for Tests at Aberdeen Proving Ground, Pa- pers, 1:296-99. 31. Goddard to Walcott, 15 November 1918, Papers, 1:300- 301. 32. Lieutenant Colonel Herbert O'Leary, Army Ordnance Department, to Secretary, Smithsonian Institution, 19 No- vember 1918; Abbot to Goddard 26 March 1919; Papers, 1:302-3, 315-16. 33. Goddard to Abbot, 7 April, 1919, Papers, 1:320. 34. "Invents Rocket with Altitude Range 70 Miles; Ter- rible Engine of War Developed in Worcester by Dr. Robert H. Goddard, Professor of Physics at Clark in Laboratory of Worcester Tech, under Patronage of U.S. War Department," Worcester Evening Gazette (Massachusetts), 28 March 1919, Papers, 1:316. 35. Abbot to Goddard, 10 April 1919; Goddard to Abbot, 15 April 1919; Abbot to Goddard, 18 April 1919; Papers 1:322-23. 36. Smithsonian Miscellaneous Collections, vol. 71, no. 2, 69 pp., 10 pis.; reprinted in Papers, 1:337-406. 37. "New Rocket Devised by Prof. Goddard May Hit Face of the Moon; Clark College Professor Has Perfected Inven- tion for Exploring Space—Smithsonian Society Backs It," Boston Herald, 12 January 1920, reprinted in Papers, 1:406. 38. Papers, 1:393-95. 39. Goddard to Walcott, 19 January 1920, Papers, 1:410. 40. Goddard's Diary (hereafter cited as Diary), 11 July- 13 September 1921, Papers, 1:474. 41. Diary, 16-17 March 1926, Papers, 2:580-82. 42. Goddard to Abbot, 5 May 1926, Papers, 2:587-90. 43. Papers, 2:588. 44. Diary, 1-11 April 1926; Papers, 2:584-85. 45. Diary, 13 ApriI-5 May 1926; Papers, 2:586-87. 46. Diary, Papers, 2:585. 47. Goddard to Abbot, 29 June 1926, Papers, 2:597-98. 48. Diary, 20 July 1927, Papers, 1:620. 49. Diary, 31 August 1927, Papers, 2:621. 50. Diary, 24-26 December 1928, Papers, 2:651-53; Goddard to Abbot, 3 January 1929, Papers 2:654-55. 51. Diary, 3-17 July 1929, Papers, 2:667-68; Description of Flight of 17 July 1929, Goddard's Notebook on Experiments, Papers, 2:668-73. 52. Goddard to Abbot, 18 July 1929, Papers, 2:674-76; Abbot to Goddard, 20 July 1929, Papers, 2:678. Memorandum to Associated Press by Smithsonian Institution, 20 July 1929, Papers, 2:679-81. 53. "Goddard Experimental Rocket Explodes in Air; Clark Professor Making Tests on Auburn Farm," Worcester Evening Gazette, 17 July 1929, reprinted in Papers, 2:673; "Moon Rocket-Man's Test Alarms Whole Countryside—Blast as Metal Projectile Is Fired Through Auburn Tower Echoes For Miles Around, Starts Hunt for Fallen Plane, and Finally Reveals Goddard Experiment Station," Boston Globe, 18 July 1929, reprinted (along with other newspaper clippings) in Papers, 2:674. 54. Robert E. Molt, State Fire Inspector, to George C. Neal, State Fire Marshal, Boston, 25 July 1929, Papers, 2:682. 55. Goddard to Abbot, 26 July 1929, Papers, 2:682-84. A summary of Dr. Goddard's experimental notes for the test at Camp Devens is presented in Goddard, Rocket Develop- ment: Liquid Fuel Rocket Research 1929-1941 (hereafter cited as Rocket Development), Esther C. Goddard and G. Edward Pendray, editors (Englewood Cliffs, New Jersey: Prentice-Hall, Inc., 1961), pp. 1-14. 56. The efforts which lead to the issuance of a license by the War Department for use of the Camp Devens Reserva- tion for rocket experimentation are detailed in Papers, 2: 685-710. 57. C. Fayette Taylor, Department of Aeronautical Engi- neering, Massachusetts Institute of Technology, to Goddard, 22 November 1929, Papers, 2:713; and Diary, 23-27 November 1929, Papers, 2:713. 58. The events of the eight months between Charles A. Lindbergh's initial meeting with Dr. Goddard and the subse- quent financial support by Daniel Guggenheim are described in Papers, 2:713-44. 59. Guggenheim to Wallace W. Atwood, 12 June 1930, and Atwood to Guggenheim, 13 June 1930, Papers, 2:744-45. 60. John C. Merriam to Goddard, 19 December 1929, and Goddard to Merriam, 26 December 1929, Papers, 2:726-28. 61. Atwood and Goddard to Abbot and other members of the Advisory Committee, 14 June 1930, Papers, 2:746; and statement released by Clark University "for publication in newspapers of Thursday, July 10, 1930," 9 July 1930, Papers, 2:752-54. 62. A summary of Goddard's experimental notes for the tests conducted in New Mexico is presented in Rocket De- velopment, pp. 15^46 and 57-215. 63. Goddard to Abbot, 28 May 1930, Papers, 2:742. 64. Goddard to John A. Fleming, 22 January 1931, and statement regarding the desirability of a reissue of U.S. Patents 1,102,653 and 1,103,503 from the standpoint of na- tional defense, 22 January 1931, Papers, 2:782-84. 65. H.R. 16451, House of Representatives, 21 January 1931, and H.R. 7174, House of Representatives, 8 January 1926, SI Archives. 66. W. H. Tschappat to Abbot, 6 February 1931, SI Ar- chives. 67. Abbot to Goddard, to W. W. Gilbert, to J. T. Robin- son, to R. Luce, and to Goddard, all 1 February 1931, SI Archives. 68. Telegram from Goddard to Atwood, 2 June 1932; At- wood to the members of the Advisory Committee on the Goddard Rocket Project, 14 June 1932; and Colonel Henry Breckinridge to Goddard, 16 June 1932; Papers, 2:830-32. 69. Diary, 28 June-2l July 1932, Papers, 2:833-34. 53. NUMBER 10 69 70. Goddard to Abbot, 5 August 1932, Papers, 2:837. 71. Abbot to Goddard, 25 August 1932, and Goddard to Abbot, 12 September 1932, Papers, 2:838-39. 72. Goddard to Abbot 2 September 1933, Papers, 2:865. Summaries of Dr. Goddard's experimental notes for the test conducted at Clark University, 1932-34, appear in Papers, 2:866-67 and 878-84. See also Rocket Development, pp. 47- 56. These activities were assisted by a grant from the Gug- genheim family of $2500 on 15 July 1933, Papers, 2:850-51 and 860. 73. Goddard to Abbot, 4 September 1934, Papers, 2:878. 74. Abbot to Goddard, 17 September 1934, Papers, 2:887-88. 75. Goddard to Abbot, 1 April 1935, Papers, 2:910-11. 76. Goddard to Abbot, 2 November 1935, Papers, 2:945. 77. Abbot to Goddard, 2 October 1935, Papers, 2:938-39. 78. See note 76. 79. Smithsonian Miscellaneous Collections, vol. 95, no. 3, 16 March 1936, 10 pp., 11 pis., 1 fig.; reprinted in Papers, 2:968-84. 80. Papers, 1:413-30. 81. Papers, 1:509-17. 82. Papers, 1:531-40. 83. Papers, 2:688-98. 84. Abbot to Goddard, 3 November 1923, Papers, 1:519. 85. Goddard to H. G. Wells, London, England, 20 April 1932, and Wells to Goddard, 3 May 1932, Papers, 2:821-23, 825. 77. 77. Giulio Costanzi: Italian Space Pioneer ANTONIO EULA, Italy Giulio Costanzi was born in 1875. Originally an officer of artillery of the Royal Italian Army he joined in 1911 the Battaglione Specialisti del Genio. This military corps, with its free and captive bal- loons, airships, and hydrogliders, was the nucleus of the Italian Air Force. Part of its facilities in- cluded a laboratory with wind tunnels and a towing tank. Costanzi, who had a university degree as a civil engineer, was in charge of this laboratory, which had been created by the well-known air and space pioneer Gaetano Arturo Crocco (1877-1968), who died on January 19 of this year [1968].x During World War I Costanzi was commander of a reconnaissance airplane squadron of the Italian Air Force. At the end of the war, as a lieutenant colonel, he headed the Experimental Station of the Air Force. In 1923, as a colonel, he joined the newly established independent Royal Air Force and was assigned various technical tasks. Later, he was technical assistant to the Air Force Minister and Professor at the Royal Air Force Academy in Caserta. In 1928, he resigned from the Air Force as a General and was appointed member of the Con- siglio di Stato. In 1938 he became President of the Registro Aeronautico Italiano, the Italian counter- part of the U.S.A. Federal Aviation Agency, and kept this official position until 1945. The author of several technical papers, he died at the age of ninety, in 1965. In 1914 Costanzi published in the Italian maga- zine AER,- a paper which can be considered the first Italian contribution to the study of space flight. Costanzi anticipated in a poetic and prophetic way some features and problems of space flight and also, though in a particular sense, the possibility of using nuclear forces for propelling spacecraft. Such a clear intuition of what was to happen more than forty years later is astonishing, and because the paper is rather short, it is translated in its entirety in the following paragraphs. It seems now that the heroic period of conquest of the air is near its end. When, in the not too distant future, men seeking great achievements, having flown the Atlantic Ocean and made round-the-world flights, look for new obstacles to overcome, the Promethean age of the conquest of the sky will begin. Is it really the time to consider escape from the Earth and to seek new colonies in space? As a matter of fact, it seems that the Earth has already become too narrow an area to contain such immense boldnesses, and that thoughtful auda- cious spirits can indeed seriously consider an undertaking born in the imagination of poets and novelists. These spirits wonder whether the barriers that forbid the undertaking of such a flight are really impenetrable, and whether the bonds that hold mankind on the narrow surface of our planet will be perennial. The planet's low, dense atmosphere ceases to be attractive. It is so dense that monstrous ships filled with hydrogen can float in it and heavy-winged machines can support themselves as on invisible rails. It is so impenetrable that only with enormous power consumption is it possible to reach a speed of a few hundred kilometers per hour. Yet only a short distance from us, just a few kilometers from our homes, it is possible to enter into free space that is endless, boundaryless, dragless, and nightless—where limita- tions to velocity do not exist and the sunlight flashes in a cloudless sky. Some men endowed with faith and energy, and belonging to the heroic generation which attained the previous goal, are preparing themselves for the new attempt. From Russia Riabouchinsky announces that he is going to begin some preliminary experiments in his laboratory at Koutchino. In France Esnault-Pelterie,3 one of the first conquerors of the air, has demonstrated on the basis of sound and thoughful calculations, that the present barriers, though severe and insuperable to-day, are of a mechanical and structural char- acter, which is to say that the possibility of a practical realization docs exist. Which kind of machines will prove capable of departing from the atmosphere into space, where no air exists to give 71 72 SMITHSONIAN ANNALS OF FLIGHT lift and life? Has there yet been conceived by human genius, or does it yet exist in embryo, an engine capable of thrusting a vehicle into the vacuum of space.? For many years it has been recognized that such an engine does exist. One need only to think of a machine-gun free to recoil on its own carriage while launching shells at great velocity in order to concieve of a propelling unit which would operate better in a vacuum. In any case, the principle of the so-called reaction engine is well known. The problem is to determine whether the energy required to attain this goal does exist, or whether we here face an insuperable natural barrier. mM It is known that the energy necessary to transfer a body from the surface of a star to infinity is given by L-K where A' is the universal gravitation constant, m the mass of body, M that of the star, and R the radius of the star. From this formula, it follows that a body on the Earth's surface, launched with a velocity equal to or larger than 11,280 m/sec, will not fall back but will continue traveling indefinitely. For a 1-kg body on the Earth, the energy to attain this velocity would be 6,371,103 kgm, equivalent to 14,970 cal. Now 1 kg of hydrogen-oxygen mixture contains a much smaller amount of energy, i.e. 1,420 cal-*; therefore I kg of such a mixture has not within itself the capability of transfering even a single gram of its own substance to infinity. On the other hand, 1 kg of radium, which contains 2,900,000,000 cal, would have an energy 194,000 times greater than the amount required of it. Esnault-Pelterie has shown that a body on the Earth subjected to a constant force greater than its weight and directed outwards would attain a velocity sufficient to make its propulsion superflous at an altitude approximately equal to an Earth radius. Let us analyze the order of magnitude of the energy in- volved if one were to transfer, for example, a body from the Earth to the Moon and bring it back again to Earth. Three phases are to be considered: First phase: the body accelerates up to an altitude of 5,780 km; then its velocity will be 8,180 m/s and the time spent 24 minutes and 9 seconds; Second phase: the engine is cut off; the body continues to move on account of inertia; at the moment where the attraction of both Earth and Moon become equal, the velocity will be reduced to 2,030 m/sec and the time spent will be 48 hours and 30 minutes; Third phase: the engine is accelerated in the opposite di- rection for descent onto the Moon; the time spent during this phase is 3 minutes and 46 seconds. The total elapsed time from departure will be 48 hours and 58 minutes, and that for return will be the same. During this return trip the engine will operate only 28 minutes, the time being the same both going and returning. Now let us assume that the vehicle weight is 1000 kg, of which 300 are consumable (this ratio is customary for present-day airplanes). A short calculation shows that the engine power should be 414,000 hp. Such a vehicle at the speed of 10 km/sec would spend 47 days and 20 hours to reach Venus and 90 days and 15 hours to reach Mars. The analysis of probable sensations of a space traveller during the trip deserves particular attention. Aside from difficulties arising from the temperature and space radiations, there exists a probably serious one of a physiological char- acter. At a distance of 5,780 km from the Earth the traveller will feel as though his weight was eleven tenths of his normal weight; this feeling, though unpleasant, will not be prejudicial to his organism. But, when, during the second phase, weightlessness occurs, he will have the feeling of falling with the vehicle which contains him. Then it would be necessary to replace the force of gravity by a constant acceleration of the engine so controlled as to provide an acceleration that will at every moment replace the loss of gravitational pull. This method would eliminate the above mentioned incon- venient, but would cause a progressive increase of velocity to 61,700 m/sec in the case of a lunar trip, with the advantage of reducing the required time to 3 hours and 5 minutes; but the required power would be 4,760,000 hp. Then, even though the above assumed 300 kg of propellant were dyna- mite, it would amount to -r^-o^jr of the propellant necessary; but if radium were used it would still be 433 times that required. Travelling at a constant acceleration, Venus could be reached in 35 hours and 4 minutes with a maximum speed of 643 km/sec and Mars in 49 hours and 20 minutes with a maximum speed of 883 km/sec. The order of magnitude of such velocities is that of the celestial bodies, and in order to obtain the necessary energy concentration at the start it would be necessary to seek them among atomic forces. If a 1000-kg vehicle had on board 400 kg of radium and we were able to extract from it the required energy, we would have available the amount of propellant sufficient to a round-trip to Venus; but this amount would be hardly sufficient for an analogous trip to Mars, always assuming a flight with constant acceleration. Thus the difficulties that prevent us from achieving this ultimate human dream are not beyond human reason, but are dependent only on the possibility of a practical realiza- tion of the necessary means. Having observed the prodigi- ously accelerated development of findings in the field of mechanics, we can therefore doubt but cannot deny such a possibility. On the other hand argument and speculation are useless and unfruitful. The world advances, driven by tenacious willpower rather than by words and formulae. Perhaps scientists will still be arguing when the first auto-meteor penetrates interplanetary space. Some comments on Costanzi's text seen appro- priate. His clear intuition as to the advantage, from an economical point of view, of flying at high alti- tudes, of the need for jet engines, and of the enormous propellant consumption required by space flight, is remarkable. NUMBER 10 73 As far as his considerations on Moon flights are concerned, it is to be noted that the escape velocity would not be reached, because the Moon is an Earth satellite and therefore is always subject to the Earth's attraction. Nevertheless, as is well known, the velocity necessary to fly to the Moon is very near, although less than, the escape velocity. The considerations on the second phase of the lunar trip seem not to be completely clear. The restarting of the engine during the third phase is probably intended to decelerate for descent onto the Moon, but Mr. Constanzi does not say this explicitly. The ratio of propellant to total weight in present-day spacecraft is much higher than that assumed by the author but was valid for the airplanes of his day. What is astonishing are the author's very clear conception of the physiological sensations that space travellers have experienced during the coast- ing flight, and his concept of creating artificial gravity by means of acceleration to eliminate it. In order to obtain this result, which the author considered necessary, flights without acceleration are not taken into consideration by him. Walter Hohmann (in 1925) had not yet shown the ad- vantages of following cotangential trajectories.5 It is not clear how the figure of 4,760,000 hpb for the required power was calculated. It would undoubtedly have been better to have spoken in terms of thrust, which is well known, than in terms of power, or to have considered energy instead of power, as the author did at the start of his paper. The author's intuition of the advantages offered by the use of atomic forces to make space flight easier is extraordinary indeed. In conclusion, though some inexactness is ap- parent, Costanzi's paper is a most interesting, valu- able, and ingenious anticipation of the many space events which have now taken place, more than forty years later. NOTES 1. Sec Luigi Crocco, "Gaetano Arturo Crocco, 1877-1968," Aslronautica Ada, vol. 14, no. 6 (October 1969), p. 689.—Ed. 2. Giulio Constanzi, "To Escape from The Planet," AER, no. 5, 1914. 3. Robert Esnault-Pelterie, "Considerations sur les resultats d'un allegemcnt indefini des moteurs" [Considerations on the Results of Indefinite Decrease in Weight of Engines], Journal de Physique Theorelique et Appliquee, ser. 5, vol. 3, March 1913, pp. 218-30. 4. Apparently Costanzi, basing his calculations on those of Robert Esnault-Pelterie, made a copying error in his original article, where he is paraphrasing Esnault-Pelterie. The correct value should be 3,860 calories. See page 222 of note 3, above, or page 296 of Andrew G. Haley, Rocketry and Space Exploration (Princeton, New Jersey: D. Van Nos- trand Company, Inc., 1958), which contains a complete English translation of Esnault-Pelterie's 1913 article (this is reprinted as an appendix to Paper 2 of this series).—Ed. 5. Walter Hohmann, Die Erreichbarkeit Der Himmelskor- per [The Attainability of Heavenly Bodies], Munich-Berlin: R. Oldenbourg, 1925. An English translation has been pub- lished by the National Aeronautics and Space Administration, Washington, D.C., November I960, as Technical Translation NASA TT F-44—Ed. 6. An explanation of this figure appears on page 230 of Esnault-Pelterie (see note 3), and on page 301 of the English translation thereof (see note 4), wherein Esnault-Pelterie explains the need for 4,760,000 hp as follows: The time used to reach the moon would be t = 3 hr 5 min. But in this new case, the work to be furnished, using the assumption of a 1,000 kg vehicle of which 300 kg are con- sumable, would reach 67.2 X 106 cal/kg of fuel, i.e., 131 times more than in the first case. Dynamite would be 47,300 times too weak, but radium would still be 433 times too powerful. As to the necessary power, it would be 857 X IP10 24,000 X 75 = 4.76 X 106 hp. If we now assume that this method of constant propulsion is used for voyages to the closest planets and investigate what the times and velocities would be, we find the maxi- mum velocity for Venus 643 km/sec for Mars 883 km/sec and the corresponding times for Venus 35 hr 4 min for Mars 49 hr 20 min Recollections of Early Biomedical Moon-Mice Investigations CONSTANTINE D. J. GENERALES, JR., United States The year was 1931. The place was Zurich. The protagonists were two students, one aspiring to become an engineer, the other, a physician. It was in the beginning of March when I decided to have my first lunch at the student cafeteria open to matriculants of the University of Zurich and of the Eidgenossische Technische Hochschule. I had just arrived from an intersemester vacation in Athens after having spent my sixth semester (third year) at the University of Berlin, and I had found quarters at 34 Scheuchzerstrasse overlooking the beautiful lake of Zurich. My decision to continue my medical studies at various university centers such as Athens, Heidelberg, Zurich, Paris and Berlin was not a random one but based on a pre- conceived plan to combine study and travel with attendance at lectures by professors of note in the various fields of medicine, e.g., Menge, Naegeli, Gougerot, Sauerbruch, His. As I was waiting in line at the cafeteria, I hap- pened to overhear a brief conversation in English behind me. At that time this was unusual since German and Schweizer Deutsch and some French were the most frequently spoken languages in that part of the country. Curious and eager to speak English again, I turned around and faced a tall blond chap who informed me that he had just arrived from Berlin. We lunched together. After the usual exchange of amenities, he unexpectedly turned the conversation to rockets, and of all things, of using them to get to the moon. He men- tioned Herman Oberth, the German genius of rocketry, and Goddard, the immortalized American rocket pioneer. This German lad was quite serious about space travel and especially, of getting to the moon. I professed ignorance about the subject, even barely recollecting the distance between Earth and the lunar satellite. My field was medicine and all my subjects and efforts were directed toward ob- taining a medical degree. I just could not see, as a young student, how rockets and getting to the moon were going to help me in taking care of sick people! The first conversation was quite brief, we finished our lunch and parted. Approximately two weeks later we met again by chance and the topic again reverted to the construction of rockets to get to the moon. To me, this whole thing, as I recall, seemed rather ridiculous, and I began making fun of my friend with "a one-track mind" until he reached into his pocket and pulled out a letter and asked me to read it. The envelope was postmarked Berlin. I remember staring at the indeciphrable equations pertaining to mathematical problems and solutions in rocket design and propulsion. I was dumb- founded and deeply impressed when I recognized the signature to be that of Professor Albert Einstein. The recipient of the letter that I held in my hand was my newly found friend, Wernher Freiherr von Braun. As I read the letter and listened to Wernher I became aware of the possibility of future space travel and realized that it was not as absurd as it had seemed at first. Remember, the year was 1931, two years before the founding of the famous British Interplanetary Society. The question immediately arose in my mind: what about man, can he with- stand all these unknown forces and new experiences while being propelled by a sheet of flame into the vastness of space with the contemplated rocket? Right then and there I realized the inescapable necessity for the interdependence of medicine and technology in this great venture and I became a convert to the idea of exploration of space and 75 76 SMITHSONIAN ANNALS OF FLIGHT space travel. I remember clearly my verbal reaction as I handed the letter back to Wernher with the caution, "Wenn Du zum Mond gehen willst ist es besser zuerst mit Mausen zu versuchen!" x While Wernher was thinking in terms of linear propulsion and linear acceleration, I suggested that we might experiment with some mice and simulate the accelerative force by rotating them. The g factor would be the same. The laboratory centrifuge, sec- ond in popularity to the microscope, was standard equipment in bacteriology. However, its basic con- struction and its short radius would not do. We needed a larger contraption. What was wrong with a wheel from my bicycle? Nothing! It was no prob- lem to attach the pedal to the dismantled front wheel, which had a tachometer. A dozen white mice were easily "borrowed" from the animal caretaker in the biology lab with no promise of return. At this time, we had no funds other than our monthly allowance. It was decided to use Wernher's room (Figure 1), as it was larger than mine, and so within a week's time, we were spinning mice arranged in four little hammock-like bags attached, 90° apart, to the perimeter of the FIGURE 1.—In a corner room of this house in Zurich, Switzer- land, biomedical space-oriented experiments were conducted in 1931 by students Constantine Generales and Wernher von Braun. bicycle wheel that was mounted on a stand. Thus, the centrifugal effect expressed in g's would be analogous to that experienced in rocket launchings. Years later, I discovered that a number of people had used the centrifuge principle experimentally. For example, Erasmus Darwin, a physician and grandfather of Charles, had reported the first ob- servation on the effects of centrifugal force on man.2 And a crude centrifuge had been used by a Dr. Horn from 1814-1818 at the Charite Hospital of Berlin a in an attempt to improve the state of mentally deranged patients. Also, I learned many years after our early experiments, the Wright brothers had used the lowly bicycle wheel to ac- quire aerodynamic data necessary for the construc- tion of their first airplane. We had no idea what the tolerance of the mice might be. In the beginning, after a few turns of the wheel, the poor mice, whose hearts you could feel pounding in the palm of your hand, were placed upon the table. They would not move. Were they frightened? But frightened mice ordinarily tend to run away! I nudged them and still they would not move. Their eyes were open and as they were lying on their side I noticed a very rapid lateral nystagmus. Only when the nystagmus began to subside did the little creatures start to move in ever widening spirals. Many of the mice succumbed to the very high "acceleration" forces (to 220 g's).4 Autopsies that I performed showed a displacement of the heart and lungs (Figure 2). There was bleed- ing from the intrathoracic, intraabdominal, and in- tracranial areas. All the organs in the chest and abdominal cavities, as well as the brain, were dis- placed and torn in varying degrees from the sur- rounding tissues. It was obvious that the force which we had achieved was far greater than the mice could tolerate. I noticed that in some cases, the entire cardiovascular system was disrupted. Were some of the milder effects transitory? Could they be prevented? Would permanent damage re- sult? A new area of investigation was opening up, that of g forces, whose limits had to be defined before man was to attempt to reach the moon. The investigations were proving very exciting. Right at the height of our activities, a dramatic incident occurred. A mouse accidentally slipped out of its cradle and was dashed against the wall leaving bloody stains at the point of impact. The next day (I believe it was the third day of our experiments), NUMBER 10 77 r FIGURE 2.—First biomedical documentation of space-travel- oriented studies. Photograph illustrates various degrees of damage in the paraffin-blocked histopathological stained slides of skull, brain, heart, and lungs of mice. we were not too surprised that the landlady who was not accustomed to the odor of small laboratory animals, noticed "the blood on the wall"; became infuriated; seized my notes as evidence of non- sensical cruelty and torture; and threatened to evict us and notify the police unless we immediately ceased these crazy experiments. A long time ago, about a century and a half, before our space-minded experiments, there had been another landlady in Avignon. She was more cooperative and indeed showed some courage. Her boarder, a Joseph Michel Montgolfier, had been gazing before a burning fireplace at an engraving depicting the siege of British-held Gibraltar by the allied French and Spanish land and sea forces. His eyes next wandered over to the fireplace and, as countless generations had before him, watched the smoke rise from the fire in the hearth. Now, why couldn't the besieged English leave by air, he mused. If clouds float in the sky, why not capture a cloud of smoke in a bag? He obtained an oblong bag of fine silk from his landlady and held the open end over some burning paper. The bag swelled into an awkward sphere and immediately sailed to the ceiling much to his satisfaction and her very great surprise.5 Thus, the first unmanned balloon ascension was conceived and aeronautical science was born in the western world. Now back to the two police-threatened chagrined students. We had no choice but comply with our nonscientific but meticulous landlady. And, at the same time, we were very sad about our first casualty, which was, to the best of my knowledge, the first fatality of biomedical research conducted under admittedly crude but nevertheless effective simu- lated space-flight conditions. As a redeeming meas- ure and to relieve our burdened conscience, we let loose the remaining lucky four mice in the fields to a happier life away from an institutional environ- ment. Thus ended the Zurich portion of our experi- ments. After continuing my studies in Paris in the autumn of 1931, at the Sorbonne, I resumed my experiments with a large centrifuge (50 cm.) and with the help of Helene, laboratory technician to Professor Milian, Chief of the Dermatology Clinic of the Hospital St. Louis, who prepared parafin sections for microscopic slides of the succumbed mice, I was able to show, for the first time, histo- pathologically, the effects of high g forces.6 Un- fortunately, my notes have not survived the usual ravages of time, but I still possess some of those original slides. During summer 1931, Wernher and I traveled to Greece in my Opel roadster (Figure 3), and after we returned in October I visited with Wernher at the Raketenflugplatz in the outskirts of Berlin and met Rudolf Nebel and Klaus Riedel who were engineering liquid-propelled rockets. There I had the opportunity of seeing one of the launchings of Mirak I which rose to over 1000 feet. It was a spectacular sight as the pencil-shaped rocket de- scended, a small parachute attached to its tail. I shall never forget how the four of us, Wernher, Nebel, Riedel, and I raced to the landing spot, crowded into my Opel. 78 SMITHSONIAN ANNALS OF FLIGHT It was that little Opel again that helped make history, for as Wernher wrote in the British Inter- planetary Society Journal: Early one beautiful July morning in 1932 we loaded our two available motor cars and set out for Kummersdorf which lay some 60 miles south of Berlin. As the clock struck five, our leading car with a launching rack containing the silver- painted Mirak II atop and followed by its companion vehicle [the Opel] bearing liquid oxygen, petrol and tools, encoun- tered Captain Dornberger at the rendezvous in the forests south of Berlin." The successful launching of Mirak II convinced the German Ordnance Department of the feasibility of the rocket as a missile as well as progenitor for space travel. Although our early experiments were unrefined in the face of today's sophisticated methods, the very high g's over the many minutes of exposure pro- duced for the first time scientific evidence as to what damage one might expect to unprotected living organisms. I noted cases of cerebral hemor- FIGURE 3.—Wernher von Braun and Constantine Generales, on a pleasure trip to Greece in 1931, photographed in the Saint Gotthard Pass, where the author's Opel became overheated and chunks of snow and ice had to be used to cool the motor. Upon our return, because I was to be in Paris, the car was left in Wernher's care for the use of the Raketenflugplatz experts—to further the cause of rocket research. Shortly after my return from Paris I painted the Opel red. Subsequently it was stolen while I was visiting my parents in the United States. rhage, pulmonary stelectasis, hemothorax, avulsion or dislocation of the eyeballs, and so on. To the green mind of this inquisitive and experimenting student, thoughts of presenting a paper disclosing these pathological findings, so completely unrelated to any orthodox discipline in the accepted medical curriculum of those days, never occurred. Finally, in June 1960, the results of these original investigations first appeared in a medical journal.8 Indeed, according to Dr. von Braun, it took 20 years for researchers in this and other countries to verify these results, and it wasn't until 1958 that I had an opportunity to present to Wernher several tissue slides of the mice as a memento of our early work (see Figure 4). Edward Diamond, senior editor of Newsweek, quoted Dr. von Braun as follows: This was probably the first experiment in space medicine. The Air Force has probably spent $7 million to find out what we learned.9 In 1959 I proposed to the NASA, and in 1962 to the U.S. Air Force, a centrifugal space-vehicle simulator or Biocyclothanathron (Figure 5), to simulate, on the ground, the many unique proper- ties of space flight.10 Many of today's centrifugal facilities have subsequently incorporated certain features of the Biocyclothanathron. It is of interest to note that in 1931, the same year our space-minded biomedical experiments were being performed, Karl Jansky was studying peculiar static noises from outer-space which gave birth to the new science of radio astronomy; Wiley Post was successfully completing the first round- the-world flight in his monoplane "Winnie Mae"; and an enthusiastic crowd, including von Braun and the author, was greeting Auguste Piccard in front of the Baur au Lac Hotel at Zurich, following his first stratospheric flight, on 27 May with Charles Knipfer, to 51,753 feet (15,786.5 m.), from Augs- burg, Germany, to Glazier, Austria. Incidentally, the Zurich-Paris research antedated my first flight experience in an airplane by two years. Thinking of this always reminds me of the quotation of Dr. M. P. Lansberg of Holland: Space flight is indeed many centuries the senior of aviation, consequently, it was space medicine that preceded aviation medicine and not vice-versa.n FIGURE 4.—Presentation by Dr. Constantine Generales to Dr. Wernher von Braun of the first biomedical-histopathological tissue slides from the mice used in their early experiments. Presentation took place during a testimonial dinner honoring Edward Teller and Wernher von Braun, 15 May 1958, New York City. FIGURE 5.—The Biocyclothanathron, or cosmic vehicle simulator, conceived by the author and designed for him by the consulting engineering firm of McKiernan and Terry Corporation, Dover, New Jersey. 80 SMITHSONIAN ANNALS OF FLIGHT NOTES 1. "If you want to get to the moon, it is better to try with mice first!" Parenthetically, I would like to mention the Moonbeam Mouse Project that was the realization, thirty years later, of the foregoing statement. This project was presented before the 155th Annual Convention of the Medical Society of New York at Rochester, New York, 12 May 1961. Its aim was to acquire as much physiopathologic data as possible from the moon for medical evaluation before the advent of man. The purpose was threefold: (1) to investigate the be- havior and effects of transplanted terrestrial life under physical lunar conditions, (2) to detect possible lunar micro- bial life, and (3) to study the effects of such captive hosts on the terrestrial germ-free rodent guests. It represented a re- fined inter-disciplinary study with multiple-channel telemetry of exquisite biomedical data for a predetermined length of time for recording respiration rate, body temperature, blood pressure, blood flow, red and white corpuscle count, also, determination of the gamma-globulin. Gamma-globulin itself is almost completely absent in absolutely germ-free bred mice. The mice themselves were to be contained in a special vehicle that would bore itself mechanically into the ground up to ten meters. The lunar soil was to be drawn into the specially designed capsule where the mice would be exposed to the radiation-free and temperature-constant subsurface lunar soil. The mouse-carrying capsule was to be thoroughly sterilized with ethylene oxide and to have a self-supporting ecology for a two-week life supporting period under the surface of the moon. Since mice do not catch colds, they would be spared the discomfort of Astronauts Walter M. Schirra, Donn F. Eisele, and Walter Cunningham. Coryza was noticed first by Schirra within the first 24 hours; later the other astronauts became infected during the 11-day orbital flight of the Apollo 7 capsule, 11-27 October 1968, using 100-percent oxygen at about 5 pounds pressure. Isolation of a period of 2-3 weeks would be medically sound before extended space flights. What happened to the "Moonbeam Mouse Project"? It died prematurely at the hands of a high NASA executive in the life sciences (1960). He could not foresee "how mice could survive in the moon's environment which does not have an appreciable atmosphere," even though the major details of propulsion, landing, life-support, telemetry, etc., were workable. It received, however, recognition by two world-renowned scientists: a NASA rocket engineer who com- mented that "this project could be of value for future manned lunar landings"; and a microbiologist of the Rocke- feller Institute, who stated that it "presents a great interest from both the biological and medical points of view. In brief, I would be inclined to regard your project as a neces- sary first step in the analysis of the ecological problems that will arise when terrestrial organisms enter into contact with the various aspects of the lunar environment." The project was not pursued further. See also C. D. J. Generales, "Selected Events Leading to the Development of Space Medicine," New York State Journal of Medicine, vol. 63, no. 9 (May 1963), p. 1310. 2. In his Zoonomia (1795), saying: Another way of procuring sleep mechanically was related to me by Mr. Brindley, the famous canal engineer, who was brought up to the business of a mill-wright: he told me that he had more than once seen the experiment of a man extending himself across the large stone of a corn mill, and that by gradually letting the stone whirl, the man fell asleep, before the stone had gained its full velocity, and he supposed would have died without pain by the continuance or increase of the motion. In this case the centrifugal motion of the head and feet must accumulate the blood in both extremities of the body, and thus compress the brain. 3. William J. White, A History of the Centrifuge in Aero- space Medicine (Douglas Aircraft Company, Inc., Santa Monica, California, 1964). 4. Generales, "Space Medicine and the Physician," New York State Journal of Medicine, vol. 60, no. 11 (1 June 1960), p. 1745. 5. Peter Lyon, "When Man First Left the Earth," Horizons, vol. 1, September 1958, pp. 114-28. 6. Erik Bergaust, Reaching for the Stars (New York City: Doubleday & Company, Inc., 1960), p. 59; and Project Satel- lite (New York City: British Book Center, Inc., 1958), p. 23; Wernher von Braun, "Reminiscences of German Rocketry," Journal of the British Interplanetary Society, vol. 15, no. 3 (May-June 1956), p. 128; "Constantine D. J. Generales, Jr.," Twenty-Fifth Anniversary Report, Harvard College—1954 (Cambridge, Massachusetts: Harvard University Printing Office), p. 429; "Space Medicine," in History of Medicine "An International Bibliography," The Welcome Historical Medical Library, vol. 27, no. 177 (April-May 1960); "Die Traene Der Ruehrung Quilt," Weltbild, Munich, June 2, 1958, p. 4; "Constantine D. J. Generales, Jr.," Explorers Journal, vol. 37, no. 4 (December 1959) p. 10; and "Mars- och Venus-skott at vanta nar som heist" (from page 1 of Stockholms-Tidningen, 16 August 1960), Explorers Journal, vol. 38, no. 4 (December 1960), p. 18. 7. "Reminiscences of German Rocketry," Journal of the British Interplanetary Society, vol. 15, no. 3 (May-June 1956), p. 129. 8. See note 4. 9. "His Eyes Are on the Stars," Saga, February 1961. 10. Generales, "The Dynamics of Cosmic Medicine," New York State Journal of Medicine, vol. 64, no. 2 (15 January 1964), p. 231. 11. Martin Lansberg, A Primer in Space Medicine (New York City: Elsevier Publishing Company, 1960). 10. 8 The Foundations of Astrodynamics SAMUEL HERRICK, United States Astrodynamics is defined in terms of celestial mechanics and of space navigation in its broadest sense: pre-Sputnik, including orbit determination and correction, as well as post-Sputnik, which adds control and optimization. Basically there are three areas of celestial me- chanics: 1. Mathematical celestial mechanics is concerned with the existence of solutions to defined and re- stricted problems in celestial mechanics. It prefers methods that have generality in the sense that they are applicable to other fields of mechanics as well as to a range of problems in celestial mechanics. But these methods tend to be restricted to a given type of problem: e.g., the elegant potential and Hamiltonian methods are limited to conservative and quasi-conservative forces. 2. Physical celestial mechanics is concerned pri- marily with the use of celestial mechanics in the determination of physical constants that are of interest to other areas of physics, especially geo- physics and astrophysics. 3. Astrodynamics, as we term the third area of celestial mechanics, is greatly interested in physical constants, but also in all other factors that con- tribute to accurate space navigation, such as inte- gration constants, integration procedures, singulari- ties, and indeterminacies. Astrodynamics makes fundamental use of the general methods of mathe- matical celestial mechanics, and also of special methods that fit particular real problems. But whereas mathematical celestial mechanics tends to pursue one solution to a conclusion, with maximum use of a particular class of elegant mathematical tools, astrodynamics seeks to develop all possible solutions for purposes of comparison and selection. Mathematical celestial mechanics is concerned with ideal problems involving motion in a theoretically simple framework; astrodynamics is concerned with fitting a theory to observation and to the coordinate systems of the real world, and so is concerned with precession, nutation, aberration, parallax, the re- duction of observations (electronic as well as opti- cal), and with all the force fields that are encoun- tered in real problems. General methods and tools (e.g., the method of least squares and Bessel's func- tions) have often come out of the particular solu- tions of these real problems. No "celestial mechanic" devotes himself ex- clusively to one of these areas, but his heart is likely to be in one of them, and his judgement less than clairvoyant in the others. I shall indicate some of the differences between the areas and their meth- ods in the following discussions of the historical development of astrodynamics before 1940. My own serious concern with astrodynamics and space navigation began when I was an undergradu- ate student at Williams College. Four letters from Dr. Robert H. Goddard survive to attest to my plan for graduate study in the area, to Dr. Goddard's encouragement, and to his kindliness in taking time to give it even when his own prospects were bleak. I quote from two paragraphs of one of his letters, dated 15 June 1932: . owing to the depression, the rocket project is being discontinued July first, and the matter of its being resumed later is an uncertain one. I cannot help feeling that a theoretical investigation such as you mention has advantages over experimentation during such times as these These letters encouraged me to proceed to graduate study under Armin Otto Leuschner, Russell Tracy Crawford, and C. Donald Shane, at Berkeley, where I developed a thoroughgoing devotion to celestial mechanics as well as to space navigation. 81 82 SMITHSONIAN ANNALS OF FLIGHT Early History Illuminates the Character of A strodynamics Physical celestial mechanics may be said to have begun with Galileo Galilei, Isaac Newton, and the laws of force and gravitation. Astrodynamics and mathematical celestial mechanics, on the other hand, date back at least to Heracleides of Pontus in the fourth century B.C. The Greek invention of epicycles and eccentrics was developed into a system by Apollonius of Perga in the third century and Hipparchus of Alexandria in the second century B.C. It was refined and published by Ptolemy of Alexandria in the second century A.D., and came to be known as the Ptolemaic system. It is generally assumed that the epicycle was discredited by Jo- hannes Kepler some 1500 years later, but in point of fact epicycles have persisted in astrodynamics down to the present day, and have extended their domain into other areas of science under the guise of Fourier series! Hindsight is a valuable tool in the history of science and serves to illuminate on the one hand the contemporary understanding and acceptance of an idea, and, on the other, its clarity and persistence. The historian of science is likely to emphasize the former; the scientist himself is understandably more interested in the latter. My own hindsight theory has been presented to my students over the past 20 years, and by them conveyed to others, but for the most part it has remained unpublished in the conventional sense (except in preprints of my reference work Astro- dynamics 1). Basically it asserts that history has been unjust to epicycles, and even to Nicolaus Coper- nicus. (Some historians have gone so far as to say that the system of Copernicus was just as cumber- some as the Ptolemaic system, and that Kepler was the real author of our modern heliocentric theory.) With hindsight we can see that there are in a planet's motion three kinds of deviation from uni- formity that confronted the Greeks and their suc- cessors, and required explanation by a "system" such as the Ptolemaic or the Copernican: 1. The annual or Copernican or retrograde de- viation, caused by the motion of the Earth around the Sun. 2. The elliptic or Keplerian deviation, explained in simple two-body motion by the discovery that FIGURE 1.—a, Ptolemaic, b, Copernican, and c, Keplerian systems. the relative orbit of the two bodies is an ellipse or other conic section. 3. The perturbed or Newtonian deviations, caused by the attractions of the planets and their satellites for one another. The Ptolemaic system explained all of these de- viations by geocentric deferents surmounted by epicycles piled upon epicycles (see Figure 1, in which the largest epicycle is the annual one, the second represents the elliptic ones, and the smallest represents the perturbed-deviation epicycles). Aristarchus of Samos, and later Copernicus, eliminated the first deviation by shifting the center of the system from the Earth to the Sun, but the remaining deviations of the Copernican system still had to be accounted for by epicycles. It is this fact that led to the dictum that the Copernican system is "just about as complicated as the Ptolemaic sys- tem." It may have appeared so to contemporary eyes, but in retrospect it is clear that the elimina- tion of the five annual planetary epicycles—that is, one epicycle for each of the five known planets, the total "population" as of that time—was a major simplification of the mechanics of the system, so that Copernicus unquestionably deserves the popu- lar recognition accorded his name. Kepler accounted for the second class of deviation by his perspicuous laws of planetary motion. It is this fact that has generally been credited with the destruction of the epicycle as a mechanical device. NUMBER 10 83 i° (p.*. S) But it should be recognized that there were per- turbed deviations still unaccounted for in the Kep- lerian system. These deviations are most conspicu- ous in the motion of the Moon around the Earth, but the observations of Kepler's time were suffi- ciently accurate to show evidence also of the mutual perturbations of Jupiter and Saturn. When New- ton's development of the law of gravitation made it possible to explain these perturbed deviations by mechanical means, the epicycles that had survived Kepler's onslaught were adopted into Newtonian mechanics. As a matter of fact, the basic epicyclic theory re-expanded to include even the elliptic deviations, thus rejecting the Keplerian system in favor of the Copernican system, whose handling of the elliptic terms by systems of epicycles (rechris- tened "Fourier series") proves to be simpler than the use of expressions in terms of Keplerian ellipses. In a sense this development may be noted as realistic astrodynamic replacement for a theoretical mathematical formulation. We may note that Fourier series, with arguments that are multiples of a single angle, are less flexible than the original "astrodynamic" concept of epi- cycles, in which noncommensurate arguments are used: consider, for example, the representation of the geocentric motion of Venus, assuming that Venus and Earth are both travelling in circular heliocentric orbits. The Ptolemaic development would require only one epicycle; the Fourier devel- opment would require a theoretically infinite num- ber of terms or epicycles. In modern perturbation theory we actually take account of the original epicyclic concept by combining several Fourier series that have arguments based upon different angular variables. Astrodynamics Illuminated by Modern Treatment of Parallax Recent developments in the treatment of geo- centric parallax illustrate the importance to astro- dynamics of physically real reference systems, and of the reduction of observations, as contrasted with developments in mathematical celestial mechanics, in which the reference system is idealized and ob- servations are only theoretically taken into account. Figure 2 shows how geocentric parallax enters into the observations. The position of the Sun is designated by S, that of the observed object by the FIGURE 2.—Effect of geocentric parallax on observations. cometary symbol "c£", the center of the Earth by E, and the observer by T (for Greek topos, place, and for the adjective topocentric). The dynamical posi- tion of c£ is defined by the vector r (i.e., the line segment of Sdr). The position of the Sun referred to the center of the Earth is specified conventionally by the "solar coordinates'' that are given in astro- nomical almanacs, i.e., by the vector R (in the figure, ES). The geocentric position of the observer is specified by rT (ET). Finally the topocentric posi- tion of the comet is specified by the vector p, which represents the topocentric distance (today the "range") p, right ascension a, and declination 8. Classically the topocentric right ascension and declination are corrected for geocentric parallax to what they would have been had the observation been made from the center of the Earth, so that we have a single triangle relating E, S, and c£. In some problems there is still justification for such a pro- cedure, but in preliminary orbit calculations based upon observations of a and 8 the parallax can be calculated only after a first approximation has given a value of p. Successive approximations of this character were standard practice in orbit deter- mination for a great many years more than should have been the case! There were clumsy experiments with the "locus fictus" which is shown in Figure 2 as the intersection of the line of T& with the line ES. When Gibbs became interested in the orbit problem (1889),2 largely in connection with his development of vector analysis, he was fortunately 84 SMITHSONIAN ANNALS OF FLIGHT ignorant of astronomical practice. Consequently he decided very simply to correct the solar coordinates or the vector R from the center of the earth to the observer, at the start of the problem, by subtracting the known vector rT, thus replacing the triangle ESc^by the triangle TScA We find in the literature that this thought had occurred previously to Challis (1848),3 and possibly to Leverrier (1855),4 but had not taken hold. In fact astronomers were slow to adopt Gibbs' simple solution to the parallax prob- lem until the much more recent contributions of Bower (1922, 1932),5 Merton (1925),6 Rasmusen (1951),7 and others. My own contribution to revised thinking in this area is associated with my work on my thesis 8 in 1935 and 1936 and with a mathematically oriented contribution of Poincare^ (1906).9 FIGURE 3.—Illustration of real problems of orbit deter- mination. Poincare^ had suggested a "second approximation" for the Laplacian method of determining orbits. In the Laplacian method three observations of a and 8 are numerically differentiated in order to produce velocities and accelerations in these angular coordi- nates (see Figure 3). The numerical differentiation ignores the higher derivatives in the first approxi- mation, and it was these that Poincare aimed to restore in his "second approximation." The Lap- lacian solution usually involves an assumption that the observer is travelling in a two-body orbit, and this assumption was uncritically accepted by Poin- care. But it is not the observer (T in Figure 3) who travels in a two-body orbit, nor is it even the center of the Earth (£ in Figure 3) but (to a high degree of approximation) it is the barycenter of the Earth- Moon system (B in Figure 3). Williams (1934)10 attempted to make the Poincare method work by correcting for geocentric parallax, but found that barycentric parallax ultimately prevented the proc- ess from converging. He did not attempt to apply Leuschner's (1913)X1 technique for complete elim- ination of parallax. William's work came to my attention when I was writing my thesis. In reviewing the matter I became aware that the "motion of the observer" has nothing whatsoever to do with the problem, but is only a mathematical fiction: the "observer" may actually be three differ- ent observers at three different observatories. Con- sequently I decided to assume that this fictitious motion is determined by the real motion of the object and by the further assumption that the higher derivatives of the observed angular coordi- nates were zero. These assumptions made it possible to carry the "second approximation of Poincard" to a successful "real" conclusion. These assumptions also made it possible to relate the basic first approximation of the Laplacian methods exactly to the first approximation in the methods of Gauss,12 Lagrange,13 and Gibbs,14 a relationship that is necessary to the development of criteria for the selection of method in "real" problems of orbit determination. Linearization in Astrodynamics One of the issues in astrodynamics that is still unresolved nearly three decades after 1939 is the use of linear methods in astrodynamics. Many linear methods based upon the work of Poincare^ have been brought back into celestial mechanics without realization on the part of Poincare^ or his successors that non-linear solutions to the problems considered not only exist, but have been in constant use! Never- theless some of the ideas have been provocative, and newer uses may be found for them. It seems clear at present that linear methods may be used after a basic non-linear integration is com- plete, especially to obtain partial derivatives, but that their use in the basic integration is suspect, and may be either erroneous or unnecessary or both. The basic geometrical equation used in the com- parison of a theory with observations is certainly in a category for which linearization is allowable, and I find that Stumpff (1931)15 and I (1940)16 NUMBER 10 85 were experimenting in the use linear combinations of the residuals before 1940. The equation is aL=p = r+R fcos 8 cos a L = J cos 8 sin a sin 8 where r is SE in Figure 2 and R has been corrected from ES to TS as discussed above. Stumpff had already proposed the use of residuals in two of the ratios between the three components of L, selected according to size, when I, having proposed residuals in the interdependent compo- nents themselves, realized the equivalence of the two proposals. Essentially their aim was the avoid- ance of successive trigonometric recalculations of a and 8 in comparisons of successive theories with the observations. The basic Stumpff concept, I found, could be extended to residuals in p or r or even to the "ratios of the triangles" used in preliminary orbit deter- minations by the methods of Lagrange, Gauss, and Gibbs. In Conclusion The foregoing remarks have been designed to give not a complete history of the pre-1940 founda- tions of astrodynamics, but rather samplings of these foundations that reveal the character of the subject, as it may be partially distinguished from the more purely mathematical developments of celestial mechanics. These samples nevertheless demonstrate again that universal principles and ideas tend to crop up independently in more than one time or place, that their excellence depends upon provability, and that they will be used when the time is ripe if they are continuous from sound antecedents. Subsequent decades were to build enormously on the pre-1940 foundations, and to expand them, in conjunction with new instrumentation, with new vehicles, and with searches for previously inaccessi- ble physical constants or for greater accuracy in relativity constants, the solar parallax, and other basic data of value both to physics and to precision space navigation. Series Expansions Preliminary orbit determination, perturbation theory, correction theory, all make effective use of series expansions of many kinds. The use of Fourier series (or epicycles) has been remarked upon in the foregoing. Power series now almost universally called the "f and g series" were developed by Lagrange (1783)17 for the equations and from the series for /= 1, 3 (with 0 replaced by 2) were developed the series for the "ratios of the triangles" referred to above. Gibbs (1889)18 reex- amined these expansions with his usual clear-sight- edness and contributed new expressions for the "ratios" that have been the most generally recog- nized of his contributions to orbit theory. Happily, he left for me (1940) the extension of his develop- ments to companion expressions, even simpler, for the determination of velocity components from three sets of position components.19 These expres- sions have made the Lagrangian method for deter- mining a preliminary orbit as effective as the Gaussian, but simpler. They enter also into orbit determinations that involve modern electronic ob- servations of "range-rate." NOTES On 21 March 1974 Dr. Samuel Herrick Jr. died. His obitu- ary was carried in The Washington Post of 25 March 1974. —Ed. 1. Samuel Herrick, Astrodynamics (London, New York: Van Nostrand Reinhold, 1971), vol. 1. 2. Josiah Willard Gibbs, "On the Determination of Elliptic Orbits from Three Complete Observations," Memoirs of the National Academy of Science, vol. 4, 1889, pp. 81-104; Ernst Friedrich Wilhelm Klinkerfues, Theoretische Astronomie, ed., edited by Hugo Buchholz (Braunschweig: Vieweg, 1912), pp. 413-18; and The Collected Works of J. Willard Gibbs (New York: Longmans Green, 1928), vol. 2, pt. 2, pp. 118-48. 3. James C. Challis, "A Method of Calculating the Orbit of a Planet or Comet from Three Observed Places," Memoirs of the Royal Astronomical Society, vol. 14, 1848, pp. 59-77. 4. Urbain Jean Joseph Leverrier's anticipation of the cor- relation of solar coordinates to the observer was once shown to the author by Ernest C. Bower, but he has not been able to find it for reference in this paper. 5. Ernest C. Bower, "On Aberration and Parallax in Orbit Computation," Astronomical Journal, vol. 34, 1922, pp. 20-30; and "Some Formulas and Tables Relating to Orbit Com- putation and Numeric Integration," Lick Observatory Bulletin, no. 445, vol. 16, 1932, pp. 34-45. 6. Gerald Merton, "A Modification of Gauss's Method for the Determination of Orbits," Monthly Notes (of the Royal Astronomical Society), vol. 85, 1925, pp. 693-731; ibid., vol. 86, 1926, pp. 150-51; ibid., vol. 89, 1929, pp. 451-53. Also 1. 86 SMITHSONIAN ANNALS OF FLIGHT see Russell Tracy Crawford, Determination of Orbits of Coinets and Asteroids (New York: McGraw-Hill, 1930), pp. 103-35. 7. Hans Qvade Rasmusen, "Tables for the Computation of Parallax Corrections for Comets and Planets," Pub- likationer og mindre Meddelelser fra K0benhavns Obser- vatorium, no. 155, 1951, pp. 3-7. 8. Herrick, "The Laplacian and Gaussian Orbit Methods," University of California Publication, Contributions of Los Angeles Astronomical Department, vol. 1, 1940, pp. 1-56. 9. Jules Henri Poincare, "Sur la determination des orbites par la methode de Laplace" [On the Determination of Orbits by the Method of Laplace], Bulletin Astronomique, vol. 23, 1906, pp. 161-87. 10. Kenneth P. Williams, The Calculation of the Orbits of Asteroids and Comets (Bloomington: Principia, 1934). 11. Armin Otto Leuschner, "Short Methods of Determining Orbits" (Second and third papers), Publication of the Lick Observatory, University of California, vol. 7, 1913, pp. 217- 376 and 455-83. 12. Carl Friedrich Gauss, Theoria motus corporum coelestium in sectionibus conicis solera ambientium [Theory of the Motion of the Heavenly Bodies Moving about the Sun in Conic Sections] (Hamburg, 1809); translated by Charles Henry Davis (Boston: Little, Brown, 1857). 13. Joseph Louis Lagrange (1736-1813), "Sur le probleme de la determination des orbites des cometes, d'apres trois observations" [On the Problem of the Determination of the Orbits of Comets from Three Observations], Nouvelle Memoire de I'Academy Royale des Sciences et Belles-Lettres de Berlin; Oeuvres (Paris: Gauthier-Villars, 1869), vol. 4, pp. 439-532. 14. See note 2. 15. Karl Stumpff, "Uber eine kurze Methode der Bahn- bestimmung aus drie oder mehr Beobachtungen" [On a Short Method of Orbit Determination from Three or More Observations), Astronomischer Nachrichten, vol. 243, 1931, pp. 317-36, and vol. 244, 1932, pp. 433-64. 16. See note 8. 17. See note 13. 18. See note 2. 19. See note 8. 12. Vladimir Mandl: Founding Writer on Space Law DR. VLADIMIR KOPAL, Czechoslovakia In the industrial city of western Czechoslovakia, Pilsen (Plzen), famous for its Skoda engineering enterprise and large breweries producing the famous Pilsner beer, Dr. Vladimir Mandl (Figure 1) was born on 20 March 1899 and there lived the major part of his life. He became a pioneer in astronautics in Czechoslovakia and, in particular, author of the first monograph on legal problems of outer space flights. FIGURE 1.—Dr. Vladimir Mandl (1899-1941). The family Mandl had lived in Pilsen for gener- ations. Vladimir's father, Dr. Matous Mandl, was an attorney and his son, though an engineering enthusiast since his youth, decided to follow his father's career. After studies at the Pilsner high school Vladimir entered the Czech Faculty of Law, Charles University of Prague, where he graduated on 21 November 1921. Following graduation, he first practiced for a short time at a district court in Prague and later in an attorney's office. In March 1927 he opened his own office in Pilsen. While still a student Vladimir Mandl developed a deep interest in legal theory, especially in private law. Between 1921 and 1926 he was a member of the seminar on civil law procedure directed by the distinguished Czech scholar Professor Vaclav Hora. In 1925 Mandl submitted an interesting report on problems of evidence to the first Congress of Czech- oslovak Lawyers. Later (1926), he wrote a mono- graph on Czechoslovak civil law regarding marriage. Finally, Mandl completed his specialization in civil law procedure by postgradual studies at the Uni- versity of Erlangen, in Germany, where he obtained a doctorate by his dissertation on the law of damages. Having qualified for the bar with such excellent scholarship, Vladimir Mandl was free to dedicate his energy to actual legal problems created by indus- trial and technological developments of the 1920s and 1930s. First, he published a series of essays on the legal aspects of motor vehicles. These he ampli- fied, in 1929, into a monograph on the subject. Simultaneously Mandl studied legal problems of aviation which was developing rapidly in the years following World War I. His enthusiasm was so great that he became a pilot. The result of Mandl's intensive work in this field was his study on air law,1 the first systematic treatise on this new subject writ- 87 SMITHSONIAN ANNALS OF FLIGHT ten in Czechoslovakia. Following a historical intro- duction, the author dealt first with the Czechoslovak air regulations. In the second part he considered some general problems of air law, such as liability arising from international air transport contracts, conflicts of law concerning aviation, customs, and insurance against damage caused by aircraft. The final chapter dealt with air warfare. Dr. Mandl submitted his book on air law as his advanced work in residence, hoping to gain a pro- fessorship at the Faculty of Mechanical and Elec- trical Engineering, Czech Technical University of Prague. Documents deposited in the Archives of the University of Prague demonstrate that Mandl ful- filled admirably all the conditions required and that his scholarly work and knowledge were highly re- spected by the accreditation commission.2 On 20 September 1932 the Czechoslovak Minister of Edu- cation confirmed the decision of the Board of Pro- fessors of the Faculty concerning the granting of venia docendi to Dr. Vladimir Mandl for the sub- ject, Law of Industrial Enterprises.3 Although ap- pointed for a different course, air law remained his concern, as witnessed by his study of the Paris Convention on the Regulation of Aerial Navigation and by the substantial article on parachutes which he published in 1935 in French.4 Beginning with the academic year, 1933-34, the course given by Professor Vladimir Mandl on industrial law appears in the university curriculum, as it did in the year 1938-39. As is known, German troops occupied the whole of Czechoslovakia in March 1939, and in autumn of that year the Nazis closed all Czech universities. That also meant the end of Mandl's University teaching. During the last few years before the occupation Professor Mandl participated in the search of docu- ments and objects for the aeronautical collection of the National Technical Museum in Prague.5 For this purpose he visited the foremost foreign mu- seums and reported on them in Czech journals. For example, in 1937 he visited the Frunze Air Museum in Moscow and in summer 1938 the avia- tion collection of the Smithsonian Institution in Washington.8 He was also familiar with the aero- nautical collections in Paris and Munich. The loss of independence in 1939 interrupted the successful development of Czechoslovak avia- tion. Shortly before those events, Mandl concluded his article about the Smithsonian's Museum by saying: "The glorious past and the promising pres- ent of Czechoslovak aviation will certainly be re- flected in one of the best collections of the Czecho- slovak Technical Museum." Mandl thought about the Museum also during his "involuntary holidays in the sanatorium in Pies" when his illness was added to the tragedy of his nation.7 His keen interest in aeronautics led Vladimir Mandl to think about the more advanced means of space transport. While the pioneers of astronautics tested their modest rockets, Mandl thought of them as instruments of navigation in space which would some day require new rules of law—space law. It was in this new field that he was able to apply crea- tively his broad knowledge, which went well beyond the usual limits of legal scholarship and which made it possible for him to contribute to the tech- nical aspects of rocketry as well. The results of his studies and thoughts in astronautics fall into two categories. The first is found in his book, "The Problem of Interplanetary Transport," which appeared in 1932 in Prague.8 His treatise opened with a brief survey of developments in astronautics, in which he de- scribed the work of Konstantin Tsiolkovskiy, Dr. Robert H. Goddard, Dr. Franz von Hoefft, Pro- fessor Hermann Oberth, and others. In the second part he explained the basic principles of rocketry. The book concluded by his own drawing of a high altitude rocket (Figure 2) for which he applied, on 14 April 1932, for a Czechoslovak patent.9 Mandl's rocket would have consisted of three cylinders, one inserted into the other. The payload would have been placed in the head of the interior rocket ("automatic instruments for measurements of pres- sure, compositions of atmosphere, temperature, radiation, etc. in the stratosphere and beyond"). Nozzles in the form of ring slots around the circum- ference of the rocket would be near the top of rockets which should be fired successively. Both solid and liquid propellants would have been used. In the second category, however, without any doubt falls the important work by which the name of Professor Vladimir Mandl is recorded forever in the history of astronautics. It is continued in his monograph on "The Law of Outer Space, a Prob- lem of Spaceflight," for which he finally found a publisher in 1932 in Germany.10 In this concise book Mandl placed before the reader many NUMBER 10 89 PATENTNl OftAD REPUBLIKY fi(W\ CESKOSLOVENSKfc PfOoha k patratoveau apian lb. wtM. INiN * PATENTOVY SPIS 6.52236. Chiintoo od 15. kvMna MU. Vya**» aaaaatajki PHhliaeno M. dubna 1032. Pfedmetem vynilezu jeat vyioko itoupajid raketa, aMeni ■ aekollka vilcovitycb raket do aebc zaaunutych, poatupne vypalovanych, pH (em! po vypileni jedne rakety jcji prixdny ob»l jeet admritcn vybucbem rakety dittl, clmi dociluje ae vyhudnijilho pohoou. Zuunutlm vtlcovych raket atejne podoby da zebe st umoiAuje ipojcnl llbovolneho poMu raket, bn ujmy aerodynamickych vlutnoati ■ rovnovahy celku. Rovnovtka in pod- porovana tim, ae vyfuk vybuanych plynu dtje ae vpfedu kaade jednotlive rakety. Vhodny pohon docllen apojenim tfaakavln dvojiho druhu, toUt pevnych a kapalnych. Na vykrtau jcat maiornte achematlcky pHklad provcdcnl vynaknu. PHatroj jest seataven at tf I vakovttych raket I—III, vnunitych do acbc (vntjal raketa i. I vymaiena jcat ailnijUml Carami, oatatni rakety jaou postupn* menei a menai, avtak zafizeni jejlch jeat podoboe). Utlte6ni vaha A (samcrfinne pfiatrojc k mircni tlaku a aloienl viduchu, teploty, atrenl atd. ve vyai atratc«Kricki a i dalai) umlaUna jeat v blavt vnltfnl rakety i. III. Vybu&nc plyny naboje rakety vyfukuji tryakou B ve tvaru pratenco- ve itfrbiny kol ecleho obvodu rakety; tryace predchaai rovnei pratenoova apalovaci komora C. Tryaka je umiatina bliie vrcholu rakety, 61ml mi bytl cioaaieno rovnovahy lctu, ncbof pusobiite reakCniho u£lnku Jeat poaunuto do vyae. pfed tfiiste rakety, takie naatavi ade til vyalednice ail, jakoby raketa byla reakci taiena. nikoli tlacena jako u raket jtnycb; vedle toho mi katda raketa sm^rovc tyiky F. SUrbina tryaky, jdouc kolem celebo obvodu rakety, jeat zna(n# dlouha, fimi docUuje ae rycbMbo, udinoeho vy- praadolni traakavinove nidrte: pfi dalaicb raketich jeat dtlka tryaky vidy menii • menal. Vnltrnl rakety maji tea menil aaaobu traakavin a neaou menai niklad (tci odporu viduchu ubyvi do vyae). Pocinaje c. I. zapaluji ae rakety jedna po drub*. Kaidi raketa mi dvcji trafkavinovy naboj: pt-vny D (atfelny pracb) a tekuty B (ikapalnrni plyny nobo horlare tekutiny, alkoholy atd.). Nejprve vybuchne ciboj prschu, ktery jest nacpan v tryace a apalovaci komore. a vyiene raketu do vyae. Plameny vybuchujiclho prachu, ariicl z tryaky, ohrlvajl Uleao ra- kety a kapaliny E. ktere tamte ae nalezajl, roiUbuji ae teplem, a proudi FIGURE 2.—First page of Dr. Mandl's patent and the design of his high-altitude rocket. thoughts which have not lost their relevance despite the passage of time. Attention should first be drawn to his concept of the law of outer space as an independent legal branch, based on specific instruments of space flight and governed by different principles than is the law of the sea or the law of the air. Although the writer did not underestimate the examples of the other legal branches for analogies in special cases, he stressed the need for specific regulation of the legal problems of astronautics. From this point of view he considered in the first part of his mono- graph selected problems of civil law, criminal law, and international law concerning outer space. Still more interesting is the second part of the study, "The Future." It was not science-fiction, but a number of serious predictions which have become reality in our age. For example, Mandl opposed the then usual idea of sovereignty as applied to space without limits and asserted that sovereignty of States governs only the adjacent atmospheric space. Beyond the "territorial spaces" a vast area begins which is "independent on any terrestrial State power and is coelum liberum." 1X It is worth recalling, in this connection, that thirty years later the United Nations General As- sembly recommended in its resolution 1721/XVI of 20 December 1961 such a principle as a starting point of any space legislation, saying: "Outer space and celestial bodies are free for exploration and use by all States in conformity with international law and are not subject to national appropriation." Furthermore, this principle has been developed and inserted in Articles I—III of the Space Treaty of 27 January 1967. The concluding part of Mandl's analysis is pre- ceded by his prediction of a surprising new progress in physics, chemistry, and engineering that would correspond to a similar epoch of the 19 th century— in fact, a vision of the scientific and technical revo- 90 SMITHSONIAN ANNALS OF FLIGHT lution of our times. Moreover, as a consequence of the penetration by men into outer space, Mandl predicted a substantial change in relations between the State and its nationals which would not be based on State domination, so that both State and its nationals would become equal subjects. Accord- ing to Mandl, territory would lose its importance as one of the basic dimensions of each State, and new communities based exclusively on personal adherence would emerge. People would retain such new nationality when going to outer space and other planets. Finally, according to Mandl's conclusion, space law would become a new set of norms which will be "quite a different phenomenon than is the present law of jurists." 12 Vladimir Mandl died on 8 January 1941 at the age of 41 and was buried on 13 January 1941 at the Central Cemetery in Pilsen. Professor Mandl, who is recognized by the com- munity of space lawyers as the founding writer in this new branch of law embodied some of the characteristic features of the people from a small country in the heart of Europe, Czechoslovakia. Its best creative men, whether scientists, philosophers, or artists, always blended into their ideas the par- ticular interests of their own nation in progress and freedom with the dreams and concerns of the whole of mankind. NOTES 1. Mandl, Letecke prdvo [Air Law] (Pilsen, 1928). 2. In a report of the Accreditation Commission on Dr. Vladimir Mandl, dated 6 February 1930, the "significant juridical erudition of the author, great knowledge of liter- ature, unusual diligence and devotion to scientific work" was stressed. In his accreditation colloquium, Dr. Mandl received the unanimous approval of the seven examiners, on 20 April 1930. On 30 April 1930 he delivered a test lecture before the Board of Professors on "Liability of Contractors for Damage"; and at a meeting of the Board, when a vote in regard to his appointment was taken among the 24 voting members, 23 votes were cast for and only 1 against Dr. Mandl. 3. Decree of the Minister of Edueation 89212/3l-IV/3, of 30 September 1932. 4. Mandl, "Mezinarodni limluva o uprav£ lectectvf ze dne 13.fijna 1919" (Praha, 1932); "Le Parachute," La revue generate de droit aerien, nos. 2, 3, 4, 1935 (reprint, Paris: Les Editions Internationales, 1935). 5. In a letter dated on 28 February 1939 and addressed to one of the main organizers of that collection, Ing. Karmazin, Mandl wrote with characteristic modesty: "I have followed the history of aviation since its beginning during my child- hood, of course, only as an amateur, not a scientist. It will be a great pleasure for me to discuss with you on this sub- ject of our common concern." In a series of letters Mandl offered original suggestions concerning the organization of the collection. 6. "Aero-muzej im. M.V.Frunze v Moskve," Letectvi [Avi- ation], Praha, August 1937, p. 365; and "Aircraft Building ve Washingtone, U.S.A.," Letec [Aviator], October-November 1938, p. 165. 7. "Let us hope to see as soon as possible the accom- plishment of your life work—the Air Museum," wrote Dr. Mandl in a brief, handwritten letter to Ing. Karmazin dated 22 September 1940, only a few months before his death. 8. "Problem Mezihvezdne Dopravy" (Prague, 1932), 100 pp. 9. High Altitude Rocket, Patent 52236, Class 46d, granted on 25 September 1933. The patent provided protection from 15 May 1935. Mandl also described his rocket in his book published in Germany: Die Rakete zur Hohenforschung, Ein Beitrag zum Raumfahrt problem (Leipzig and Berlin: Hachmeister & Thai, 1934), 16 pp. 10. Das Weltraum-Recht: Ein Problem der Raumfahrt (Mannheim, Berlin, Leipzig: J. Bensheimer, 1932), 48 pp. 11. Ibid., p. 33. 12. Ibid., p. 48. In the 1930s Mandl was also interested in some more general problems of economics, science and philosophy. He explained his economic views in the follow- ing studies: Technokracie, hospoddfsky system budoucnosti? [Technocracy—Economic System of the Future?] (Prague, 1934); Pfirodovedni ndrodohospoddfskd teorie [Scientific Eco- nomic Theory] (Prague, 1936); Stat a vedeckd organizace prdce [State and Scientific Management] (Pilsen, 1937). From among his other writings the following studies should be mentioned: "Vedecka metoda Einsteinova relativismu" [Scientific Method of Einstein's Relativisme] in Ceskd mysl, caspois filosoficky [Czech Thought, a Philosophical Journal] (Prague, 1935), vol. 31, no. 3-4; Pficinnd teorie prdvni [Causal Theory of Law] (Prague, 1938); and Vdlka « mir [War and Peace] (Prague, 1938). 10. 10 Developments in Rocket Engineering Achieved by the Gas Dynamics Laboratory in Leningrad I. I. KULAGIN, Soviet Unioi The first rocket research and development body in the Soviet Union began its activities in Moscow in March 1921. Its foundation was proposed by Nikolay Ivano- vich Tikhomirov (1860-1930), a chemical engineer, the aim being to develop his invention in the field of self-propelled (rocket) mortars. This organization was originally named the Laboratory for Develop- ment of Engineer Tikhomirov's Invention. N.I. Tikhomirov's assistant and test superviser was Vladimir Andreyevich Artem'yev (1885-1962), who was appointed to the Laboratory in May 1921. The key problem encountered by the organizers of the Laboratory in the development of rocket mortars was the problem of propellant powder. The joint effort of the Laboratory and specialists from the Artillery Academy resulted in the develop- ment of granular smokeless powder with a thick web (slow-burning), based on a non-volatile trotyl- pyroxiline solvent. Along with research in powders, the structural design of missiles was developed and improved, thus modifying the original version of N.I. Tikhom- irov's rocket mortar. For example, ground-firing of powder rockets was begun in 1924 near Leningrad. In 1928, after successful development of engines burning smokeless powder, significant advances were made by powder rockets. However, a great deal of experimental work on powders had to be done in Leningrad proper. This caused unnecessary inconveniences and difficulties. Consequently in 1927, the entire Laboratory was transferred to Leningrad, where it acquired its final name, the Gas Dynamics Laboratory (GDL). During 1928 and 1933, various caliber rockets burning granular smokeless powder were developed at the GDL, and underwent official tests. These rockets were intended for firing from ground and aircraft. They were used during combat operations on the Khalkhin-Gol River and, in a somewhat modified form known as the "Katyusha," they were extensively employed in the Great Patriotic War of 1941-45. The principal authors of all these developments were staff members of the GDL: N.I. Tikhomirov, V.A. Artem'yev, B.S. Petropavlovskiy, G.E. Lange- mak, and I.T. Kleymenov. In 1927, the GDL began to develop rocket- assisted takeoff for aircraft, the aim being to shorten the takeoff. Successfully completed during and after 1932-1933 were tests of rocket-assisted takeoff units for light and heavy aircraft (types 1-4, TB-1, TB-3, and others). Beginning with 1929, the GDL broadened its work program. In April 1929, organizational work was begun to establish a GDL subdivision (later becoming Department II of GDL) for developing electrical and liquid-propellant rocket engines. Ex- perimental work in this area started on 15 May 1929. Department II of the GDL was the first state- sponsored body in the USSR charged with practical implementation of the ideas conceived by K.E. Tsiolkovskiy, the founder of contemporary cos- monautics and rocket engineering. Before Department II of the GDL inaugurated its activities, there were in the Soviet Union public bodies that engaged in investigation and populari- zation of the problems of rocket engineering and interplanetary travel. Thus, in May 1924 the Inter- planetary Travel Study Group at the Military- Research Society at the N.E. Zhukovskiy Air Force 91 92 SMITHSONIAN ANNALS OF FLIGHT Academy in Moscow was reorganized into the Society for the Study of Interplanetary Communi- cation, with G.M. Kramorov acting as chairman. Participating in the work of the newly organized society were K.E. Tsiolkovskiy, F.A. Tsander, V.P. Vetchinkin, and others. Among the personnel of the Department II of GDL who took part in development of electrical and liquid-propellant rocket engines were such talented engineers and technicians as A.L. Malyy, V.I. Serov, Ye.N. Kuz'min, Ye.S. Petrov, N.G. Chernyshev, P.I. Minayev, B.A. Kutkin, V.P. Yukov, V.A. Timofeyev, N.M. Mukhin, I.M. Pankin, and others. The work of Department II was put on a scien- tific basis from the very beginning: first, a theoreti- cal study was made of the problem, and then the theoretical principles were checked by experiment. To accomplish the principal task of developing electrical and liquid-propellant rocket engines, a number of engineering problems had to be solved in Department II of the GDL, among which were the following: 1. Working out a functional diagram of the elec- trical rocket engine; 2. selection of the working fluid (from among solid and liquid conductors) for the electrical rocket engine; 3. development of feeding devices to supply the working fluid to the thrust chamber of the elec- trical rocket engine; 4. selection of the method for feeding propellant into the thrust chamber of the liquid-propel- lant engine; 5. development of the most expedient forms for mixing chambers and for injectors; 6. solution of the problem of pump-feeding pro- pellant components; 7. investigation of the behavior of prepared pro- pellant mixtures during combustion in an open vessel and in a semienclosed volume (detonation in rocket engine); 8. development of methods for igniting propel- lant mixtures (pyrotechnical, electrical, and chemical ignition); 9. development of methods for cooling the thrust chamber and selection of heat-insulating mate- rial for the chamber; 10. selection and investigation of various types of liquid propellants and special additives, with the aim of increasing the specific weight of fuel and enhancing its calorific value, including (a) use of colloidal propellant for rocket engines and (b) production of nitrogen tetrox- ide; 11. investigation of the influence that the design elements of the engine nozzle and combustion chamber exert upon the value of the reaction force, and development of the exponential- contour nozzle; 12. design of vehicles powered by liquid-propellant motors with nominal ceiling of up to 100 km (RLA-1, RLA-2, RLA-3, and RLA-100);x 13. development of means for measuring pressure in the combustion chamber, the thrust of the rocket engine, propellant consumption, and other parameters. In 1929 and 1930, Department II first proved theoretically and experimentally the general ability of an electrical rocket engine to function, using as a working fluid liquid or solid conductors (continu- ously fed metal wires or liquid jets), exploded at a predetermined frequency by high-power electric sparks in a thrust chamber. The injector and the chamber body, separated by an insulator, were con- nected to wires running from an electric pulse generator facility of high power, whose principal elements were a high-voltage transformer, four recti- fiers, and 4-mfd oil-filled capacitors charged to 40 kv. Subjected to firing were carbon filaments, wires of aluminium, nickel, tungsten, lead and other metals, as well as such liquids as mercury and elec- trolytes. l***-^. io'r M ethyl-anii ine 80 100 80 20 l>0 60 Aniline FIGURE 9.—Ignition delays of the hypergolic fuel "Gola," showing mean scatter of ten individual values. furyl alcohol, called "Fantol" (Egelhaaf). They have particularly good hypergolity, especially with mixed acid, even when diluted to a high degree with xylol (up to 70 percent). Hydrazine also reacts hypergolically with nitric acid. Almost all proposed hypergolous propellants con- sisted of mixtures of different compounds. This re- sults, of course, in a complication of the individual effects, yet mixing offers the possibility of intensify- ing one or the other of the desired properties, for instance, the chemical affinity of a mixture of two substances is in some way analagous to the solidifi- cation diagram of a system. Figure 10 shows this affinity expressed as a limit concentration, i.e., the acid concentration at which ignition takes place without perceptible delay. It can easily be under- stood that mixtures may have a considerably higher affinity than the single components, an effect which has also been proved true with numerous other sub- stances. The same diagram shows the lowest admis- sible temperature, the so-called "cold point." This cold point is given at both ends of the diagram by the solidification point, in the middle by the high- est admissible viscosity, which was assumed to be 40 centi-strokes for a particular case. In this special case the optimum in regard to cold point as well as that to ignition delay are almost identical. There are, however, combinations of substances showing 0 20 iO 60 80 % 100 Aniline 100 % 80 60 iO 20 0 Cydo-hexylamine FIGURE 10.—Characteristic values of the hypergolic fuel sys- tem with aniline and cyclo-hexylamine, showing limit con- centration (i.e., acid concentration up to which no delay is noticed. NUMBER 10 109 the contrary; we then have to try to bring both optima into accordance by adding further com- ponents. Figure 11 shows different diagrams obtained in the development of "visol" fuels. We are dealing here with a mixture of four components: two differ- ent visoles, the vinyl-butyl-ether (visole 1) and the butane-diol-divinyl-ether (visole 4), and two differ- ent organic amino compounds, aniline and methyl- aniline. The ignition delay is shown as a function of the composition of the amino mixture. The dotted lines correspond to the substances with 10 parts by volume; the broken lines, to the substances with 15 parts by volume; and the solid lines, to the sub- stance with 20 parts by volume of amino mixture. Finally, the four diagrams differ in their visole com- position. Without going into more detail, as for instance the conversion of a minimum into a maxi- mum by changing the composition of the visole part, I want to draw attention to the extraordinary 20 -2 ser 15 -r* f % '0 \ \ \ \ \ \ \ \ \> x// If jT^ Y \ Vfc -dL Visol 1A Vxnl LA 75 25 \ \ \ \ » t i \ ' 1 ^ f f \V w \ ^^ Visol 1A Vhtnl LA 69 31 .c: I »| 55 1/ ^ U— Visol 1A _ 58 Visol LA L2 1MR -2 20 sec 15 It? 10 \ * > 1 \ ^-- \ \ ^V Vis ol 1A eo Vis oUA 37 50—- 1MR 50 1R J ! 50 50 LO °C L5 50 55 FIGURE 11.—Influence of the composition of the visol and amine composition in visol fuels (proportionality factors parts by weight). 110 SMITHSONIAN ANNALS OF FLIGHT 1 Reaction chamber. 2 Thermostate tor low temperature, device for cooling the pot. 3 CO2 solid t> Sliding plug 5 Distributer plate. 6 Starter 7 Photocell 6 Amplifier 9 Recorder Mill N2 or C02 differences caused by small changes in the absolute contents of the amino components. This sensitivity made studies very difficult from the point of view of affinity; the systems shows all properties of multi- component systems and the technician is tempted to speak of a eutectic. It should also be mentioned that the ignition delays given are not claimed to be absolute values. Ignition delay is more or less influenced by the way in which the components are brought together. We might even arrive at a point where an arrangement which is favorable for one combination of sub- stances results in long ignition delays for another fuel system. The ignition delay times were measured by a photoelectric cell by feeding the oxidizer uni- formly and reducibly into the fuel, which was kept in a crucible (Figure 12). Figure 13 shows a varia- tion of an apparatus we developed for the measure- ment of ignition delay at low temperatures. FIGURE 12.—Device for measuring ignition delay. Some remarks should be made on the ignition of hypergoles and the relation to the design of mixing FIGURE 13.—Ignition-delay apparatus for low temperature. injectors. We found that generally the hypergoles cannot be ignited in every case by quick and inti- mate mixing in the stoichiometric ratio. We postu- lated a stoichiometric ignition ratio, that means the ratio of the primary reactions which are taking place at the boundary surface as the most important first step for immediate ignition of hypergolic sys- tems. But we could not complete our studies in this interesting field of theory and practice. From the development of suitable mixing injectors we learned that the energy used for atomizing has to be kept low. We used mixing arrangements which brought together both flows with a small amount of energy, but with split-up boundary surfaces, and they proved to be good. This work, started in the thirties, was continued until the end of World War II, during which time about 1100 different combinations of hypergoles were investigated, leading us to a broad view of possible propellant systems. To complete this review of research done in the beginnings of rocketry, I should like to report on our efforts to discover new materials and cooling systems for the rocket nozzle, which was exposed to a high thermal load uncommon at that time. These investigations were concentrated on "sweating" or "transpiration" cooling systems, today widely known and applied to turbine blades. It can be assumed that similar principles for the cooling of NUMBER 10 111 WOO °c 800 600 COO 200 rocket combustion chambers have been developed elsewhere, but I should like to mention at this point my former colleague Meyer-Hartwig who devoted intensive studies to these topics. There are three significant effects which reduce the surface temperature: heat absorption by passing the cooling liquid through the porous wall, heat absorption by the evaporation of the cooling liquid, and the additional boundary layer consisting of the mass addition of cooling liquid at the surface of the wall. A temperature profile for the cooling of a solid and a porous wall is represented in Figure 14. At a gas temperature of 1100°C and a velocity of 600- 700 m/s the surface temperature can be reduced to 100°C applying 0.04 g/(s-cm2) specific mass flow rate (Figure 15). Figure 16 shows the application of porous mate- rial in a rocket nozzle. At a chamber pressure of 36 kp/cm2 and a gas temperature of about 2500 °K, 0.6 g/(scm2) of cooling liquid were fed through the nozzle wall, which amounts to less than 2 percent of the main mass flow rate of the combustion chamber. The porous materials used for the research in sweat- cooling were made from powdered steel and copper. The strength-to-weight ratio of this material was almost equal to that of the compact material. \ \ \ 1 \ I N s> -" - — 02 g/cm2sec 01 k FIGURE 15.—Surface temperature as a function of specific coolant flow rate. .Cooling Boundary-layer Additional Boundary-layer Solid Wall Porous Wall FIGURE 14.—Temperature profiles for solid and porous walls. Figure 17 shows different test bars, orifices, and rocket nozzles developed in our laboratories. The development of porous materials for sweat-cooling was started with nonmetallic ceramics, but in con- nection with steel constructions a lot of difficulties arose due to differing rates of thermal expansion. Sweating-nozzle Two -part tiller Pressure-gas Jacket 1 Cooling-distributer Cooling -agent FIGURE 16.—Sweat-cooled material nozzle. 112 SMITHSONIAN ANNALS OF FLIGHT £!» a I I I * ^l^^r FIGURE 17.—Development of sweat-cooled materials. Thus, we switched over to metallic materials. Tak- ing advantage of the excellent properties of cer- amics we tried to weld metal and ceramics. Zones of mixtures of ceramic and of increasing amount of metal were sintered to the ceramic (Figure 18). By this process advantage could be taken of the differ- ent properties of metal and ceramic. Today the mixtures of metal and ceramics are known as "cermets." NOTES 1. "Some Special Problems of Power Plants," of which this paper is a revised and expanded version, was presented at the AGARD First Guided Missiles Seminar, Munich, Germany, 6r\ ^Ceramics \ \ \ Mixture (cermets) 'Metal FIGURE 18.—Test rod and nozzle of compound material. April 1956, and appeared under the author's name in the History of German Guided Missiles Development (pp. 238- 252), edited by Th. Benecke and A. W. Quick and published for and on behalf of The Advisory Group for Aeronautical Research and Development, North Atlantic Treaty Orga- nization (AGARD) by the Wissenschaftliche Gesellschaft fur Luftfahrt E. V. (Brunswick, Germany: Verlag E. Appelhans & Co., 1957). From this source are taken Figures 1-4, 6-11, 15, and 18 in this paper.—Ed. 12 On the GALCIT Rocket Research Project, 1936-38 FRANK J. MALINA, United States Introduction The following recollections are based on memory, on unpublished documents, and on published mate- rial available to me. I present them fully recogniz- ing the fallibility of memory, and the unavoidable injection of personal evaluations and judgments. Although in our youthful enthusiasm we were already convinced, in 1936, that rocket research for space exploration was important, we made no sys- tematic effort to preserve our papers and photo- graphic records. My interest in space exploration was first aroused when I read Jules Verne's De la terre a la lune in the Czech language as a boy of 12 in Czechoslovakia, where my family lived from 1920 to 1925. On our return to Texas, I followed reports on rocket work as they appeared from time to time in popular magazines. In 1933 I wrote the following paragraph for a technical English Course at Texas A.&M. Col- lege: Can man do what he can imagine? - Now that man has con- quered travel through the air his imagination has turned to interplanetary travel. Many prominent scientists of today say that travel through space to the Moon or to Mars is impossible. Others say, "What man can imagine, he can do." Many difficulties present themselves to interplanetary travel. The great distance separating the heavenly bodies would require machines of tremendous speeds, if the distances are to be traversed during the lifetime of one man. Upon arrival at one of these planets the traveler would require breathing apparatus, for the astronomers do not believe the atmosphere on these planets will support human life as our atmosphere does. If a machine left the earth, its return would be practically impossible, and those on the earth would never know if the machine reached its destination. In 1934 I received a scholarship to study mechan- ical engineering at the California Institute of Tech- nology. Before the end of my first year there I began part-time work as a member of the crew of the GALCIT (Guggenheim Aeronautical Laboratory, California Institute of Technology) ten-foot wind tunnel. This led to my appointment in 1935 as a graduate assistant in GALCIT. The Guggenheim Laboratory, at this time, a few years after its founding, was recognized as one of the world's centers of aeronautical instruction and research. Under the leadership of Theodore von Karman (1881-1963), GALCIT specialized in aero- dynamics, fluid mechanics, and structures. 1-a Von Karman's senior staff included Clark B. Millikan (1903-1966), Ernest E. Sechler, and Arthur L. Klein. The laboratory was already carrying out studies on the problems of high-speed flight, and the limits of the engine-propeller propulsion system for air- craft were beginning to be clearly recognized. In 1935-36 William W. Jenney and I conducted experiments with model propellers in the wind tunnel for our master's theses. My mind turned more and more to the possibilities of rocket propul- sion while we analyzed the characteristics of pro- pellers. In March 1935, at one of the weekly GALCIT seminars, William Bollay, then a graduate assistant to von Karman, reviewed the possibilities of a rocket-powered aircraft based upon a paper pub- lished in December 1934 by Eugen Sanger (1905- 1964), who was then working in Vienna.4 Bollay carried out independent design and performance studies of rocket-powered aircraft and presented them on 27 March 1935 at a Caltech seminar on rockets. Local newspapers reported on Bollay's lecture,5 which resulted in attracting to GALCIT two rocket enthusiasts—John W. Parsons (1914-1952) and Edward S. Forman. Parsons was a self-trained chem- 113 114 SMITHSONIAN ANNALS OF FLIGHT ist who, although he lacked the discipline of a formal higher education, had an uninhibited and fruitful imagination. He loved poetry and the exotic aspects of life. Forman, a skilled mechanic, had been working with Parsons for some time on powder rockets. They wished to build a liquid- propellant rocket motor, but found that they lacked adequate technical and financial resources for the task. They hoped to find help at Caltech. They were sent to me, and then began the series of events that lead to the establishment of the Jet Propulsion Laboratory.6 On the following 4th of October, Bollay gave a lecture before the Institute of the Aeronautical Sciences in Los Angeles. He concluded by saying: The present calculations show that we can achieve (by means of rocket planes) higher velocities and reach greater heights than by any other method known so far. The high velocities should prove an attraction to the sportsman, to the military authorities, and perhaps to a few commercial enterprises. The high ceiling is of great interest to the meteorologist and the physicist. There are thus potent reasons for the further development of the rocket plane. I hope I have shown by these calculations that the idea of the rocket plane is not so fantastic as it at first appears and that at present it appears just at the border of the practically attain- able and is certainly worthwhile working for. On the other hand, it seems improbable that the rocket plane will be a very hopeful contender with the airplane in ordinary air passenger transportation. For this purpose the stratosphere plane seems eminently more suitable. Formation of the GALCIT Rocket Research Project After discussion with Bollay, Parsons, and For- man, I prepared in February 1936, a program of work whose objective was the design of a high-alti- tude sounding rocket propelled by either a solid- or liquid-propellant rocket engine. We reviewed the literature published by the first generation of space-flight pioneers—Tsiolkovskiy (1857-1935), Goddard (1882-1945), Esnault-Pelterie (1881-1957) and Oberth.7 In scientific circles, this literature was generally regarded more in the na- ture of science fiction, primarily because the gap between the experimental demonstration of rocket- engine capabilities and the actual requirements of rocket propulsion for space flight was so fantas- tically great. This negative attitude extended to rocket propulsion itself, in spite of the fact that Goddard realistically faced the situation by decid- ing to apply this type of propulsion to a vehicle for carrying instruments to altitudes in excess of those that can be reached by balloons, an application call- ing for an engine of much more modest perform- ance. We were especially impressed by Sanger's report of having achieved an exhaust velocity of 10,000 feet per second (specific impulse of 310) with light fuel oil and gaseous oxygen.8 Unfortunately, we were never able to understand the method Sanger used for presenting his experimental results. We concluded from our review of the existing information on rocket-engine design, including the results of the experiments of the American Rocket Society, that it was not possible to design an engine to meet specified performance requirements for a sounding rocket which would surpass the altitudes attainable with balloons. It appeared evident to us, after much argument, that until one could design a workable engine with a reasonable specific impulse there was no point in devoting effort to the design of the rocket shell, propellant supply, stabilizer, launching method, payload parachute, etc. We, therefore, set as our initial program the fol- lowing: (1) theoretical studies of the thermody- namical problems of the reaction principle and of the flight performance requirements of a sounding rocket, and (2) elementary experiments to deter- mine the problems to be met in making accurate static tests of liquid- and solid-propellant rocket engines. This approach was in the spirit of von Karman's teaching. He always stressed the impor- tance of getting as clear as possible an understand- ing of the fundamental physical principles of a problem before initiating experiments in a purely empirical manner, for these can be very expensive in both time and money. Parsons and Forman were not too pleased with an austere program that did not include the launch- ing, at least, of model rockets. They could not resist the temptation of firing some models with black powder motors during the next three years. Their attitude is symptomatic of the anxiety of pioneers of new technological developments. In order to obtain support for their dreams, they are under pressure to demonstrate them before they can be technically accomplished. Thus one finds during this period attempts to make rocket flights, which, doomed to be disappointing, made support even more difficult to obtain. NUMBER 10 115 The undertaking we had set for ourselves re- quired, at a minimum, informal permission from Caltech and from the Guggenheim Laboratory be- fore we could begin. In March, I proposed to Clark B. Millikan that I continue my studies leading to a doctorate and that my thesis be devoted to studies of the problems of rocket propulsion and of sound- ing-rocket , flight performance. He was, however, dubious about the future of rocket propulsion, and suggested I should, instead, take one of many engi- neering positions available in the aircraft industry at that time. His advice was, no doubt, also in- fluenced by the fact that GALCIT was then carry- ing out no research on aircraft power plants. I would like to add that later he actively supported our work. I knew that my hopes rested finally with von Karman, the director of GALCIT. Only much later did I learn that already in the 1920s, in Germany, he had given a sympathetic hearing to discussions of the possibilities of rocket propulsion,9 and that in 1927 he had included in his lectures in Japan a reference to the problems needing solution before space flight became possible. He was at this time studying the aerodynamics of aircraft at high speeds, and was well aware of the need for a propulsion system which would surmount the limitations of the engine-propeller combination. After considering my proposals for a few days, he agreed to them.10 He also gave permission for Par- sons and Forman to work with me, even though they were neither students nor on the staff at Cal- tech.11 This decision was typical of his unorthodox attitude within the academic world. He pointed out, however, that he could not find funds in the budget of the Laboratory for the construction of experimental apparatus. At Caltech, we were given further moral support by Robert A. Millikan (1868-1953), then head of the Institute, who was interested in the possibilities of using sounding rockets in his cosmic ray research, and by Irving P. Krick, then head of meterological research and instruction. During the next three years we received no pay for our work, and during the first year we bought equipment, some secondhand, with whatever money we could pool together. Most of our work was done on weekends or at night. We began our experiments with the construction of an uncooled rocket motor similar in design to one that had been previously tried by the American Rocket Society. For propellants we chose gaseous oxygen and methyl alcohol. Our work in spring 1936 attracted to our group two GALCIT graduate students, Apollo M. O. Smith and Hsue-shen Tsien. Smith was working on his masters degree in aeronautics; Tsien, who became one of the outstanding pupils of von Karman, was working on his doctorate. Smith and I began a theoretical analysis of flight performance of a sounding rocket, while Tsien and I began studies of the thermodynamic problems of the rocket motor. Some of the members of our group in 1936 and Dr. von Karman are shown in Figure 1. The work of our group, once it was approved by von Karman, had the benefit of advice from von Karman him- self, C. B. Millikan, and other GALCIT staff mem- bers. We realized from the start that rocket research would require the ideas of many brains in many fields of applied science. I was very fortunate at this time to enter von Karman's inner circle of associates because he needed someone to prepare illustrations for the text- book Mathematical Methods in Engineering he was writing with Maurice A. Biot. Bollay had been assisting von Karman with the manuscript of the book, and introduced me to him. When Bollay left for Harvard University in 1937, I also inherited his job as "caretaker" of the manuscript. Thereafter, I worked with von Karman on many projects until his death in 1963. In a way be became my second father. We worked so closely together during the formative years of the Jet Propulsion Laboratory, until he went to Washington in 1944, that it is not always possible to separate the contribution either of us made to technical and organizational de- velopments during the period 1939-44. It is necessary to point out, however, that during the period of the GALCIT Rocket Research Project the initiative rested with our group, and it fell to me to hold the group together. Relations between the Project and R. H. Goddard The group heard with excitement in the summer of 1936 that Robert H. Goddard would come to Caltech in August to visit R. A. Millikan,12 who was a member of a committee appointed by the Daniel and Florence Guggenheim Foundation to 116 SMITHSONIAN ANNALS OF FLIGHT FIGURE 1.—a, John W. Parsons; b, Theodore von Karman; c, Frank J. Malina; d, Hsue-shen Tsien (Chien Hsueh-sen); e, Apollo M. O. Smith. NUMBER 10 117 advise on the support given by the Foundation to Goddard for the development of a sounding rocket.13 Millikan arranged for me to have a short discussion with Goddard on 28 August, during which I told him of our hopes and research plans. I also arranged to visit him at Roswell, New Mexico, the next month, when I was going for a holiday to my parents' home in Brenham, Texas.14 I believe it was before Goddard's arrival in Pasadena that Mil- likan had already written for me a letter of intro- duction to him in connection with the possibility of my visiting his Roswell station.15 In Milton Lehman's biography of Goddard10 ap- pears a rather strange and inaccurate account of my visit to Roswell. No mention is made of the fact that R. A. Millikan had arranged for me to meet with Goddard during his visit to Caltech. Part of the account by Lehman reads: The Goddards had no sooner returned to Mescalero Ranch at the end of August than they found one of Cal. Tech's graduate students waiting to see the professor. The same day Goddard received a note from Millikan asking him to extend "all possible courtesies" to the young student, Frank J. Malina. My recollections of my visit to Roswell are that both Dr. and Mrs. Goddard received me cordially. My day with him consisted of a tour of his shop (where I was not shown any components of his sounding rocket), of a drive to his launching range to see his launching tower and 2000-pound-thrust static test stand, and of a general discussion during and after lunch. He did not wish to to give any technical details of his current work beyond that which he had published in his 1936 Smithsonian Institution report, with which I was already famil- iar. This report, of a very general nature, was of limited usefulness to serious students of the sub- ject.17 On 1 October 1936 I wrote to Goddard: 18 I have just returned to the Institute after several weeks in Texas. I wish to thank you and your wife for the hospitality shown me and you for your kindness in allowing me to inspect that part of your work which you considered per- missible under the circumstances. i I recall two special impressions he made on me. The first was a bitterness towards the press. He showed me a clipping of an editorial, which had appeared in the New York Times years earlier (13 January 1920), that ridiculed him, saying that a professor of physics should know better than to make space flight proposals, as they violated a fundamental law of dynamics. He appeared to suffer keenly from such nonsense directed at him. The second impression I obtained was that he felt that rockets were his private preserve, so that any others working on them took on the aspect of intruders. He did not appear to realize that in other countries were men who, independently of him, as so frequently happens in the history of technology, had arrived at the same basic ideas for rocket pro- pulsion. His attitude caused him to turn his back on the scientific tradition of communication of results through established scientific journals, and instead he spent much time on patents, especially after he published his classic Smithsonian Institu- tion report of 1919 on "A Method of Reaching Ex- treme Altitudes." 19 As I departed, Goddard suggested that I come to work with him at Roswell when I completed my studies at Caltech. This was intriguing to me; but by the time I completed my doctorate in 1940 we had obtained governmental support for rocket re- search, and were building an effective research establishment. A year later I wrote to Goddard in connection with an analysis of the flight performance of a sounding rocket with a constant thrust, which Smith and I were carrying out.20 To the request for flight data on his rockets, he answered on 19 October 1937, as follows: I have your letter of the fourteenth relative to data for your study of vertical rocket flight. The gyroscopically stabilized flights described in the report to which you refer were, as therein stated, for stabilization during the period of propulsion, and not thereafter, and the trajectories were accordingly not vertical throughout the flights. The data regarding heights and speeds, while suffi- ciently accurate to describe the performance in general terms, would therefore hardly be satisfactory for exact calculations made under the assumption that the flights were vertical. Further, thrusts were not measured when the rockets were used for flights, and I have reason to believe that we did not always have the high efficiencies, in flight, that we obtained in certain of the static tests. As stated in the paper, the main object was to obtain stabilization and satisfactory performance in flight, and I should prefer to have any analyses of performance made for flights in which height was the main consideration. We have had further stabilized flights since the paper was written, but the work is not yet sufficiently complete for publication. The rockets used in the flights described were all 9 inches in diameter, and the initial altitude was about 4000 feet.2i In a letter home dated 23 October, I wrote: Smith and I are working on the performance paper sporad- 118 SMITHSONIAN ANNALS OF FLIGHT ically. I wrote to Goddard for some data not long ago; an answer arrived during the week. He wrote that he did not have the data desired. We have some data on his flights we want to use in our paper, now we are in a quandary over its use. We may write the paper as originally planned and let Goddard read it before publishing it.22 On 7 June 1938,1 wrote home: Had lunch at the Atheneaum with the head of the A.P. science news service last Wednesday. He is making a trip across the country looking for the spectacular. He saw Goddard and was impressed. Judging by his writeup of what he saw, Goddard is almost at the same place he was 2 years ago. We find it difficult to understand Goddard's method of attack of the whole research. Don't think it is the result of personal jealousy on our part. It would be to our benefit if he did get something significant.23 On 26 September 1938,1 wrote: The research is bogged down; however, some interesting news was brought by Karman from New York. By the way, for some reason he thought I was going to be at the meeting in Boston. While in New York Karmdn and Clark Millikan had a conference with Guggenheim and Goddard upon the latter's invitation.2* It seems Goddard is beginning to believe that perhaps our group may be of some use to him. Karman told him that we would be glad to co-operate with him if he kept no secrets from us. Don't know what will develop. Goddard may come to Pasadena in a couple of months.2s Von Karman, in The Wind and Beyond writes: The trouble with secrecy is that one can easily go in the wrong direction and never know it. I heard, for instance, that Goddard spent three or four years developing a gyroscope for his sounding rocket. This is a waste of time, because a high- altitude rocket does not need a complex tool like a gyroscope for stabilization in flight. At the start, the rocket can be stabilized by a launching tower somewhat taller than the one Goddard actually used. After emerging from the tower, if it has been boosted to enough speed, it can be stabilized accu- rately enough with fixed fins. Malina and his Jet Propulsion Laboratory team demonstrated this in 1945 when they launched the WAC Corporal, America's first successful high- altitude rocket, to a height of 250,000 feet. I believe Goddard became bitter in his later years because he had had no real success with rockets, while Aerojet- General Corporation and other organizations were making an industry out of them. There is no direct line from Goddard to present-day rocketry. He is on a branch that died. He was an inventive man and had a good scientific foundation, but he was not a creator of science, and he took himself too seriously. If he had taken others into his confidence, I think he would have developed workable high-altitude rockets and his achievements would have been greater than they were. But not listening to, or communicating with, other qualified people hindered his accomplishments.26 With this background to the relations between Goddard and the Project, a summary of his effect on our work can be made. This appears needed, for erroneous impressions exist as to his influence on rocket research at Caltech. As I pointed out earlier, the stimulus leading to the formation of the GALCIT Rocket Research Project was Sanger's work in Vienna.27 Like God- dard, our group at first believed that the most promising practical application of rocket propul- sion would be a sounding rocket for research of the upper atmosphere, which was of interest at Cal- tech in connection with cosmic ray studies and with meteorology requirements. Actually it did not turn out this way, for the first application of rocket power we successfully made was in assisting the takeoff of aircraft. Our group studied and repeated some of God- dards' work with smokeless-powder impulse-type motors, upon which he had reported in his Smith- sonian report of 1919.28 Work on this type of solid- propellant rocket motor was, however, dropped by the group in 1939 in favor of developing one of the constant-pressure, constant-thrust type. Goddard's smokeless powder rocket engine did, however, find application in armament rockets during World War II. To the best of my recollection, we studied only a few of the patents Goddard had taken out up to that time. As is well known, patents are not equiva- lent to know-how and rarely provide the analytical basis for engineering design. His publications, to- gether with those of Tsiolkovskiy, Esnault-Pelterie, Oberth, and Sanger, provided important leads, but much work remained to be done before rocket engines became a useful reality. There is no doubt that had Goddard been willing to co-operate with our Caltech group, his many years of experience would have had a strong in- fluence on our work. As it happened, our group independently initiated the development of liquid and solid propellants different from those that Goddard studied. When finally in 1944 I initiated the construction of the WAC Corporal sounding rocket at the Jet Propulsion Laboratory, it bore little technical relation to Goddard's sounding rocket of 1936, about which we still did not have any detailed information. Research Undertaken by the Group On 31 October 1936, the first try of the portable test equipment was made for the gaseous-oxygen- NUMBER 10 119 methyl-alcohol rocket motor in the area of the Arroyo Seco back of Devil's Gate Dam, on the western edge of Pasadena, California, a stone's throw from the present-day Jet Propulsion Labora- tory. I learned several years later from Clarence N. Hickman that he and Goddard had conducted smokeless-powder armament rocket experiments at this same location during World War I. On 1 November, I wrote home as follows: This has been a very busy week. We made our first test on the rocket motor yesterday. It is almost inconceivable how much there is to be done and thought of to make as simple a test as we made. We have been thinking about it for about 6 months now, although we had to get all the equipment together in two days, not by choice, but because there are classes, and hours in the wind tunnel to be spent. Friday we drove back and forth to Los Angeles picking up pressure tanks, fittings and instruments. Saturday morning at 3:30 a.m. we felt the setup was along far enough to go home and snatch 3 hours of sleep. At 9:00 a.m. an Institute truck took our heaviest parts to the Arroyo, about 3 miles above the Rose Bowl, where we found an ideal location. Besides Parsons and me, there were two students working in the N.Y.A. work- ing for us. It was 1:00 p.m. before all our holes were dug, sand bags filled, and equipment minutely checked. By then Carlos Wood and Rockefeller had arrived with two of the box type movie cameras for recording the action of the motor. Bill Bollay and his wife also came to watch from behind the dump. Very many things happened that will teach us what to do next time. The most excitement took place on the last "shot" when the oxygen hose, for some reason, ignited and swung around on the ground, 40 feet from us. We all tore out across the country wondering if our check valves would work. Unfortunately Carlos and Rocky had to leave just before this "shot" so that we have no record on film of what happened. As a whole the test was successful.29 A number of tests were made with this transport- able experimental setup (see Figures 2 and 3); the last one on 16 January 1937 when the motor ran for 44 seconds at a chamber pressure of 75 pounds per square inch.30 /^ ""* FIGURE 2.—-Members of GALCIT rocket research group during early test (1936): from left, Rudolf Schott, Apollo M. O. Smith, Frank J. Malina, the late Edward S. Forman (died 1973), and the late John W. Parsons. 120 SMITHSONIAN ANNALS OF FLIGHT COOLING WATIR, PuoTec-rive 'BARRIER fo« OBSERVERS FIGURE 3.—Schematic diagram of test setup similar to one used by GALCIT rocket research group on 11 November 1936. Propellant was gaseous oxygen/methyl alcohol. In March 1937, Smith and I completed our analy- sis of the flight performance of a constant-thrust sounding rocket. The results were so encouraging that our Project obtained from von Karman the continued moral support of GALCIT. We were authorized to conduct small-scale rocket motor tests in the laboratory. This permitted us to reduce the time we wasted putting up and taking down the transportable equipment we had used in the Arroyo Seco. Von Karman also asked me to give a report on the results of our first year's work at the GALCIT seminar at the end of April. The unexpected result of the seminar was the offer of the first financial support for our Project. Weld Arnold (1895-1962), then an assistant in the Astrophysical Laboratory at Caltech, came to me and said that in return for his being permitted to work with our group as a photographer he would make a contribution of $1,000 for our work. His offer was accepted with alacrity, for our Project was destitute. This enabled Parsons and me to give up our effort to write an anti-war novel with a plot, of course, revolving around the work of a group of rocket engineers. We had hoped to sell it for a large sum to a Hollywood studio as a basis for a movie script to support the work of the project! This was of some relief to me, for I could then spend less time in Parson's house, where he was accumulating tetranitromethane in his kitchen. Arnold, who commuted the five miles between Glendale and Caltech by bicycle, brought the first 500 dollars for our project in one- and five-dollar bills in a bundle wrapped in newspaper! We never learned how he had accumulated them. When I placed the bundle on the desk of C. B. Millikan with the question "How do we open a fund at Cal- tech for our project?," he was flabbergasted. What has been called the original GALCIT rocket research group was now complete. It con- sisted of Parsons, Forman, Smith, Tsien, Arnold, and myself. In June 1937, studies made by the group up to that time, including Bollay's paper of 1935, were collected together into what our group called its "bible." 31 The "bible" contained the following papers: 1. "Proposed Investigations of the GALCIT Rocket Research Project; Discussions of Labora- tory for Conducting Tests, and Reports of Ex- periments Conducted during the Fall of 1936," by F. J. Malina, 10 April 1937. 2. "Analysis of the Rocket Motor," by F. J. Malina, 10 April 1937. 3. "The Effect of Angle of Divergence of Nozzle on the Thrust of a Rocket Motor; Ideal Cycle of a Rocket Motor; Ideal Rocket Efficiency and Ideal Thrust; Calculation of Chamber Tempera- ture with Dissociation," by H. S. Tsien, 29 May 1937. 4. "A Consideration of the Applicability of Vari- ous Substances as Fuels for Jet Propulsion," by J. W. Parsons, 10 June 1937. 1. NUMBER 10 121 5. "Rocket Performance" (Rocket Shell as a Body of Revolution), by F. J. Malina and A. M. O. Smith, 15 April 1937. 6. "Performance of the Rocket Plane," by W. Bollay (1935). The paper on the performance of a sounding rocket by Smith and myself became in 1938 the first paper published by the Institute of Aero- nautical Sciences (now American Institute of Aero- nautics and Astronautics) in the field of rocket flight.32 Smith and I had worked on this paper for many days and nights. On 13 December 1937, I wrote home: Smith and I were much disappointed last week when we found a French paper with a study similar to ours. >Have decided not to send our paper to France. (REP-Hirsch Prize competition). The finding does not affect the N.Y. presentation. Caltech has been rather unlucky in having other men beat them to publication. My room-mate [Martin Summer field] also has the same misfortune.33 The French paper referred to above was "Les Fusses volantes m£t£orologiques" published in October 1936 by Willy Ley and Herbert Schaefer in L'Aerophile.34 Smith's and my paper was, however, more general in discussing the influence of design parameters, and more suitable for application to particular cases of a sounding rocket propelled by a constant-thrust rocket engine. My paper on the analysis of the rocket motor, including Tsien's calculation of the effect of the angle of divergence of the exhaust nozzle on the thrust of a rocket motor, was published by the Journal of the Frank- lin Institute in 1940.35 The paper by Parsons led eventually to the development of red fuming nitric acid as a storable oxidizer, and he also anticipated the use of boron hydride as a fuel.36 Many of his suggestions were incorporated in patents which he and I prepared in 1943 and assigned to the Aerojet- General Corporation of which we were co-founders in 1942.37 When von Karman gave the group permission to make small-scale experiments of rocket motors at GALCIT, we decided to mount a motor and pro- pellant supply on a bob of a 50-foot ballistic pendulum, using the deflection of the pendulum to measure thrust. The pendulum was suspended from the third floor of the Laboratory with the bob in the basement. It was planned to make tests with various oxidizer-fuel combinations. We selected the combination of methyl alcohol and nitrogen tetroxide for our initial try. Our first mishap occurred when Smith and I were trying to get a quantity of the nitrogen tetroxide from a cylinder that we had placed on the lawn in front of Caltech's Gates Chemistry Building. The valve on the cylinder jammed, causing a fountain of the corrosive liquid to erupt from the cylinder all over the lawn. This left a brown patch there for several weeks, to the irritation of the gardener. When we finally tried an experiment with the motor on the pendulum, there was a misfire, with the result that a cloud of nitrogen tetroxide and alcohol permeated most of GALCIT, leaving be- hind a thin layer of rust on much of the permanent equipment of the Laboratory. We were told to move our apparatus outside the building at once. Thereafter we also were known at Caltech as the "Suicide Squad." We remounted the pendulum in the open from the roof of the building and obtained a limited amount of useful information. We made the first, or one of the first, experiments in America with a rocket motor using a storable liquid oxidizer. On the basis of this experience with nitrogen tetroxide, Parsons later developed red-fuming nitric acid as a storable oxidizer which is still being used today. Although rocket research unavoidably involves experimentation of a dangerous nature, to my knowledge no one has suffered a fatal injury up to the present day at JPL. Unfortunately, Parsons's familiarity with explosives led to contempt, and in 1952, when moving his Pasadena home labora- tory to Mexico, he dropped a fulminate of mercury cap which exploded and killed him. I wish to take this occasion to express my appreciation for his work, which was of great significance in the history of the development of American rocket technology, both as regards storable liquid propellants and composite solid propellants.38 During this period Tsien and I continued our theoretical studies of the thermodynamic charac- teristics of a rocket motor. To check our results, steps were taken to design and construct a test stand for a small rocket motor burning gaseous oxygen and ethylene gas. Von Karman reviewed our plans and agreed that we could build the apparatus, shown in Figures 4 and 5, on a platform on the eastern side of GALCIT. In 1939 this apparatus exploded. I escaped serious injury only because 122 SMITHSONIAN ANNALS OF FLIGHT BATTERY ^ Cfe FLOWMETER /i> THRUST V INDICATOR C2H4FLO*MME.TER (SEE CL FLOWMETER) HHHH—i MOTOR PRESSURE DROP IN TANKS 2AND 3 COMPRESSED \ A.R V LINE PRESSURt CVUNOER PRESSURE al i—Uo 0j> (RO*»M) CONTROL VALVES TRANSPORMCR HO AC C^—^l CONTKOU VALVES (P) (F.NE) (P) *0 I j LINE. PRESSURE FIGURE 4.—Schematic diagram of GALCIT rocket motor test stand at California Institute of Technology. von Karman had called me to bring a typewriter to his home. Parsons and Forman were shaken up but unhurt. Smith made simple experiments to determine the material from which we should make the exhaust nozzle of the motor. He describes these experiments as follows in a recent letter to me: Sometime, perhaps in the 1937-1938 school year, perhaps before [it was in the spring of 1938], we began investigation of materials—ceramics, metals, carborundum, etc. I developed a standard simple test. I would use the largest tip (No. 10, I believe) on an oxy-acetylene torch and play it over a specimen for one minute. Some super refractories spalled and popped like a pan of popcorn and some just melted. You obtained a y2" cube of molybdenum and I tested that. It did not melt, but when I removed the neutral protecting atmosphere of the torch, before my very eyes I watched it literally go up in smoke. While cooling, it dwindled from about a y2" cube to a 14" cube giving off a dense white smoke. As part of this phase you and I visited the Vitrefax Corporation in Hunting- ton Park to get help from them about super refractories. One important refractory was forcefully brought to our attention. We watched them make mullite and saw large graphite electrodes working unscathed in large pots of boiling super NUMBER 10 123 FIGURE 5.—Overall view of GALCIT test stand at Caltech (top), details of control panel (center), and ethylene tanks mounted in balance structure (bottom). From Popular Mechanics (August 1940). 124 SMITHSONIAN ANNALS OF FLIGHT refractory. This opened our eyes to the possibilities of graph- ite. It tested well under the torch. Later, shortly before I left Caltech in June 1938, I happened to try the torch on a 1/2" x 2" x 12" long piece of copper bar stock. The torch could not hurt this piece at all and this test opened our eyes to the possibilities of massive copper for resisting heat.39 The first combustion chamber liner and exhaust nozzle of the motor were made of electrode graphite. Later the exhaust nozzle was made of copper. An experiment made in May 1938, at a chamber pres- sure of 300 pounds per square inch for a period of one minute, showed that the graphite had with- stood the temperature and that the exhaust nozzle throat, which was 0.138 inch in diameter, suffered only an enlargement of 0.015 inch.40 The motor delivered a thrust of the order of 5 pounds. In March 1938, A. Bartocci in Italy published the results of his extensive experiments with a rocket motor of dimensions similar to ours with cold oxygen gas.41 His results were in close agree- ment with the theoretical analysis which Tsien and I had made. A report of the first series of experiments with our apparatus is contained in my doctorate thesis of 1940.42 In the winter of 1938, Tsien and I also extended the study, by Smith and me, of the performance of a sounding rocket to the case of propulsion by successive impulses from a constant-volume solid propellant rocket engine.43 We had reviewed Goddard's 1919 paper on "A Method of Reaching Extreme Altitudes" 44 and decided to find a math- ematical solution for the flight calculation problem, which Goddard had not carried out. We did this in spite of the difficult practical problem of devising a reloading mechanism for such a rocket engine, for at that time no propulsion method could be discounted. Parsons and Forman built a smokeless powder constant-volume combustion rocket motor similar to the one tested by Goddard. With it they extended Goddard's results.45 To my knowledge, no practical solution has ever been found for a long-duration solid-propellant rocket engine using the impulse technique. The use of impulses from small atomic explosions has been considered; however, no actual tests of such a system have been as yet reported. The negative conclusions we reached as regards the practicability of devising an impulse-system rocket engine for long duration propulsion made us turn to the study of the possibility of developing a composite solid propellant which would burn in a combustion chamber in cigarette fashion. Par- sons decided first to try extending the burning time of the black-powder pyrotechnic skyrocket. He finally constructed a modified black-powder 12- second, 28-pound-thrust rocket unit in 1941.46 The results of L. Damblanc of France with black-powder rockets published in 1935 were known to us.47 During the summer of 1938, Smith began work- ing in the engineering department of the Douglas Aircraft Company, where he is still employed. Arnold left Caltech for New York, and completely vanished as far as we were concerned. It was not until 1959 that I learned that he was a member of the Board of Trustees of the University of Nevada. We then corresponded until his death in 1962. Tsien was able to devote less time to the work of the project, as he was completing his doctorate under von Karman. I struggled on with Parsons and Forman, little suspecting that in the next few months the project would become a full- fledged GALCIT activity supported financially by the Federal government. We also had less time to devote to rocket research, for we had to support ourselves. Parsons and For- man took part-time jobs with the Halifax Powder Company in the California Mojave Desert, and I began to do some work on problems of wind ero- sion of soil with von Karman for the Soil Con- servation Service of the U.S. Department of Agri- culture.48 The work of the group on rocket research at GALCIT, from the beginning, attracted the atten- tion of newspapers and popular scientific journals. Since our work was not then classified as "secret," we were not averse to discussing with journalists our plans and results. There were times that we were abashed by the sensational interpretations given of our work, for we tended to be, if any- thing, too conservative in our estimates of its implications.49 The fact that our work was having a real impact in America came from two sources. In May 1938, von Karman had received an inkling that the U.S. Army Air Corps (now the U.S. Air Force) was becoming interested in rocket propulsion; as I will indicate later, however, it was only at the end of the year that we learned why. Then in August 1938, Ruben Fleet, president of the Consolidated Aircraft Company of San Diego, California, approached GALCIT for information NUMBER 10 125 on the possibility of using rockets for assisting the take-off of large aircraft, especially flying boats. I went to San Diego to discuss the matter, and pre- pared a report, "The Rocket Motor and its Applica- tion as an Auxiliary to the Power Plants of Con- ventional Aircraft," no in which I concluded that the rocket engine was particularly adaptable for assisting the take-off of aircraft, ascending to operat- ing altitude and reaching high speeds. The Con- solidated Aircraft Company appears to have been the first American commercial organization to recognize the potential importance of rocket assisted aircraft take-off. It was not, however, until 1943 that liquid-propellant rocket engines, constructed by the Aerojet-General Corporation, were tested in a Consolidated Aircraft Company flying boat on San Diego Bay.51 In October 1938, a senior officer of the U.S. Army Ordnance Division paid a visit to Caltech, and informed our group that on the basis of the Army's experience with rockets he thought there was little possibility of using them for military purposes! I had learned during the year of the REP-Hirsch International Astronautical Prize, which was ad- ministered by the Astronautics Committee of the Societe Astronomique de France. The prize, named for the French astronautical pioneer Robert Es- nault-Pelterie (REP) and the banker rocket-en- thusiast of Paris, AndreVLouis Hirsch (1900-1962), consisted of a medal and a cash sum of 1000 francs. As the money contributed by Arnold was rapidly being used up, I decided to enter the competition by sending a paper on some of my work in the hope of augmenting the funds of the Project. Not until 1946, when in Prague, did I learn that the prize had been awarded to me in 1939.52 The out- break of the Second World War in Europe had prevented the Astronautics Committee from notify- ing me. In 1958, Andrew G. Haley (1904-1966), then president of the International Astronautical Federation, arranged for the medal to be presented to me by AndreVLouis Hirsch at the IXth Inter- national Astronautical Congress at Amsterdam, but by then the prize was worth a fraction of its former value. As it turned out, however, government sup- port for our rocket research was forthcoming before the contribution of Arnold was spent, and when I left JPL to work at UNESCO in Paris in 1946, 300 dollars still remained in the Arnold fund. In December 1938, after giving a talk entitled "Facts and Fancies of Rockets" at a Caltech luncheon of the Society of the Sigma Xi, I was in- formed by von Karman, R. A. Millikan, and Max Mason that I was to go to Washington, D. C, to give expert information to the National Academy of Sciences Committee on Army Air Corps Re- search. R. A. Millikan and von Karman were members of this Committee. One of the subjects on which Gen. H. A. Arnold, then Commanding General of the Army Air Corps, asked the Academy to give advice was the possible use of rockets for the assisted take-off of heavily loaded aircraft. In response, I prepared a "Report on Jet Propulsion for the National Academy of Sciences Committee on Air Corps Research," which contained the following parts: (1) Fundamental concepts, (2) Classification of types of jet propulsors, (3) Possible applications of jet propulsion in con- nection with heavier-than-air craft, (4) Present state of development of jet propulsion, and (5) Research program for developing jet propulsion.53 The word "rocket" was still in such bad repute in "serious" scientific circles at this time that it was felt advisable by von Karman and myself to follow the precedent of the Air Corps of dropping the use of the word. It did not return to our vocabulary until several years later, by which time the word "jet" had become part of the name of our laboratory (JPL) and of the Aerojet-General Corporation. I presented my report to the Committee on 28 December 1938, and shortly thereafter the Academy accepted von Karman's offer to study, with our GALCIT Rocket Research Group, the problem of the assisted take-off of aircraft on the basis of available information, and to prepare a proposal for a research program. A sum of 1,000 dollars was provided for this work. It is interesting to note that when Caltech obtained the first gov- ernmental support for rocket research, Jerome C. Hunsaker of the Massachusetts Institute of Tech- nology, who offered to study the de-icing problem of windshields, which was then a serious aircraft problem, told von Karman, "You can have the Buck Rogers' job." 54 Parsons and Forman were delighted when I returned from Washington with the news that the work we had done during the past three years was to be rewarded by being given government financial support, and that von Karman would join us as 126 SMITHSONIAN ANNALS OF FLIGHT director of the program. We could even expect to be paid for doing our rocket research! Thus in 1939 the GALCIT Rocket Research Project became the Air Corps Jet Propulsion Re- search Project. In 1944 I prepared a proposal for the creation of a section of jet propulsion within the Division of Engineering at Caltech. It was decided that it would be premature to do so. Instead, von Karman and I founded JPL. Of the original GALCIT Rocket Research Group only I remained at Caltech during the whole period, although Tsien had returned from M.I.T. in 1943 to work with us again. Parsons and Forman were employed, beginning in 1942, by the Aerojet-Gen- eral Corporation; Smith was at the Douglas Air- craft Company; and Arnold's whereabouts were then unknown to us. In conclusion, I wish to express my appreciation to William Bollay and A. M. O. Smith for their help to me during the preparation of this memoir, to Mrs. Robert H. Goddard for granting me per- mission to quote from my correspondence with her husband, to Lee Edson for providing me with text from Th. von Karman's autobiography before its publication, and to George S. James for retriev- ing several references and illustrations used in the text. NOTES Under the title O nauchno issledovatel'skoy rabote gruppi GALCIT v 1936-1938, this paper appeared on pages 69-84 of Iz istorii astronavtihi i raketnoi tekhnihi: Materialy XVIII mezhdunarodnogo aslronavticheskogo kongressa, Belgrad, 25- 29 Sentyavrya 1967 [From the History of Rockets and Astro- nautics: Materials of the 18th International Astronautical Congress, Belgrade, 25-29 September 1967], Moscow: Nauka, 1970. 1. Guggenheim Aeronautical Laboratory—The First Twenty-Five Years (Pasadena: California Institute of Tech- nology, 1954). 2. Theodore von Karman (with Lee Edson), The Wind and Beyond (Boston: Little, Brown and Co., 1967). 3. Frank L. Wattendorf and Frank J. Malina, "Theodore von Karman, 1881-1963," Astronautica Acta, vol. 10, p. 81, 1964. 4. Eugen Sanger, "Neuere Ergebnisse der Rakenflugtech- nik," Flug, Sonderheft 1 (December 1934), Vienna, H. Pittner. 5. William Bollay, "Performance of the Rocket Plane," GALCIT Rocket Research Project, Report 5, 27 March 1935; "Rocket Plane Visualized Flying 1200 Miles an Hour," Los Angeles Times, 27 March 1935. 6. F. J. Malina, "The Jet Propulsion Laboratory: Its Ori- gins and First Decade of Work," Spaceflight, September 1964, pp. 160-65; "Origins and First Decade of the Jet Propulsion Laboratory," in The History of Rocket Technology, edited by Eugene M. Emme (Detroit: Wayne State University Press, 1964), pp. 46-66; and "The Rocket Pioneers," Engineering and Science, vol. 31, no. 5 (February 1968), pp. 9-13 and 30-32. 7. Th. von Karman and F. J. Malina, "Los Comienzos de la Astronautica," ch. 1 in Ciencia y tecnologia del espacio (Madrid: I.N.T.A.E.T., 1967). F. J. Malina, "A Short History of Rocket Propusion up to 1954," in O. E. Lancaster, Jet Pro- pulsion Engines, vol. 12, High Speed Aerodynamics and Jet Propulsion (Princeton: Princeton University Press, 1959). 8. See note 4. 9. Th. von Karman, "Jet Assisted Take-off," Interavia, vol. 7, 1952, pp. 376-79; and The Wind and Beyond (see note 2), pp. 236-38. 10. The Wind and Beyond, pp. 234-35 and 238-40. 11. "Undergraduates Plan Rocket Study with New Society," Science Newsletter, vol. 31, 8 May 1937, p. 296; and "Notes and News," Astronautics, no. 39, January 1938, pp. 2 and 16. 12. Milton Lehman, This High Man (New York: Farrar, Straus and Co., 1963), pp. 234-35. 13. Esther C. Goddard and G. Edward Pendray, Editors, The Papers of Robert H. Goddard (New York: McGraw-Hill Book Company, 1970) (hereafter cited as Papers), vol. 2, pp. 665, 746, 804-06, 834, 919; and vol. 3, pp. 1199, 1353. 14. "Excerpts from Letters Written Home by Frank J. Malina Between 1936 and 1946," (unpublished; hereafter cited as Letters). 15. Goddard, Papers, 2:1012-13, 1023. 16. See note 12. 17. Robert H. Goddard, "Liquid-Propellant Rocket Devel- opment," Smithsonian Miscellaneous Collections, vol. 95, no. 3, 10 pp., 11 pis., 16 March 1936. 18. Goddard, Papers, vol. 2, p. 1027. 19. In Smithsonian Miscellaneous Collections, vol. 71, no. 2, December 1919. 20. Goddard, Papers, vol. 2, pp. 1089-91. 21. See note 20. 22. Letters (note 14). 23. Letters (note 14). 24. Goddard, Papers, vol. 3, p. 1199. 25. Letters (note 14). 26. The Wind and Beyond (see note 2), pp. 240-242. 27. See note 4. 28. See note 19; also John W. Parsons and Edward S. Forman, "Experiments with Powder Motors for Rocket Pro- pulsion by Successive Impulses," Astronautics, no. 43 (August 1939), pp. 4-11. 29. Letters (note 14). 30. "Schematic Diagram of GALCIT Proving Stand," Astro- nautics, no. 41 (July 1938), p. 1; and, same issue, F. J. Malina, "Rocketry in California, Plans and Progress of the GALCIT Rocket Research Group," pp. 3-6. 31. F. J. Malina, Hsue Shen Tsien, Apollo M. O. Smith, and William Bollay, "Report of the GALCIT Rocket Re- search Project," Report RRP-1, Guggenheim Aeronautical Laboratory, California Institute of Technology, 1937, unpublished. 32. F. J. Malina and A. M. O. Smith, "Flight Analysis of a Sounding Rocket," Journal of the Aeronautical Sciences, vol. 5, 1938, pp. 199-202. 10. NUMBER 10 127 33. Letters (note 14). 34. Willy Ley and Herbert Schaefer, "Les Fusees volantes meteorologiques," L'Aerophile, vol. 44, 1936, pp. 228-32. 35. F. J. Malina, "Characteristics of the Rocket Motor Unit Based on the Theory of Perfect Gases," Journal of the Franklin Institute, vol. 230, no. 4, 1940, pp. 433-54. 36. J. W. Parsons, "A Consideration of the Practicability of Various Substances as Fuels for Jet Propulsion," GALCIT Rocket Research Project, Report 7, 10 June 1937, unpub- lished. 37. F. J. Malina and J. W. Parsons, U. S. Patents 2,573,471, 2,693,077, and 2,774,214. Originally filed 8 May 1943. 38. See note 6. 39. A. M. O. Smith in letter to the author, 29 December 1966. 40. See note 2 and also 42, below. 41. A. Bartocci, "La forza di reazioni neU'efflusso di gas," L'Aerotecnica, March 1938. 42. F. J. Malina, Doctor's Thesis, California Institute of Technology, 1940. 43. H. S. Tsien and F. J. Malina, "Flight Analysis of a Sounding Rocket with Special Reference to Propulsion by Successive Impulses," Journal of the Aeronautical Sciences, vol. 6, 1938, pp. 50-58. 44. See note 19. 45. See Goddard, Papers, vol. 3, p. 1199; and The Wind and Beyond (note 2), pp. 240-42. 46. See note 6. 47. Louis Damblanc, "Les fusees autopropulsives a explo- sifs," L'Aerophile, vol. 43, 1935, pp. 205-09, 241-47. 48. The Wind and Beyond (note 2), pp. 206-07. 49. See note 5 and "Designs Rocket Ship to Fly at 4,400 Miles an Hour," Chicago Daily News, 12 April 1935; "Pasa- dena Men Aim at Rocket Altitude Mark," Pasadena Star News, 15 July 1938; Scholer Bangs, "Rocket Altitude Record Sought," Los Angeles Examiner, 15 July 1938; William S. Barton, "Our Expanding Universe," Los Angeles Times, 26 November 1939; and "Seeking Power for Space Rockets," Popular Mechanics, August 1940, pp. 210-13. 50. F. J. Malina. "The Rocket Motor and Its Application as an Auxiliary to the Power Plants of Conventional Air- craft," GALCIT Rocket Research Project, Report 2, 24 August 1938, unpublished. 51. C. W. Schnare, "Development of ATO and Engines for Manned Rocket Aircraft," American Rocket Society, Preprint 2088-61, p. 7; and R. C. Stiff, Jr., "Storable Liquid Rockets," American Institute of Aeronautics and Astronautics, Preprint 67-977, p. 2 and fig. 11. 52. Prix et medailles descernes par la Societe, Bulletin de la Societe Astronomique de France, vol. 53, 1939, p. 296. 53. F. J. Malina, "Report on Jet Propulsion for the Na- tional Academy of Sciences Committee on Air Corps Re- search," (Jet Propulsion Laboratory Report, Misc. No. 1), 21 December 1938 (unpublished). 54. Review by Th. von Karman of C. M. Bolster, "Assisted Take-off of Aircraft" (James Jackson Cabot Fund Lecture, Norwich University, Northfield, Vermont, Publication no. 9, 1950.—Ed.), Journal of the American Rocket Society, no. 85, June 1951, p. 92; The Wind and Beyond (note 2), p. 243. 48. 48. 13 My Contributions to Astronautics HERMANN OBERTH, German Federal Republic As a boy of eleven during the winter of 1905-06, I read Jules Verne's From the Earth to the Moon and A Trip around the Moon. If we disregard the novelistic side of these books, the following essential parts remain: Three travelers were shot in a projectile to the moon with a giant gun, called the "Columbiade." It was planned to fall onto the moon, easing the fall with powder rockets. Since the book was written in 1860, other types of rockets were unknown. The projectile, however, missed the moon and returned in an astronomically impossible, but literally very interesting, trajectory to the earth, falling onto the Pacific from which it was recovered. I was fascinated by the idea of space flight, and even more so, because I succeeded in verifying the magnitude of the escape velocity. Although I had not yet learned anything about infinitesimal cal- culus, by that time I did have the following in- formation: In high school we had learned the laws of free fall. Moreover, we had learned that at an altitude of 6370 km (two radii away from the center of the earth) gravity is only a quarter, and at an altitude of n radii from the center it is only \/n2 as great as it is on the surface of the earth (one radius distance from the center). I then divided the distance into intervals so small that gravity could virtually be considered as a constant, and I calculated the velocity increase for the greatest accelerations in these intervals. Then I did the same for the smallest accelerations of gravity in these intervals. In this manner, I found that the escape velocity of 12,000 yards per second, which Jules Verne had used, was indeed within these two limits. Likewise I found that the time of flight was correct, if it is assumed that the projectile was traveling at minimum velocity. Nevertheless, I soon saw that space flight in this way was impossible. Apart from all questions of technical rationality there was one physiological impossibility. Sitting in a car which is accelerating, we are pressed back in our seats. The greater the acceleration, the more intense the pressure. If the acceleration were as great as that of free fall, that is, 9.8 m/sec2, the pressure experienced by a body would equal its own weight. With increasing ac- celeration, the ratio would increase. Assuming it were possible to reach a velocity of 11,000 m/sec at a distance of 300 m, this pressure would be more than 20,000 times as much as the passenger's own weight. Against this handicap Jules Verne proposed a water buffer; and he succeeded with it, too—on paper, at least! Actually, this solution would be worthless, since man's internal organs could not tolerate this acceleration. Therefore, shooting some- one into space with a gun would not work, and I had to look for different kinds of space ships. Aside from some impracticable ideas, I was pushed more and more towards rocket propulsion. I cannot say that I favored it very much, because of the danger of explosion. I was also worried about the disproportion between the propellant to be taken along and the rest of the mass of the space- craft; but I saw no other way out. Jules Verne's idea of retarding the fall onto the moon by rockets had surprised me very much in the beginning, because there was nothing the escap- ing gas could push against. But, I said to myself: When someone jumps from a boat to the shore, the boat will receive an impulse in the opposite direction. If we place a pole in outer space, away from the earth's atmosphere and field of gravita- tion, and move it in a certain direction with a 129 130 SMITHSONIAN ANNALS OF FLIGHT certain speed, it will maintain its direction and speed as long as nothing else happens. But, when a space pilot, sitting on the pole, cuts little pieces off the end of the pole, and throws them backwards, then not only will these small pieces change their speed, but also the remaining part of the pole will get an impulse in the opposite direction. The for- ward speed of the pole will be increased less if the cut-off pieces are small and move slowly, and more if the pieces are large and move at high speed. In the same way, the increase in speed would be equally high if, instead of one big piece, many small pieces were to be exhausted or thrown off. It does not matter whether these pieces push against some- thing, or whether they sail through the vacuum of space. There would also be an increase in speed if the thrown-off parts were gas molecules. The in- crease can be considerable when large quantities of gas are exhausted at high speed. In general, it is not as important how much knowledge a person has, but, rather, what he does with his knowledge. In this sense, there were many stumbling blocks in the field of rocketry. Knowl- edgeable engineers and even university professors had postulated that repulsion would not work in a vacuum. I nevertheless continued in my belief that it would prove out in actual fact. There was even a colonel, head of the German Missile Post in East Prussia, who in 1927 tried to prove the impossibility of space travel. Among other things, he said that although the law of the conservation of the center of gravity was valid, the gas would expand so much in outer space that it would lose its entire mass and therefore would not have any moment of inertia. To the contrary, I main- tained that a pound of propellant would always remain a pound of propellant, no matter how much space into which it might expand. From 1910 to 1912, I learned infinitesimal cal- culus in the Bischof-Teutsch-Gymnasium in Schass- burg. This school, more humanistic than scientific in nature, resembled a car which has only small headlights in front, but which illuminates very brightly the way it has already traveled, thus help- ing light the way for others. I also had bought the book, Mathematik fur Jedermann [Mathematics for Everybody], by August Shuster, which covered differential calculus and helped me overcome a certain lack of training. As a student I had little occasion to do experi- ments. In order to accomplish something with my time, I pondered the theoretical problems of rocket technology and space travel, and attempted to solve some of them. No one of whom I had knowledge had done so thoroughly. Dr. Goddard in 1919, for instance, wrote that it would be im- possible to express for a rocket trajectory the interactions of propellant consumption, exhaust velocity, air drag, influence of gravity, etc., in closed numerical equations.1 In 1910 I had begun to investigate these mathematical relationships and to derive the equations; these investigations were completed by 1929. One of my first discoveries was the optimum speed at which losses in performance, caused by air drag and gravity, were reduced to a minimum. I found this by a sort of differentiation process and called the term v. When a rocket rises per- pendicularly to the earth's surface with the velocity v, the air drag is equal to the weight of the rocket. If the rocket rises faster, it has to fight against its weight for a shorter time; but since the air drag increases with the square of the velocity, the total losses are greater; and if it rises too slowly, it has to fight against its own weight for a longer time. All rockets built before 1920 had flown too fast. Early rockets also were not large enough, for there is a kind of competition between the weight of the rocket and the air density. If, or example, vc — 2gH, then the optimum speed does not change at all when the rocket rises. Consequently the rocket can only escape from the atmosphere if the ratio between takeoff mass and burnout mass is infinite; that is, if the propellant weighed infinitely as much as the rest of the rocket. In this equation c denotes the exhaust velocity, H the height at which the air pressure will have decreased to \/e, which is 1 divided by the base of natural logarithms (1/2.71828 = 0.36788 of the initial value), and g denotes the acceleration of gravity. If the rocket were small, then even U would decrease with time: the air does not become thinner at the same rate at which the rocket loses weight. The rocket will, so to speak, remain stuck in the air. If the rocket, however, is big and heavy, the forces caused by the drag will be less in comparison to the other forces. In this case, v is higher, and the rocket reaches thinner layers of air sooner. For example, a cannon ball will not be retarded NUMBER 10 131 as much by a headwind as a gun bullet traveling at the same speed. If the rocket carries enough propellant, the rocket can leave the earth and even escape the earth's field of gravitation. At inclined trajectories the optimum speed is the one at which the air drag is equal to the weight times the sine of the angle at which the rocket rises. Concerning the propellant taken along, the fol- lowing rule applies: the propellant will be the more effective, the higher the exhaust velocity it can produce and the more of it that can be carried compared to the rest of the rocket mass. In space with no atmosphere, and no gravitation, the in- crease in speed V2— V1 of a rocket would equal its exhaust velocity if it were e times (i.e., 2.718) heavier with filled tanks than with empty ones. If the ratio of the masses were e times e = e2 (7.389), the increase in speed would be v2 — v1 = 2c. At a ratio of e2 times e, which means a take-off mass 20 times the burn- out mass, v.,— vl = Sc, etc. From this it can be seen that v2 — vl can well be greater than c; thus, the statement made by Professor Dr. Kirchberger and Dr. von Dallwitz-Wegner is not correct: "The pro- pellant does not even contain enough energy to lift its own weight beyond the earth's field of gravitation. How should it be able to take along the weight of the rocket, too?" 2 The fact which proves these two professors wrong is that the propellant, to a large extent, remains in the earth's field of gravitation and gives only part of its energy to the rocket in the form of thrust. Later on, the requirement for stages developed out of these formulas. If there is a small rocket on top of a big one, and if the big one is jettisoned, and the small one is ignited, then their speeds are added. Councillor Lorenz, for example, had said that he never understood this principle.3 In this case, the mass ratios have to be multiplied with each other, and when calculating the lower rocket, one has to take into account the entire mass of the upper one as payload. These are only a few examples. I had entered an entirely new field of science with these calculations and could, by using my formulas, determine the important parameters for building a rocket. This is the advantage of such algebraic formulas. An electronic brain of today will calculate infinitely faster and more accurately; but it gives only cer- tain numerical answers and not the general rela- tionship. By the way, I refer intentionally to "an electronic brain of today," because computer tech- nology is growing at such a fast rate. These ma- chines can compute, in a very short time, certain common traits that statisticians would require years to find out—if they could do it at all. No one can predict the performance of future computers. The rocket at that time resembled a talented but poor boy with a small job in a big firm. Since he is not trained, he cannot work effectively, and since he cannot produce in an outstanding manner, no one's attention is drawn to him. If some of his friends were to say, "He is capable of doing better work," the people in authority would not believe it. I am thinking of the great but entirely misunder- stood German inventor, Hermann Ganswindt, of whose inventions and tragic fate I did not learn until 1926. He invented the helicopter; the free- wheeling mechanism; and in 1895(!) he proposed a space ship powered by rocket propulsion.4 I am also thinking of that Russian high-school teacher, Konstantin Eduardovitch Tsiolkovskiy, who in 1896 also proposed a space ship powered by rocket propulsion.5 He wasn't recognized until after 1924 when, working independently, western physicists had similar ideas. Tsiolkovskiy's editor wrote in 1924: "Do we have to import everything that has already been born in our unmeasurable country and which had to perish because of neglect?"G But I can tell a story myself. In fall 1917 I made a presentation to the German Ministry of Armament and proposed a long-range rocket powered by ethyl alcohol, water, and liquid air, somewhat similar to the V-2, only bigger and not so complicated. In the appendix, I expanded the principles mentioned in the text and proved them mathematically. In spring 1918 I received my manuscript back. The reviewer apparently had not read the appendix at all, for he only answered: "According to experi- ence these rockets do not fly farther than 7 km, and taking into account the Prussian thoroughness which is applied at our missile post, it cannot be expected that this distance can be surpassed con- siderably." I also experimented at the swimming school at Schassburg. I filled a bottle a third to a half full with different liquids, corked it, and jumped with it from a springboard into the water, holding the bottle with its neck down. When I moved the tip 132 SMITHSONIAN ANNALS OF FLIGHT of the bottle slightly downward near the end of my free fall, in order to compensate for the retarding effect of the air drag, I saw that the liquids floated freely inside the bottle. While doing these experi- ments, I recognized that a human being could most assuredly endure this condition for one to two seconds. It was clear to me that he could endure weightlessness for days, physically. Whether he also could endure it psychologically was questionable. However, an experiment which, by the way, almost cost my life, brought me this confirming reassur- ance. One cold morning in fall 1911 I was all alone in our swimming pool at the school. While attempting to cross the pool under water, diagonally, I hit a wall which seemed almost perpendicular to me. Feeling that I had missed my way, I swam along that wall to the left side until I tried to rise to the sur- face again—but I could not find the surface any- where. From several encounters I finally recognized that this "wall" was the bottom. I pressed against it and got to the surface in time to give you this account today. On my way home I thought about the incident and concluded that we are informed about our orientation in space by (1) the Venier particles in the vestibule of the inner ear, (2) tensions in the muscles and tissue of our body, and (3) the parts of skin against which the ground exerts a pressure.7 Because of the cold water in the pool, and the excess of carbon dioxide in my blood, my equilib- rium sensors had become insensitive. For the same reason, the sensing of the muscles was not entirely effective any longer; and there was no surface at all touching the body since it was floating free in the water. Though the Kantian category of "above" and "below" was not ineffective, the feeling for the direction of a perpendicular line was lost. This meant that I had undergone the psycho- logical experience of weightlessness! It was not a dramatic experience such as jumping off a trampo- line and experiencing a sudden fall. Rather, it was experienced gradually by a numbing of the senses. In order to examine psychological effects, it is not necessary to create situations by real causes. It suffices to feign it to our senses. When the mother receives the news of her son's death, and believes it, she will react in exactly the same manner as if he had died; even if, in fact, he is still alive. Thus, if a psychologist wants to study the effects of such news, he does not have to kill the mother's son. In the same way, we can study the psychological effects of weightlessness if we know how to simulate it. For three years during World War I, I had access to all drugs at a hospital and a military pharmaco- logical supply station. With the help of these drugs I numbed the sense of equilibrium in my muscles and skin; so that by floating under water with my eyes closed; and by using an airhose wound around my body, I could extend the psychological experi- ence of weightlessness for hours. I noticed that I did not become nauseated when using these drugs. During an actual space flight, a rendezvous maneu- ver does not take more than a couple of hours; and during the rest of the flight, gravitation can be produced by rotation and by centrifugal force. I do not believe in the need of exposing man to unnatu- ral conditions. In my opinion, it is the aim of tech- nology to provide man with conditions in space which correspond to his nature. I have been of this opinion since I was young, so no one can talk of calcification on my part. I do not mean to say, however, that the effects on man of weightlessness over long durations should not be studied. Everything suitable for research should be investigated scientifically. But a perfect technology should not make man live in adverse conditions. Today we know that there are people who think weightlessness is a pleasant feeling and who have endured it without permanent harm. I am not surprised, but only puzzled about the little faith that was given to my observations and conclusions of so long ago. After World War I, I changed from medicine to physics and turned to some German physicists and engineers with my ideas, but without success. Today, I know why. People are too busy and overly strained. If an ordinary professor wants to do his job correctly, he first must be very fast at writing and reading, because a publication is expected of him every year, no matter whether or not he has anything to say. Second, he has to keep up to date on his discipline. In the third place, he has to be a manager and a real diplomat to maintain the status of his institute. Fourth, he must be talented in writing and presenting understandable lectures because he has to teach his students. And fifth, he has to be gifted as a research scientist; an effort that exceeds even the gift of inventing something. NUMBER 10 133 But, which human being is excellently gifted in all these fields and is able to enjoy some of those activities which often provide no monetary return? More could be achieved in science, by far, if these matters were separated from each other. People with a gift or teaching should have no other obligations than to teach. Research scientists en- dowed by God with their gift, should not be both- ered by anything else. And managing should be left to those born for it. But especially the following should be considered: People with a gift for fast and voluminous writing and reading should be employed to record everything currently known in manuals. These would be divided like the Bible into books, chapters and verses so that they could be referred to quickly. Yearly supplements should be published and from time to time the manual should be revised. I do not have to mention that such manuals should have an alphabetical index so that the author could quickly find the passage he wants to refer to. People who perform serious scientific work should be reminded not to write about anything already contained in the manual but to refer to all the passages in the manual related to their particular subject. As things stand today, the average scientist looks at the entire body of scientific knowledge like a stuffed goose looks at its food—for God's sake, no more! He studies only his special subject and is often a layman on others. He often opposes new ideas outside his specialty. If asked why he does not take interest in subjects other than his own—sub- jects in which all the world is interested—the easiest answer is, "I do not think anything of it." If he did approve of another specialty, he would have to occupy himself with the subject, and would lose valuable time in the area in which he is most pro- ficient. In his defense, it must be said that out of a thousand proposed inventions, only one, at the most, is worthy to be examined more closely! Good ideas often take decades to establish themselves. This being so, which person has not committed an error in his life? If I did not know something 20 years ago and know it today, I do not have to be treated as though I still did not know it. For in- stance, my very highly esteemed colleague, Professor Klaus Oswatitsch, is now a member of the Inter- national Academy of Astronautics, although 15 years ago he maintained that it would be unworthy of a serious scientist to occupy himself with astro- nautics, especially manned space travel. And he even carried on a controversy with me in a Salzburg periodical. In any event, it turned out to be impossible to get authoritative scientists to listen to me or to think about my early proposals. In order to force them to examine my ideas, I had to turn to interesting the public in space travel. The results of my investigations had been com- piled in a manuscript originally intended only to prove the possibility of space travel. But then I began to fear that I would be reproached with: "Dear friend, what you have calculated is all right, but today's technology cannot build such a thing." In order to avoid this reproach, I began investigat- ing solutions for problems not readily understood by an engineer of that day. I continue to be sur- prised at how much of my studies has entered modern space technology. Among them, unfortu- nately, were theoretical things I would have carried out better had I been doing the development work on the rocket. And on the other hand, sometimes I did not want to state everything I knew because I did not want to be superfluous in the future development of rockets. I wanted to work as a technician and consulting engineer. Of course, some things I did not mention were subsequently in- vented by other people, independently of me. I want to mention the swiveling motor as an example. My intention to build it can be deduced from the fact that I left out the part between the pump and the combustion chamber and rudders in the ex- planatory drawings for the construction of a rocket (Figures 1 and 2) in my first two books.8 Other things were not mentioned in order to keep these drawings from becoming too complex. For example, I knew at that time the optimum ratio of rocket stages, but mentioned it for the first time in 1941 in a secret note. At that time I knew most of the things I published in 1958 in my book Das Mondauto.0 Other things I showed in the design drawings but did not mention in the text included the bell shape of the nozzles for high expansion or the film-cooling of the thrust chambers. But it was no work of witchcraft to invent those things I had prophesied. My formulas showed me what to pursue and what to ignore. For instance, the requirement of a high exhaust velocity led logically to the use of liquid propellants because 134 SMITHSONIAN ANNALS OF FLIGHT A FICURE 1.—Model B rocket. From Oberth, Wege zur Raum- schiffahrt, 1929. they provide a greater specific impulse. From the requirement for a lightweight rocket structure came the realization that ceramic materials could not be used for rockets with liquid propellants. In these rockets the combustion chamber has to be light in weight and must have a thin wall, and the walls have to be kept cool by flowing the fuel around them. With this method, regenerative cooling is accomplished. The pressure in the combustion chamber must not be too low, otherwise the gas exhausts at too low a velocity. The tanks, however, should be under low pressure so that the walls do not have to be too thick. From this consideration the need for fuel pumps resulted. By the way, the paper also contained a relatively simple mathe- matical criterion for determining the advantage or disadvantage of using a device which increased the exhaust velocity but diminished the mass ratio of empty rocket to filled rocket. In spite of regenerative cooling I did not want the temperature of the combustion chamber to be too high, especially because the titanium and vana- dium-steel alloys of today were not known at that time. A means of decreasing the temperature of the combustion chamber without reducing the exhaust velocity is available by adding another element to the propellant which does not burn but only evapo- rates, thus creating a specifically light vapor. When combining hydrogen and oxygen, for example, the excess of hydrogen creates that effect (Esnault- Pelterie called it the "Oberth-effect"). In this way I had, in the 1920s, experimentally achieved a propulsion system which reached ex- haust speeds of 3,900 m/sec to 4,0000 m/sec. I used the propellants, however, in their gaseous state because in Transylvania I could neither obtain them in liquid form nor find means to liquefy them. I wrote about this to some friends in Vienna; whereupon a professor of the Vienna Technical University answered that I must be a fraud. He had calculated that hydrogen and oxygen, even when used in their stoichiometrically correct proportion, could not provide more than 3,200 m/sec because of dissociation. However, he did not think of the fact that dissociation is practically zero because of the excess of hydrogen and the low temperature. Pure hydrogen can be lighter and achieve a greater ex- haust velocity at low temperature than dissociated or even undissociated H20 vapor at high tempera- ture. Today the Americans use H2 and 02 in their NUMBER 10 135 FIGURE 2.—Model E rocket. From Oberth, Wege zur Raumschiffahrt, 1929. hydrogen-oxygen engines in propellant ratios of 1:4 to 1:5 (instead of the stoichiometric ratio of 1:8) and produce exhaust velocities up to 5,000 m/sec. For the same reason, I proposed to add water to the alcohol in the first stages, even though these engines do not develop the high exhaust velocities of hydrogen-oxygen engines. Water has since been used in almost all engines burning alcohol. The demand for specifically heavier fuels in the first stages, even though they do not develop such high exhaust velocities, and for lighter fuels with higher exhaust velocities in upper stages, also resulted from the mathematical formulas in my writings. I tried to avoid static reinforcements by keeping the tanks under a light overpressure internally. This principle has been applied practically to the Atlas booster by Karel J. Bossart, who developed it to technical maturity.10 Another proposal of mine which has found appli- cation is the use of parachutes for landing rocket vehicles. Later on, I had proposed electricity for the steer- ing mechanism. For example, for the speed-control system, I proposed that a mass should act against an elastic resistance; its deflection would then be a function of the acceleration. The mass was to act in such a way on a potentiometer (a variable electric resistor) that a current proportional to the accelera- tion would be produced. When this current is integrated, speed will be indicated. This instrument can also be used to close the fuel valves automati- cally, when the desired speed is reached. The attitude of the rocket was to be controlled by a gyroscope which caused the rudders to deflect by electric control as soon as the gyroscope and rocket axes were not parallel. In my book I also proposed a centrifuge, with an arm 35 meters long, to examine systematically the resistance of man to high accelerations, to train man at high accelerations, and to select among the applicants for space travel those with the best abilities. 136 SMITHSONIAN ANNALS OF FLIGHT Regarding space capsules, I proposed to paint them black on one side and leave them shiny on the other, and to turn the desired side to the sun. I also proposed a spiral tube which had the function of cleaning the air by distillation. When shadowed by the spacecraft, the tube would cool down, and condense out the wastes of the spacecraft, because they all have a higher freezing point than oxygen, nitrogen, and argon, which would remain as gases. These would first pass through a filter, and then be warmed to a convenient temperature on the sunny side of the spacecraft. The tube could be cleaned by turning the cold side to the sun and evaporating the condensates. During this process the condensates could also be retained, cooled again, and stored for certain purposes. I also proposed a giant space mirror in that book in order to offer something sensational to the reader. I had submitted this manuscript of the University of Heidelberg as a thesis for a Ph.D., but it was refused. Councillor Max Wolf, who was an astron- omer, could not accept it because it dealt mainly with physical-medical subjects; he gave me a cer- tificate, however, stating that he thought the work was scientifically correct and ingenious. With that certificate I offered my book to the publishing firm of R. Oldenbourg in Munich. This little book, which appeared in 1923 under the title Die Rakete zu den Planetenrdumen,11 fulfilled its purpose. It stimulated public interest, and numer- ous authors explained the difficult content to the layman, among them Max Valier, Otto Willi Gail, Willy Ley, Karl August von Laffert, and Felix Linke.12 In 1928 Fritz von Opel revealed his famous rocket-powered car. Maybe it will be of interest to you to know that when I visited him, his first words were, "Professor, do not judge me solely by the rocket-powered car. I do serious work, too." A rocket engine works most efficiently when the gas velocity ejected rearward is matched by the forward velocity of the vehicle. In the case of the rocket- powered car, the efficiency was very poor. Opel knew that, but he showed his rocket car for pub- licity. This, however, did not prevent Professor Kirchberger, who was not aware of that fact, from calculating the efficiency of Opel's rocket car from the consumed fuel and the power output. Then he put the result into calculations for space rockets so as to prove that space travel is impossible (or at least that he himself could not have invented it). As I said, Opel used his car only for advertising purposes, and he succeeded—public interest was very much stimulated. During the years from 1922 to 1928 I finally learned that I was not alone in my ideas regarding rocketry. As early as 1922 I had heard of Dr. Robert H. Goddard and had written to him, whereupon he sent me his publication "A Method of Reaching Ex- treme Altitudes." 13 In 1924 I heard of Konstkntin Tsiolkovskiy for the first time. In 1925 he sent me his book Rakyeta v kosmeetcheskoye prostranstvo/4 and I was helped with the translation by one of my students, Arzamanoff, a Russian emigrant. Then in 1924, the city engineer of Essen, Walter Hohmann, published his book about rocket trajectories in interplanetary space.15 He had made these calcula- tions for his own enjoyment but had not published them because he feared ridicule. When he sa^ that such far-out ideas could indeed be published, he ventured into the public limelight. One of his cal- culated trajectories was later used for the calcula- tion of the trajectory for a spacecraft to MarfsJ a;nd another for a spacecraft to Venus. In 1926 I heard for the first time of Hermann Ganswindt.16 In 1929 I wrote about him: "Germany possesses the peculiar gift of producing great men and then letting them perish through neglect!" In 1929 I published Wege zur Raumschiffahrt,17 in which I reported most of my theories on space travel and my inventions. I described manned space travel in detail, proposed the inclined trajectory towards the east for ascending space ships, investi- gated the relationships between consumption of propellant and gain of energy, commented on most of the errors in the literature of the day concerning rockets, and finally, described an electrostatic space ship. It is well known that manned space travel has required fewer sacrifices than the development of aviation. The main reason for this is that aviation meant a leap into an unknown element, whereas in space travel, most of the problems were solved theo- retically before being taken up practically. And, in all humility, I think I contributed to that with my theoretical preparatory work! The time finally came when the German scientific world had to take a stand on the question of space travel. But, believe me, I was amazed upon seeing the lack of general education, the disinterest in new NUMBER 10 137 \ 1 '-*■■■ :1 1 1 i Itfft* 1 - 1l a? 1 1 0 i if 1 r' (> ~ 1 V ■ * r ■ Jft — pp ■ . ,1, •1 5 i « LgV & J i ■ . - Sp— *■ ■ >• jy F"^'' ■ K -^ _F'V . FIGURE 3.—Set of "Frau in Mond" with (from left) Otto Kanturck (who built sets), Hermann Oberth, Fritz Lang (boy in front of him is one of the actors), the cameraman, Hermann Gans- windt, and Willy Ley. Photo from Willy Ley collection. ideas, and the vanity and self-complacency of certain people! Up to that time, subconsciously, I had en- visioned a kind of worship of scientific research; and I had considered German scientists as absolutely the best. Why, for example did Councillor Lorenz invent one objection after the other to space travel, one more senseless than the other, and why did he, as second chairman of the VDI (Association of German Engineers), make it impossible for me to comment on his objections in the VDI periodical.18 I think he did this because he had said once that space flight was impossible, and he did not want to retract his statement. He had overlooked the fact that the problem of repulsion is mainly a problem of im- pulse, that propellants not only possess chemical but also a high kinetic energy which is destroyed partly by the gas exhausting backward, but which has to re-appear somewhere; that the amount of this energy can only be calculated according to the laws of thrust; and that the rocket is always at rest with respect to itself. Another time he integrated in wrong intervals. If a student of his had done so in an examination, he probably would have failed him. About the inclined trajectory towards the east, which I had proposed, he said that every sensible human being would have to understand that a rocket will be most efficient if the thrust is always in one direction, upwards and perpendicular to the earth. In addition to Lorenz, I would like to mention a certain major from the Reich Ministry of Arma- 138 SMITHSONIAN ANNALS OF FLIGHT FIGURE 4.—Professor Hermann Oberth on the studio grounds of the UFA, during the filming of "Frau in Mond." Photo from Frederick I. Ordway III collection. ment who in 1928 still insisted to me that rockets flying farther than artillery shells would be of no military interest. Professor Dr. von Dallwitz-Wegner maintained that a change of speed of 30 m/sec2 would be ex- perienced by a man jumping off a train going at 100 km/hr.19 Apparently he confused speed with acceleration. Why do I say all this? Everything mentioned has been disproved and the people of that time are dead and forgotten. Is it necessary to exhume dead bodies? Ladies and gentlemen, I am not exhuming dead bodies. I am talking about something living! When listening to the objections of today's scientists against new inventions and discoveries, the same thing is found again. For example, let us look at the rediscovery of Atlantis by Pastor Spanuth, or at the objection against parapsychology, or at re- search on Unidentified Flying Objects. Even in the field of astronautics it appears quite often in Ger- many that people such as A. F. Staats, Hermann Langkraer, or Schonenberger go unnoticed, whereas others who cannot measure up to them get the lion's share of research funds. However, I do not want to close on a bitter note. Instead let me tell you of a personal experience that has a brighter side. First, in 1927, the Verein NUMBER 10 139 FIGURE 5.—Photo taken 5 August 1930 after Professor Oberth's successful "Kegelduse" test on grounds of Chemisch-Technische Reichsanstadt, Berlin-Plotzensee. From left: Dr. Rudolf Nebel, Dr. Ritter (of Chemisch-Technische Reichsanstadt), Mr. Bermueller, Kurt Heinisch, next man unidentifiable (almost covered by Oberth), Professor Hermann Oberth, next man unknown, Klaus Riedel ("Riedel II") in white coat, Wernher von Braun, next man unknown. Photo from Fredrick I. Ordway III collection. fiir Raumschiffahrt [Association for Space Travel] was founded in Breslau,20 and in 1928 Fritz Lang (see Figure 3), made his well-known film "Frau in Mond" (The Girl in the Moon).21 During that time I began my first firing tests at the UFA site in Berlin (Figure 4). Subsequently I received certification for the first European rocket engine firing with gasoline and liquid oxygen,22 (Figure 5). The affair, by the way, was nevertheless disgraceful. First, I was not a trained mechanic; and Henry Ford was right when he said that one should not invent an engine if one could not assemble it with one's own hands. Let me tell you, that man was right. Realizing this, I set to work and in 1932 I passed my examination as lock- smith and then taught the courses of practical engineering at the Mediasch High School. Later, I also learned design engineering. Second, my nerves were almost shattered by an explosion in the fall of 1929.23 Had I been as serene as I am today, I would have left everything as it was and cured my neurosis. But I did not want to give up the exceptional opportunity to conduct experiments, so I continued working. The explosion had made it clear to me that considerably faster combustion of gasoline and liquid oxygen was possible in a limited, narrow space; and I discovered the atomization phenomenon of burning liquid propellant droplets. This had been the only physi- 140 SMITHSONIAN ANNALS OF FLIGHT cal-technical question that had troubled me secretly. Fourteen days later I had my slit injector and nozzle. Another seven days later my cone combus- tion chamber was ready to fire. With that the door to space travel was pushed open. However, as a consequence of my tension and taut nerves I had committed several grave blunders, especially in treating people. But as I said, the combustion chamber for liquid propellants was invented, and it has been hailed as a major contribution to astronautics. I was helped with my experiments by students of the Technical University of Berlin. Among them was Wernher von Braun, who has since made space travel a reality. NOTES Under the title Mop raboty po astronavtike, this paper appeared on pages 85-96 of Iz istorii astronavtiki i raketnoi tekhniki: Materialy XVIII mezhdunarodnogo astronavtiches- kogo kongressa, Belgrad, 25-29 Sentyavrya 1967 [From the History of Rockets and Astronautics: Materials of the 18th International Astronautical Congress, Belgrade, 25-29 Septem- ber 1967], Moscow: Nauka, 1970. 1. Robert H. Goddard, "A Method of Reaching Extreme Altitudes," Smithsonian Miscellaneous Collections, vol. 71, no. 2, December 1919, p. 1: The problem was to determine the minimum initial mass of an ideal rocket necessary, in order that on a continuous loss of mass, a final mass of one pound would remain, at any desired altitude. An approximate method was found necessary, in solving this problem .... in order to avoid an unsolved problem in the Calculus of Variations. The solution that was obtained revealed the fact that surprising small initial masses would be necessary . . . .—Ed. 2. Dallwitz-Wegner, "Ober Raketenpropeller und die Unmoglichkeit der Weltraumschiffahrt mittels Raketenschif- fen" [The Rocket Propeller and the Impossibility of Space Travel by Means of Rocket Ships], Autotechnik, 1929; K. Holzhausen, "Schuss und Rakete in den Weltenraum" [Pro- jectiles and Rockets in Interstellar Space], Maschinen- Konstrukteur, vol. 61, no. 18 (15 September 1928), pp. 436- 437, and, same issue, H. Oberth, "Das Wesen der Rakete" [Principle of the Rocket], pp. 438-441.—Ed. 3. H. Lorenz, "Die Moglichkeit der Weltraumfahrt" [The Possibility of Space Travel], Zeitschrift des Vereins Deutscher Ingenieure, vol. 71, no. 19, 7 May 1927, pp. 651-657, and Supplements 1 (vol. 71, no. 32, 6 August 1927, p. 1128) and 2 (vol. 71, no. 35, 27 August 1927, p. 1236); and "Der Rakenten- flug in der Stratosphare" [Rocket Flight in the Stratosphere] and "Die Ausfuhrbarkeit der Weltraumfahrt" [The Feasibil- ity of Space Travel], Jahrbuch der Wissenschaftlichen Gesell- schaft fur Luftfahrt, 1928. Hermann Oberth, "1st die Wel- traumfahrt Mciglich? [Is Space Travel Possible], Die Rakete, no. 11 (15 November 1927), pp. 144-52, and no. 12 (15 Decem- ber 1927), pp. 163-66. Accounts of the Lorenz-Oberth debate at the WGL meeting appear in Willy Ley, Rockets, Missiles, and Men in Space (New York: The Viking Press, 1968), pp. 109-110; and Theodore von Karman, with Lee Edson, The Wind and Beyond (Boston: Little, Brown and Co., 1967), pp. 236-37.—Ed. 4. Ley, op. cit. (note 3), pp. 85-93. 5. Konstantin E. Tsiolkovskiy, "Issledovaniye mirovykh prostranstv reaktivnymi priborami [Investigation of Outer Space by Means of Reactive Devices], Nauchnoye Obozreniye [Science Review], no. 5 (May 1903), pp. 44-75, and Rakyeta v kosmeetcheskoye prostranstv [The Rocket into Cosmic Space] (Kaluga, 1924), 32 pp.—Ed. 6. Tsiolkovskiy, Rakyeta v kosmeetcheskoye prostranstv, p. iii; and W. Ley, op. cit. (note 3), p. 96.—Ed. 7. I was exposed to medical information early in life be- cause my father was a physician and a good friend of the town's physician, Dr. Fritz Kraus. We visited him very often. He was a man with an incredible amount of knowledge; and the conversations between my father and him were always highly interesting and instructive. It was stated incorrectly, therefore, in 1958 that I had acquired only a little general education at the age of 30. I was also a very eager reader of the Monthly Popular Science Journal Kosmos. 8. Oberth, Die Rakete zu den Planetenrdumen [The Rocket into Interplanetary Space] (Munich-Berlin: R. Oldenbourg, 1923), 92 pp.; and Wege zur Raumschiffahrt [Means for Space Travel] (Munich-Berlin: R. Oldenbourg, 1929), 431 pp. 9. Oberth, The Moon Car, translated by Willy Ley (New York: Harper & Brothers, 1959), 98 pp. 10. John L. Chapman, Atlas: The Story of a Missile (New York: Harper & Brothers, 1960), pp. 86-92.—Ed. 11. See note 8. 12. Valier, Der Vorstoss in den Weltenraum [The Advance into Space] (Munich-Berlin: R. Oldenbourg, 1924), 134 pp.; Gail, Mit Raketenkraft ins Weltenall: Vom Feuerwagen zum Raumschiff, [With Rocket Propulsion into Space: From Rocket Cars to Space Ship] (Stuttgart: K. Thienemann, 1928), 106 pp.; Ley, Die Fahrt ins Weltall [The Journey into Space] (Leipzig: Hachmeister & Thai, 1926); and Linke, Das Raketen-Weltraumschiff [The Rocket Spaceship] (Hamburg, 1928), 100 pp. 13. See note 1 and Esther C. Goddard and G. Edward Pendray, Editors, The Papers of Robert H. Goddard (New York: McGraw-Hill Book Company, 1970), vol. 1, pp. 485-86 and 545.—Ed. 14. See note 5. 15. Hohmann, Die Erreichbarkeit der Himmelskorper [The Attainability of Celestial Bodies] (Munich-Berlin: R. Olden- bourg, 1925), 88 pp. 16. See note 4. 17. See note 8. 18. See note 3. 19. See note 2. 20. 5 June 1927, see Heinz Gartman, The Men behind the Space Rockets (New York: David McKay, 1956), pp. 48-73. 21. Ley, Rockets, Missiles, and Men in Space (see note 3), pp. 114-24. 22. Ibid., pp. 121-24. 23. Ibid., p. 118. 10. 14 Early Rocket Developments of the American Rocket Society G. EDWARD PENDRAY, United States The first issue of the Bulletin of the American Interplanetary Society, better known later as the American Rocket Society,1 appeared in June 1930. It consisted of four single-spaced mimeograph pages, carrying news of the Society's founding on 4 April of the same year; * a summary of a paper on "The Historical Background of Interplanetary Travel" by Fletcher Pratt, the writer and historian; an item about the tragic death of the German rocket pio- neer, Max Valier, which had occurred in the previ- ous month; a prediction by Robert Esnault-Pelterie, the French aircraft builder and inventor, "A trip to the Moon may be possible within fifteen years"; and an announcement that the Society was undertaking "a survey of the entire field of information relating to interplanetary travel." This latter survey was the beginning of the So- ciety's program to promote the development of rockets. As planned, it was to consist of a series of studies by various members of the Society, sum- marizing the literature then available on the physics, chemistry, technology, and history of rockets, as well as current thinking on what later came to be known as astronautics. Several of these summary papers were completed and presented at subsequent So- ciety meetings. Others were begun but later aban- doned, for it early became evident that a wide gap existed between current ideas and technical litera- ture about rockets and the practical task of develop- ing them as potential vehicles for space exploration. Dr. Robert H. Goddard, the American rocket and space flight pioneer, was then at work on his highly significant rocket development in Massachusetts, and was soon to continue it on a greatly increased scale in New Mexico, financed by a grant from Daniel Guggenheim. Dr. Goddard had published very little, his principal paper having been "A Method of Reaching Extreme Altitudes," brought out by the Smithsonian Institution in December 1919, dealing entirely with solid propellant rock- ets.3 From time to time newspaper stories indicated that he was making considerable progress, but mem- bers of the Society could learn almost nothing about the technical details of this work. There had appeared in American newspapers and popular magazines, however, numerous articles about rocket experiments in other countries, espe- cially in Europe. These included the work of Oberth, Heylandt, Valier, Esnault-Pelterie, the Verein fiir Raumschiffahrt, and others. At the time of the Society's founding I had been elected vice-president, with the assignment of help- ing to get a research program going. Early in 1931 it became possible for Mrs. Pendray and me to go abroad, and we planned our trip in such a way as to enable us to see, we hoped, what some of the European experimenters were doing. The Society named us its official representatives, but in view of the state of the treasury, we paid for the trip our- selves. Mrs. Pendray was one of the twelve founders of the Society, which number also included myself. After some unsuccessful attempts to get in con- tact with Darwin O. Lyon * in Italy and Robert Esnault-Pelterie in France, both of whom were away at the time of our arrival, our journey at length brought us to Berlin, where we found Willy Ley very much at home and eager to show us the work of the Verein fiir Raumschiffahrt, which was engaged in a modest experimental program at the "Raketenflugplatz," its "rocket flying field" at Reinickendorf on the outskirts of Berlin. We had not previously met Ley, one of the founders, and at that time secretary of the VfR, but had corresponded with him. There was, however, 141 142 SMITHSONIAN ANNALS OF FLIGHT something of a communications problem; Ley's English wasn't very good at that time, and our German was nonexistent. It was not easy to carry on technical conversations, but with the aid of drawings, sketches, and patient explanation on Ley's part, we managed it after a fashion.5 Ley and his VfR associates, who included Ru- dolph Nebel, Klaus Riedel, and several others, then gave us the most memorable experience of the en- tire trip—a proving-stand test (Figure 1) of a small liquid-propellant rocket motor employing liquid oxygen and gasoline. Mrs. Pendray and I were not aware at the time that Goddard's successful shots since 1926 had been accomplished with liquid propellants, and this experiment at the Raketen- flugplatz was the first of its kind we had witnessed. Upon our return I reported fully to the Society, on the evening of 1 May 1931, both the method and the promise of the German experiments.6 A few days later Hugh F. Pierce, who was subse- quently to become president of the Society and one FIGURE 1.—Author in 1931 visiting the proving ground of the Verein fiir Raumschiffahrt near Berlin. An early type of liquid-fuel rocket motor is in the thrust frame. From left, Willy Ley, Klaus Riedel, Rudolf Nebel, G. Edward Pendray. of the four original founders of Reaction Motors, Inc., proposed that the Society delay no longer the beginning of its own experimental program. An Experimental Committee was formed, with myself as chairman, and the Society's Rocket No. 1 was designed by Pierce and me. It was patterned in general after the "Two-Stick Repulsor" rocket of the VfR, designs for which I had discussed with Ley in Berlin.7 The rocket (Figure 2) was constructed in a small machine shop Pierce had established in the base- ment of the apartment house where he lived. The propellant tanks consisted of two parallel cylin- drical tubes of aluminum, each 5i/£ feet long and FIGURE 2.—ARS No. 1, during a demonstration and lecture at New York University (Washington Square Campus), in spring 1932. Hugh F. Pierce, who constructed the rocket, is packing the parachute in its container (made from a ten- cent-store saucepan) as G. Edward Pendray, co-designer of the rocket, holds the parachute. The cone-shaped nose was designed to open up at the height of the flight and eject the parachute. The parachute itself, made by Mrs. Leatrice M. Pendray from a scaled-down design for a professional aviation parachute, was of silk pongee. Photo from Pendray Collection, Princeton University Library. NUMBER 10 143 a ,*4 4*J gt/tmm RKJ^iu FIGURE 3.—a, Testing ground, on a farm loaned to the Society near Stock- ton, New Jersey, used for test of ARS No. 1 on 12 November 1932. Near the trench is Mrs. Pendray, charter mem- ber of the society and an active par- ticipant in the experimental program. Working at the wooden launching rack are Pendray (left), Pierce (rear, facing camera); David Lasser (overcoat and hat) one of the founders of the society and its first president, and Dr. William Lemkin, member of the Experimental Committee. b, Pouring liquid oxygen into the tank of ARS No. 1 preparatory to test- ing, Pendray, chairman of the ARS Experimental Committee. On brace of the launching rack is electrical ap- paratus designed by Pierce for remote ignition and release of rocket. Photos from Pendray Collection, Princeton University Library. 5* <*. &X»1 I W X ^*Ni . \ \ 0 ■■■•4 144 SMITHSONIAN ANNALS OF FLIGHT 2 inches in diameter. They were clamped at the top by a yoke, or framepiece, which supported the motor and its cooling jacket, the turn-on valves that could be operated electrically, and a cone-shaped nosepiece containing a parachute. At the rear of the rocket were four fixed vanes of sheet aluminum for guidance in vertical flight. The propellants were gasoline and liquid oxygen, forced into the motor by gas pressure at approxi- mately 300 psi. The oxygen pressure was produced by partial evaporation. The gasoline was pressur- ized by nitrogen supplied from an auxiliary tank. The parachute mechanism was kept closed by the pressure of nitrogen in the gasoline tank, and was set to spring open when the pressure dropped at the termination of firing. The motor was an alumi- num casting, 3 inches in outside diameter and 6 inches long, with walls i/2 inch thick. Loaded with fuel, this first ARS rocket weighed 15 pounds. The motor was designed to provide a thrust of 60 pounds, giving an expected acceleration of 3G at launching. The first static test of the rocket occurred on 12 November 1932, on a farm near Stockton, New Jersey.8 Members of the Society had hauled lumber and built a small wooden launching rack (Figure 3), equipped with a spring-operated measuring device. In the test the motor burned satisfactorily for a period of from 20 to 30 seconds, and provided the expected 60 pounds maximum thrust. During these ground tests, however, the rocket was accidentally damaged, and as a consequence, was never flight tested. Its fragility, and the diffi- culty of getting all the parts to operate satisfactorily at the right time—still a problem with rockets— caused the members of the experimental group to decide on a thorough reconstruction, of such a radical nature as to constitute a new rocket. This task was put in the capable hands of Bernard Smith, a young member with considerable mechan- ical aptitude, later Technical Director of the Naval Weapons Laboratory at Dahlgren, Virginia. Smith removed the superstructure containing the parachute, the water jacket, and other items that had proved to have little or no value. He clamped the motor securely between the upper portion of the two propellant tanks, substituted light balsa-wood fins for the aluminum vanes, and rounded the for- ward end of the rocket with a streamlined alumi- num bonnet containing a large inlet port for air cooling. Smith's drawing of this rocket is shown in Figure 4. This rocket, known as ARS No. 2 (see Figure 5), was shot from a temporary proving field at Marine Park, Great Kills, Staten Island, New York, on 14 May 1933.9 It reached an altitude of about 250 feet, after firing about two seconds, and was still going well when the oxygen tank exploded, appar-.. ently as the result of a stuck safety valve. It had been calculated that the rocket would reach an altitude of about a mile, but of course the bursting oxygen tank released the pressure, the motor ceased functioning, and the rocket dropped into the water of lower New York Bay, from which it was rescued by rowboat. -PRESSURE NIPPLE In spite of the accident, the members of the So- ciety's Experimental Committee considered the shot successful. It was the first liquid propellant rocket -GASOLINE TANK -DELIVERY PIPE FINS Ml FULL VIEW SECTION FICURE 4.—Design of ARS Rocket No. 2. From The Coming of Age of Rocket Power (New York: Harper & Brothers, 1945) p. 124. NUMBER 10 145 — FIGURE 5.—a, Setting the propellant valves of ARS No. 2 rocket just prior to test at Marine Park on 14 May 1933. From left, Laurence Manning, Carl Ahrens, Bernard Smith (who designed and built the rocket), G. Edward Pendray, Alfred Best, and Alfred Africano—all members of the Experimental Committee. The rocket stands in its launching tower, complete except for a nose cone which was slipped over the valve assembly just before the shot. It had no parachute or other landing equipment. The launcher was aimed with a five-degree tilt to seaward, where rocket was expected to land. b, The take-off of rocket shown in 5a. It was about 6 feet tall and weighed about 15 pounds loaded and ready for the shot. Propellants used were gasoline and liquid oxygen pressured by nitrogen drawn from the pressure cylinder standing to the right of the launcher. At the end of the countdown, when the ignition apparatus failed to work, Smith ran out and ignited it with a gasoline torch. Here, he is return- ing to the barricade. The rocket is already in the air. Note crude barricades for protection of participants and spectators. c, Post-mortem on flight shown in 5b. From left, Max Kraus, secre- tary of the Society; Pendray (behind rocket) and Smith. Photos from Pendray Collection, Princeton University Library. 146 SMITHSONIAN ANNALS OF FLIGHT Stud Attached To Parachute Box. £ Inch Pluj Water Jacket ft ' QD. Copper Tube f Off. Copper Tube ^V^AIum. Cattinj No WPI4IZ / Onus Nozzle jf Throat Diameter F/are Angle If JO' length -Zj' Angle With Axh of Rochet * £0' Jt'd. i Orasi Pipe Oxygen feed Quick Opening -Hon Return y Fuel and Oxyjen Valves f Alum. Plate hhi' Alum. Tee Connected to Tank J FIGURE 6.—Detail of ARS Rocket No. 4. From Astronautics, no. 30 (October-November, 1934), p. 3. any of us had seen get off the ground, and consider- ing the state of the art at that time, it was something of an achievement. It was not history's first operat- ing liquid-propellant rocket, of course, the Verein fiir Raumschiffahrt had anticipated us by a few months, and Goddard by seven years and two months, his first successful liquid-propellant shot having been made near Auburn, Massachusetts, on 16 March 1926.10 Following the shot of ARS No. 2, plans for new rockets began to burgeon in the Society. Designs for several were submitted, and the three most promising ones were quickly approved by the Ex- perimental Committee.11 The design designated as ARS No. 4, constructed by John Shesta and a small group he had selected to aid him, was completed first. As can be seen in Figures 6 and la, its motor was placed ahead of the center of gravity as in the case of all these early rockets, on the theory—mistaken, as it later proved —that greater flight stability could be achieved in that configuration. ARS Rocket No. 4 had a single motor with four nozzles. The nozzles were so placed as to direct the jet gases rearward but slightly away from the sides of the cylindrical gasoline tank, on the upper end of which the motor was mounted. The oxygen tank was mounted directly behind the gasoline tank, in tandem fashion. A small cylin- drical case for a parachute projected ahead of the motor, and the motor itself was encased in a water- jacket. The first attempt to fire this rocket failed.12 Ex- amination revealed that the fuel inlet ports were not large enough and the rocket, though it fired, failed to develop enough power to rise. For the second attempt, it was slightly modified by enlarg- ing the fuel ports and omitting the water jacket. The shot (Figures lb, c) occurred on 9 September 1934, also at Marine Park, Staten Island.13 The slender rocket rose from the launching rack most satisfactorily, and in flight performed excellently for a few seconds, until one of the four nozzles burned out. The rocket, which had by this time reached an altitude of several hundred feet, yawed over, went into a long, fast trajectory over New York Bay, and struck the water still vigorously; firing. Calculations based on the data of three ob- servers at triangulation stations, and confirmed by motion picture and still photographs, indicated that at its maximum the velocity of this rocket exceeded 1,000 feet per second. ARS No. 3, designed by Bernard Smith and my- self, was completed next. In this one (Figures 8 and 9), the propellant tanks were nested one inside the other, with the gasoline tank inside, surrounding a long motor nozzle, which ran the length of the rocket, and the oxygen tank on the outside, sur- rounding the gasoline tank. This design produced a compact, professional looking rocket, but it was very troublesome to construct because of the many welded seams. What was worse, it proved impossible to fuel or shoot, because the liquid oxygen, exposed to so much warm metal in the large outer tank, NUMBER 10 147 FIGURE 7.—a, Preparing for a ground firing test of ARS No. 4 at Marine Park in summer 1934. From left, John Shesta, designer and builder of the rocket; Carl Ahrens, member of the group which aided in its construction; and Pendray. In this preliminary version, no means were provided for cooling the four nozzles of the rocket motor. The test indicated need for several modifications, including addition of a water jacket to cool the nozzles. b, ARS No. 4 in flight at Marine Park on 9 September 1934. It emerged from the launcher satisfactorily, and performed very well for the first few seconds, reaching an altitude of several hundred feet, at which point one nozzle burned out, causing the rocket, still firing rapidly, to tilt over toward New York Bay, where it struck the water at a velocity that observers at three triangulation stations estimated to be in excess of 1,000 feet per second. c, Post-mortem on flight shown in Figure 11. Shesta, left, holds the propellant-tank portion of the rocket; Pendray points to the damaged but unopened parachute case. Photos from Pendray Collection, Princeton University Library. 148 SMITHSONIAN ANNALS OF FLIGHT A--combustion chamber B--expansion nozzle C--gasoline tank D--nitrogen pressure tank E—oxygen tank F--venturi tube G--parachute and instrument compartment H--overall view a y_ • FIGURE 9.—ARS Rocket No. 3, at Marine Park for launch attempt in September 1934. From left, Shesta, Pendray, and Smith. The gasoline tank is being pressurized with nitrogen through a valve in the cone. The oxygen fill-hole is visible just below the pressure inlet. Photo from Pendray Collection, Princeton University Library. FIGURE 8.—Detail of ARS Rocket No. 3. From Astronautics, no. 27 (October 1933), p. 3. simply evaporated and blew out of the fill-hole as fast as it could be poured in.14 The other rockets which had been designed by Committee members were in various stages of con- struction, but one by one they were abandoned, for it had become clear that building and shooting whole rockets, when so many components—particu- larly the motor—were in such an unsatisfactory state of development, was really not productive. The Experimental Committee had already devised a small proving stand for individual motor tests, with a view to developing a motor that would work reliably and not burn out. John Shesta designed this first ARS proving stand, and in constructing it used the tanks, valves, and other parts of his rocket, ARS No. 4. With this equipment the Society then began a long, often discouraging, but finally successful series of motor development tests. These were conducted at various places and sometimes under great diffi- culties because, in the vicinity of New York, rocket shots or motor tests were not welcomed by neigh- bors, or approved by the police, and there was no way of obtaining permission to carry on such ex- periments in peace. As a consequence the Society performed many of these tests under some harass- ment, and found frequent and unannounced mov- ing of the testing ground to be a wise and sometimes necessary precaution. Despite these problems, the tests provided much data, increasing sophistication, useful experience and know-how, and finally cul- minated in the development of a practical liquid- cooled regenerative motor designed by James H. Wyld, a long-time member of the Experimental NUMBER 10 149 FIGURE 10.—Liquid-propellant motor under test at the ARS testing ground at Crestwood, New York, in 1935. Dials on the panel mounted on a sawhorse registered pressure in each propellant tank and in the motor, thrust, and the time in seconds. Motion pictures of dials preserved data for later study. Photo from Pendray Collection, Princeton University Library. Crestwood.17 A Nichrome nozzle stood up well in this series, but not perfectly. All the others burned out. A third series was shot at Crestwood on 25 August 1935. There were five runs, and this time various fuels as well as nozzles and cooling systems were tried.18 A fourth series of tests was made at the same place soon afterward, on 20 October 1935.19 By this time a great deal of information had been obtained. It had been definitely shown that water would not work effectively as a coolant in these small motors, and also that alcohol was a better fuel for small motors than gasoline. It began to be clear that no uncooled motor, of whatever available material, would stand up under more than a few seconds of firing, and that some dynamic means of cooling must be devised. The tests also indicated .//icimve Moult i m Tiroa/ />/'*/#. /A M J6*4 fan. "J/ * Duralumin *5ec//hn3 Fue,' Fee of Copper lute £ m /'/?. Committee. Development of this motor led directly to the founding on 18 December 1941 of Reaction Motors, Inc., later a division of Thiokol Chemical Corporation, by Lovell Lawrence, John Shesta, James H. Wyld, and Hugh F. Pierce, all of whom had been active in the Society's experimental pro- gram.15 Until the beginning of these tests the Society had been using cast aluminum motors, some cooled with water, others depending on the metal mass to soak up heat during the relatively short period of firing. In the proving stand tests, motors and nozzles of carbon steel, stainless steel, Nichrome, carbon, "hard-surfacing" metals, and other allegedly heat- resistant materials were tried. Various members suggested tests to be run, or constructed motors to be tested. In the first series of runs undertaken at Crest- wood, New York, a suburb of New York City, on 21 April 1935, five types of motors were tested (Fig- ure 10), but none stood up.16 Three months later, a new series of motors was ready. To simplify changing styles, shapes, and nozzle material on the proving stand, a "sectional motor" had been con- structed (Figure 11), the nozzle and body sections of which could readily be replaced by others of different shape or material after each run. Six runs were made in the second series of tests, also at —~«=53 FIGURE 11.—Segmented liquid-propellant rocket motor made to facilitate tests of various motor shapes and materials. By increasing or reducing the number and shape of segments, the size and shape of the combustion chamber could be quickly altered. Nozzles of various shapes and materials could also be readily tested. The design and the actual motor and alternative parts were by Shesta, in late 1935. From Pendray Collection, Princeton University Library. 150 SMITHSONIAN ANNALS OF FLIGHT 3YLPHON BELLOWS CHAMBER PRESSURE GAGE 0-300 REACTION GA6C o-eoo~ EMCROCMCY tteUhSE \h\LV£ QUICK OPENING AMERICAN ROCKET SOCIETY TESTING STAND I SHEET NO- ONE SCHEMATIC PIPING UtYOvf ttes£*vr NtT/WKN FOR PHOT wuve DESIGNED BV ' JOHN 3HEZTA H. FBAMMLIN PtCRCC DRAWN ay men iiMecm it a.* - ai FIGURE 12.—Schematic Diagram of Proving Stand No. 2. From Astronautics, no. 42 (February 1939), p. I. that the Society's first proving stand, while practical for short runs of motors of less than one hundred pounds thrust, was too small for the sort of tests now indicated. Shesta was asked to build a new, bigger and better stand, aided by Wyld, Alfred Africano, Peter van Dresser, and others. The group immediately started work on the project.20 During the period required for completion of the new stand (Figures 12 and 16), the Experimen- tal Committee turned to the problem of aerody- namic design, and began a series of tests, with solid-propellant rockets of many sizes and shapes, undertaken to determine empirically some of the principles of rocket stability and guidance in flight, as well as the mechanics of catapults and other launching schemes, flight stabilization devices, and parachutes and parachute releases. These tests were carried on at several sites, prin- cipally one near Pawling, New York. The solid- propellant rocket vehicles tested, shown in Figures 13 and 14, were made by members of the Society, and consisted of head-drive and tail-drive types, long bodies, short bodies, finned and unfinned rockets, and many other varieties all propelled by commercial skyrocket motors. The tests continued at intervals over about four years, beginning in the summer of 1935 and continuing until November 1939. The results of all these tests were reported in detail in Astronautics.21 During the latter part of this period the liquid- NUMBER 10 151 FIGURE 13.—H. F. Pierce, with solid-fuel rockets of various designs tested by the Committee to determine the best aerodynamic shape and other characteristics of high-altitude rockets. These tests took place principally at a site near Pawling, New York, where this picture was taken in 1935, during one of the earliest series. These rockets and those in Figure 14, were constructed by various members of the Ex- perimental Committee and were powered by commercial 4-pound and 6-pound skyrocket motors. FIGURE 14.—Members of the ARS Experimental Committee at Midvale, New Jersey, in summer 1937. From left, Shesta, Healy, Pendray, and Africano. Photos from Pendray Collection, Princeton University Library. propellant motor tests were resumed, and now be- gan to repay the effort. Motors of increasing effec- tiveness and sophistication began to appear for testing. The Wyld regenerative motor (Figure 15) most successful of all, was first presented in idea form in an article by Wyld in the April 1938 Astronautics. The same issue carried an article describing a new experimental motor by Midship- man Robert C. Truax of the United States Naval Experiment Station, and an account of its per- formance at tests carried out at Annapolis.22 Shortly after disclosing his idea, Wyld constructed a working model of his motor. It received its first test on the Society's new proving stand (Figure 16) at New Rochelle, New York, on 10 December 1938, delivering a thrust of somewhat over 90 pounds and producing a jet velocity of well over 6,000 feet per second. Because of an oxygen shortage at the test site that day, the first run was brief—only about 13i/^ seconds.23 Also tested, earlier on this day, were a tubular monel motor built by Pierce and a tubular regenerative motor submitted by Truax. The Wyld motor (Figure 17) was subsequently tested more fully in runs on the ARS No. 2 proving stand at Midvale, New Jersey, on 8 June 1941,24 and again on 22 June and 1 August.25 Other interesting motors also tested on these occasions included those submitted by Africano (Figure 18),26 with the So- ciety, co-winner of the REP-Hirsch Prize in 1936;27 by Robertson Youngquist (Figure 19), then a stu- 152 SMITHSONIAN ANNALS OF FLIGHT LIQUID OXYGEN JACKEK ^UNER - """> ( COMBUSTION SPACE MOTOR HEAD FIGURE 15.—Design for the Wyld liquid-propellant rocket motor, the first successful regenerative motor of its type, and culmination of the American Rocket Society's long series of experiments aimed at developing an efficient, burnout- resistant rocket motor. From Astronautics, no. 40 (April 1938), p. 11. dent at the Massachusetts Institute of Technol- ogy; 28 and by Nathan Carver, a long time member of the Society.29 Active experimentation by the So- ciety and its Experimental Committee as a group ceased after the 1 August 1941 tests. A photograph of the Wyld motor in operation during this last test series is shown in Figure 20. During the experimental period, several other rockets and motors were built and tested as well by members individually, including Pierce, Constan- tine P. Lent, and others.30 On 2 February 1936 a well-publicized "mail rocket" shot occurred at Greenwood Lake, a small body of water which lies on the border of the states of New York and New Jersey. The project, sponsored by F. W. Kessler, a Brooklyn philatelist, was designed by Dr. Alexander Klemin, of the Guggenheim School for Aeronautics at New York University, and a group of associates including Pierce, Carver, and Ley.31 Two rockets— actually small gliders equipped with liquid-propel- lant rocket motors—were prepared for the shot. The excessive power of the motors, and other mechanical problems, caused the gliders to perform erratically, but one craft nevertheless succeeded in crossing the ice of the lake from one state to the other, thus validating the regular postage and special rockets stamps on the mail they carried. Reaction Motors, Inc., continued its successful development of the Wyld motor, at first with the aid of the Society's second proving stand, borrowed from the ARS for that purpose. The Society later formally presented the stand to RMI's historical museum, and in 1965 RMI in turn presented it to the National Air and Space Museum of the Smith- sonian Institution, in Washington, D.C. FIGURE 16.—The American Rocket Society's second proving stand for tests of liquid-propellant motors. Larger, sturdier, and with a larger propellant capacity than the first, it was constructed by John Shesta, aided by several other members of the ARS Experimental Committee. The series, date and run were chalked on the blackened board at the right (date of this test was 10 December 1938). The dials registered pressure in the propellant tanks and motor, thrust, time in seconds, and other data, all preserved on motion picture for later study. From left, Shesta (behind the stand), Louis Goodman, and Alfred Africano. Photo from Pendray Col- lection, Princeton University Library. The end of active rocket experimentation on the part of the Society was brought about principally by the imminence of World War II; the develop- ment of renewed interest by the United States mili- tary authorities in rockets, particularly solid pro- pellant rockets; and the realization by most of us that small-scale development and testing such as could be done by the Society, with the resources available to it, had been carried about as far as was FIGURE 19.—MIT motor of Robertson Youngquist during test. NUMBER 10 153 FIGURE 17.—James H. Wyld and a model of his liquid-propellant regenerative rocket motor at Midvale, New Jersey, on 8 June 1941, just prior to a successful test of the motor. In subsequent tests on the ARS No. 3 proving stand, which provided larger fuel capacity and hence longer runs, the Wyld motor did not burn out, and it delivered a thrust of somewhat more than 90 pounds and a jet velocity of well over 6,000 feet per second. FIGURE 18.—H. F. Pierce making final adjustments preparatory to testing a large liquid-propellant motor, designed and constructed by Alfred Africano, on the ARS No. 3 proving stand on 22 June 1941. Photos from Pendray Collection, Princeton University Library. 154 SMITHSONIAN ANNALS OF FLIGHT FIGURE 20.—Wyld motor in action. From Astronautics, no. 50 (October 1941), p. 8. possible: subsequent development would necessarily depend on massive support, large-scale engineering teamwork, and government interest. In the end, so it proved. Meanwhile the American Rocket Society con- tinued to develop rapidly as a technical society, especially after about 1944. By 1 February 1963, when it merged with the Institute of the Aerospace Sciences to form the American Institute of Aero- nautics and Astronautics, the American Rocket Society had more than 20,000 members.32 The combined organization, of course, is now almost twice that size, and is, I believe, the largest tech- nical society in the world devoted to the more rapid development of the related sciences of aeronautics and astronautics. NOTES Under the title Ranniy period deyatel'nosti Amerikanskogo raketnogo ovshchestva, this paper appeared on pages 97-108 of Iz istorii astronavtiki i raketnoi tekhniki: Materialy XVHI mezhdunarodnogo astronavticheskogo kongressa, Belgrad, 25- 29 Sentyavrya 1967 [From the History of Rockets and Astro- nautics: Materials of the 18th International Astronautical Congress, Belgrade, 25-29 September 1967], Moscow: Nauka, 1970. G. Edward Pendray has been closely associated with the development of rockets since 1929, being one of the founders and a director and advisor of the American Rocket Society (which merged in January 1963 with the Institute of the Aerospace Sciences to form the American Institute of Aero- nautics and Astronautics). He wrote the influential book, The Coming Age of Rocket Power (New York: Harper & Brothers, 1945), in which many of the details here presented are to be found on pages 118-130. With Mrs. Esther C. Goddard, he edited a collection of Dr. Goddard's research notes published as Rocket Development: Liquid-Fuel Rocket Research, 1929-1941 (New York: Prentice-Hall, Inc., 1948; rev. ed., paperback, 1961) and also with Mrs. Goddard, he recently completed editing The Papers of Robert H. Goddard (New York: McGraw-Hill Book Company, 1970). 1. "The Forthcoming Annual Meeting," Astronautics (offi- cial publication of the American Interplanetary Society), no. 28 (March 1934); reprinted edition (New York: Kraus Reprint Corporation, 1958), p. 7. The name of the American Inter- planetary Society was changed to the American Rocket Society at the annual meeting on the evening of 6 April 1934. 2. G. Edward Pendray, "The First Quarter Century of the American Rocket Society," Jet Propulsion (Journal of the American Rocket Society), vol. 25, no. 11 (November 1955), p. 586. 3. Robert H. Goddard, "A Method of Reaching Extreme Altitudes" (Smithsonian Miscellaneous Collections, vol. 71, no. 2, 69 figs., 11 pis., December 1919) and "Liquid Propellant Rocket Development" (ibid., vol. 95, no. 3, 10 pp., 11 pis., 16 March 1936) were republished by the American Rocket Society in one volume entitled Rockets in 1945, with a new foreword by Dr. Goddard and Pendray. Goddard began correspondence with Pendray early in the history of the American Interplanetary Society. Both men wrote each other and occasionally met throughout Goddard's life. One result of this association was the American Rocket Society combined edition of Goddard's classic reports. (See Esther C. Goddard and G. Edward Pendray, editors, Tl :■ Papers of Robert H. Goddard (New York: McGraw Hill Book Company, 1970), vol. 2, pp. 795-96, 1073, 1074 and 1084; and vol. 3, pp. 1346, 1540-45, 1548-56, 1581, and 1598—Ed.) 4. "Has Two-Step Rocket Ready," Bulletin, American Interplanetary Society, no. 6 (January 1931); reprinted edition (New York: Kraus Reprint Corporation, 1958), p. 1; "Ameri- can Rocket Pioneers, No. 3, Dr. Darwin O. Lyon," Journal of the American Rocket Society, no. 61 (March 1945), p. 11. 5. Willy Ley, in a footnote on page 129 of his Rockets, Missiles, and Men in Space (New York: Viking Press, 1968), comments on a misunderstanding regarding the evolution of the German VfR Miraks which apparently resulted from these conversations. 6. Pendray, "The German Rockets," Bulletin, American Interplanetary Society, no. 9 (May 1931), pp. 5-12. 7. Pendray, "The Conquest of Space by Rocket," Bulletin, American Interplanetary Society, no. 17 (March 1932), pp. 3-7. Discusses the evolution of ARS Rocket No. 1. 8. Pendray, "History of the First A.I.S. Rocket," Astro- nautics, no. 24 (November-December 1932), pp. 1-5; and Pendray, "Why Not Shoot Rockets?" Journal of the British Interplanetary Society, vol. 2, no. 2, 1935, pp. 9-12. This account discusses the cost of ARS Rocket No. 1. 9. Pendray, "The Flight of Experimental Rocket No. 2," Astronautics, no. 26 (May 1933), pp. 1-13. 10. Goddard, "Liquid-Propellant Rocket Development" (see Note 3), pp. 2-3. 11. "Three New Rockets Being Built," Astronautics, no. 27 (October 1933), pp. 1-8; and "Society's Rockets Near Com- pletion," Astronautics, no. 28 (March 1934), pp. 2-6. 12. "Rocket Experiments of 1934," Astronautics, no. 29 (September 1934), pp. 1-3. 10. NUMBER 10 155 13. "The Flight of Rocket No. 4," Astronautics, no. 30 (October-November 1934), pp. 1-4. 14. "Test Report on Rocket No. 3," Astronautics, no. 30 (October-November 1934), pp. 5-6. 15. "December 18, 1941—Reaction Motors, Inc., was organ- ized to continue development of Wyld thrust chamber." This statement was attributed to Lovell Lawrence in letter from H. A. Koch, Reaction Motors Division, Thiokol Chemical Corporation to A. J. Kelley, Aerojet-General Corporation, 7 July 1961, regarding preparation of chronology by George S. fames for American Rocket Society Space Flight Report to the Nation. 16. John Shesta, "Report on Rocket Tests," Astronautics, no. 31 (June 1935), pp. 1-6; and, same issue, p. 12, Nathan Carver, "Flame Data for Test Runs." 17. "Report on Motor Tests of June 2nd," Astronautics, no. 32 (October 1935), pp. 3-4. 18. Alfred Africano, "Report on the Rocket Motor Tests of August 25th," Astronautics, no. 33 (March 1936), pp. 3-5. 19. "Rocket Motor Tests of October 20, 1935," Astronautics, no. 34 (June 1936), p. 5. 20. "ARS No. 2 Proving Stand," Astronautics, no. 40 (April 1938), pp. 15-17. 21. Pendray, "Rocket Tests at Pawling," Astronautics, no. 38 (October 1937), pp. 9-10; and, same issue, pp. 10-12, Africano, "Report on Model Flight Tests." Peter van Dresser, "Dry Fuel Experiences," Astronautics, no. 41 (July 1938), pp. 9-12. Africano, "New Model Stability Tests," Astronautics, no. 44 (November 1939), pp. 1-6; and, same issue, pp. 11-13, Roy Healy, "Model Rockets." Shesta, "Powder Flight Tests," Astronautics, no. 45 (April 1940), p. 3. 22. Robert C. Truax, "Gas, Air, Water," Astronautics, no. 40 (April 1938), pp. 9-11; and, same issue, pp. 1.1-12, James H. Wyld, "Fuel as Coolant." 23. John Shesta, H. Franklin Pierce, and James H. Wyld, "Report on the 1938 Rocket Motor Tests," Astronautics, no. 42 (February 1939), pp. 2-6. 24. Reports on these tests were published in Astronautics, no. 49 (August 1941), as follows: Shesta and Healy, "Report on Motor Tests, pp. 3-5; J. J. Pesqueira and Cedric Giles, "Report on Flame and Sound," pp. 6-7; Cedric Giles, "The Nozzle-less Motor," pp. 8-10, and "Mr. Carver Explains," p. 10. 25. Reports on these tests were published in Astronautics, no. 50 (October 1941), as follows: Healy and Shesta, "Report on Motor Tests of June 22," pp. 3-6; Lovell Lawrence, Jr., "Timing and Ignition Control," p. 6; Africano, "The Afri- cano Motor," p. 7; and Healy, "Wyld Motor Retested," p. 8. 26. See Astronautics, no. 49, p. 7. 27. [Award of REP-Hirsch Prize for 1936], Astronautics, no. 35 (October 1936), p. 17. Africano, "The Design of a Stratosphere Rocket," Journal of the Aeronautical Sciences, vol. 3, June 1936, pp. 287-290. 28. See Astronautics, no. 50, pp. 4-5. 29. See Astronautics, no. 49, p. 10. 30. "Tubular Motors," Astronautics, no. 37 (July 1937), pp. 9-10; and, same issue, p. 11, "Spear Rocket." 31. "The First Rocket Air Mail Flight," Popular Mechanics, vol. 65, no. 5 (May 1936), pp. 641-642. Alexander Klemin, "On the Aerodynamic Principles of the Greenwood Lake Rocket Aeroplane," Astronautics, no. 36 (March 1937), pp. 7-9. [Results of Greenwood Lake Motor Tests; comments by Nathan Carver], Astronautics, no. 38 (October 1937), p. 16. Jesse T. Ellington and Perry F. Zwisler, Rocket Mail Catalog: 1904-1967 (New York, 1967), p. 215. 32. "ARS Membership Votes Merger With IAS," Astronau- tics, vol. 8, no. 1 (January 1963), p. 9. 23. 23. 15 Ludvik OcenaSek: Czech Rocket Experimenter RUDOLPH PESEK AND IVO BUDIL, Czechoslovakia The first Czechoslovak rockets were launched at the end of the 1920s. The largest public demon- stration, of a whole range of rockets, including two- stage ones, was held on 2 March 1930 near Czecho- slovakia's capital city Prague. The rockets, some of which are shown in Figure 1, were about 20 inches in length and one at least reached the re- markable altitude, for that time, of 4,700 feet. They were designed, constructed and tested by the Czech inventor and entrepreneur Ludvik Oce- nasek (1872-1949). This typically self-made man had an unusually wide span of interests, both tech- nical and political, which warrants our interest in his life work. He is shown in Figure 2 with his son, Miroslav, a graduate electrical engineer who worked with his father on one of the latter's projects, a hydrodynamic boat. Born into a poor mining family, Ludvik Oce- nasek taught himself to be a mechanic, and while working at that trade succeeded in completing his education in a middle vocational school. At the age of 22, after working in a patent office, he opened in Prague his own machine shop which in time grew into a medium-sized industrial plant. At first his plant limited itself to electrical appliances, but later proved equally successful in producing a variety of technical developments such as an im- proved bicycle; crystals for radio receivers; a sys- tem of underground loudspeakers that he perfected and produced for stadiums; and eventually new machines for the pharmaceutical industry, and mili- tary weapons. His enterprise did not restrict itself to the mass production of existing products, how- ever; the plant also produced the new inventions Ocenasek had patented. His original workshop, where he developed his first "noiseless" machine- gun, is shown in Figure 3. Creativity marked his entire life, from the merry- go-round he designed and constructed at the age of eight to the new type of recoil device for firearms— for which a patent was awarded to him two days after his death on 10 August 1949. In the first decade of the 20th century, his interest centered on avia- tion. In 1905 Ocenasek designed and built an aero- nautical rotary engine (Figure 4), which was similar to the subsequently famous French Gnome engine. This eight-cylinder radial rotary engine was intro- duced in 1908 at the industrial exposition in Prague. A letter describing it was published in the French review Le Monde Industriel.1 The motor is preserved in Prague's Technical Museum. Another French journal, Encyclopedic Contemporaine2, praised Ocenasek's engine for its light weight and high output. It developed 12 horsepower and weighed only 165 pounds (13.8 lb/hp). Ocenasek of course built his radial rotary air- plane engine because he wanted to fly. In 1910 and 1911 he built a monoplane which ranged among the largest aircraft of its time (see Figure 4). It had a wing span of 39 feet (12 m), an over-all length of 36 feet (11 m), and its propeller diameter was 8i/2 feet (2.6 m). Its "Gnome type" rotary engine de- veloped 50 horsepower. The plane's total loaded weight, with pilot, 75 kilograms of fuel and 8 kilo- grams of lubricant, amounted to approximately 1325 pounds (600 kg). The entire flying machine could be transported in three crates and assembled in two hours. In this plane, through constant improvements, Ocenasek on 30 November 1910 attained a maxi- mum flight distance of not quite 100 feet (30 m). However, when his chief mechanic Serntner, during a test flight in 1911, lost control and the plane burned, Ocenasek was obliged to abandon his ex- 157 158 SMITHSONIAN ANNALS OF FLIGHT FIGURE 1.—Some of the solid propellant rockets developed by Ludvik OcenaSek. pensive experiment in aviation. Meanwhile his firm, transformed into a limited liability stock company, declared bankruptcy. A similar interest by Ocenasek in rocketry and jet-propelled boats marked the decade from 1928 to 1938. These years, just before World War II are also characterized by Ocenasek's efforts to improve the weaponry of the Czechoslovak armed forces. Toward the end of his life he supported himself as a self-employed designer and builder of machinery for the pharmaceutical industry. As late as 1949, when he was 77, he won three prizes for his ap- paratus in this field. Such is the irony of fate, however, that Ludvik Ocenasek gained high recognition in his own coun- try not as an inventor but as a fighter for Czecho- slovak independence. Toward the end of World War I he became a member of the Mafia, which was NUMBER 10 159 FIGURE 2.—Ludvik Ocenasek (1872-1949) and his son Ing. Miroslav Ocenasek (1898-1955). then a secret underground organization of patriots striving for national liberation from the Austro- Hungarian Empire. He detected the existence of a secret telephone line between the Austro-Hungarian and German general staffs, tapped the conversa- tions, and passed the resulting intelligence to the resistance movement. In 1918 he took an active part in organizing the Czechoslovak army. This gained him immense popularity during the 1920s. A small footnote to Ocenasek's life story is that in his old age, during World War II, he again participated actively in the resistance, this time against the Nazis, and under the German occupation was fol- lowed and interrogated by the Gestapo. During the Prague uprising of May 1945, at the age of 73, he fought on the barricades, rifle in hand, and sus- tained serious multiple wounds. The name of Ocenasek did win world fame once in connection with rocketry, early in 1930. This was due to a journalist's hoax. A newspaperman ran a fanciful article in his Christmas (1929) issue to the effect that Ludvik Ocenasek was planning to send his rocket to the moon in 1930 with a crew of nine aboard. The lunar space ship was described as hav- ing six rockets for thrust and two for braking. The news item was picked up and copied by papers in Austria, Denmark, Germany, Italy, the Nether- lands, Poland and Switzerland, Ocenasek took it as the joke for which it was meant. This did not, how- ever, prevent him from receiving several hundred letters from all over Europe, and even from the United States, written by volunteers eager to ac- company him on his trip to the moon. Perhaps one of these would-be moon-trotters, Miss Sally Gallant of New Castle, Pennsylvania, is still alive. Her letter was typical of many American offers: I am five feet four inches tall, weight 138 pounds, am blonde, speak Polish and English. I work as a nurse, I am 20 years old, and would like to fly with you to the moon.3 Of course that newspaper prank did have its kernel of truth—Ocenasek's serious experiments in rocketry. He began them in 1928, inspired by re- ports of successful experiments performed by Dr. Robert H. Goddard, engineer Max Valier, Professor Hermann Oberth and others. He corresponded with Professor Oberth, who at Ocenasek's invitation, came to see him in Prague. The two are shown to- gether in the Czechoslovak capital in Figure 5. In- cidentally, in the same city Ocenasek met with another pioneer of high altitude flights, Professor August Piccard. Ocenasek thoroughly studied Goddard's initial results and similarly concluded that gunpowder was not the ideal propellant for rocket acceleration.4 He planned to use liquid propellants as advocated by both Goddard and Oberth, such as alcohol or hy- drogen and oxygen. His objective however was far less fantastic than a flight to the moon. His aim was to utilize rockets for delivering mail between conti- nents via high altitude trajectories. Fortunately a series of photographs of Ocenasek's 1930 rocket tests have survived, and these are shown in Figure 6. The motion pictures of these public demonstrations on 2 March 1930 constitute a unique document. However, more concrete data is lacking thus far. Ocenasek feared that once again, as in the case of 160 SMITHSONIAN ANNALS OF FLIGHT FIGURE 3.—OcenaSek's workshop and his first noiseless machine gun. FIGURE 4.—a, Ocenasek's aircraft rotary engine of 1908, which produced 12 hp at 600 rpm and weighed 165 lb (75 kg); b, his monoplane of 1910-1911, showing placement of rotary engine; c, control surfaces of the monoplane. NUMBER 10 161 FIGURE 5.—Ludvik OcenaSek and Professor Hermann Oberth in Prague. his radial aircraft engine, he might be deprived of priority in his invention, and, therefore, concealed technical details. Only a single model has survived to the present day. It apparently is a second stage which still contains its unburned propellant charge. Ludvik Ocenasek's daughter has kept it, propellant charge and all, in her household for nearly 40 years. Chemical analysis reveals that the propellant con- sists of ordinary gunpowder loaded in a specially shaped paper container which by its form consti tutes a nozzle. After further experimentation, Ocenasek is said to have devised a ground-launching apparatus to aid in overcoming the obstacles to rapid rocket acceleration. This equipment reportedly proved successful, and was tested by having it catapult a heavy sack of sand straight up into the air. Informa- tion on this device, however, has not yet been verified. Ludvik Ocenasek was obliged to foresake further investigation in the rocket field, owing to the de- pression of the 1930s, which caused him to lose his business enterprise and left him with no funds for such research. However he continued to believe in the feasibility of his idea—the transporting mail from Europe to America by rocket. He was certain it would be developed in the immediate future. In April 1930, The New York Sun carried an article on his activities in which he stated: Indeed, rockets with human crews (to quote the terminology of that time) are not improbable, although in this case many difficult problems concerning the physiological reactions of the human body will arise.s However, Ocenasek did not abandon his attempts to find some practical application of the jet propul- sion principle. Since rocket flights were too fantastic for his time, he tried to adapt the reaction principle to powering a boat for shallow waters. He found support and encouragement in the Bata Shoe Com- pany. The company welcomed a source of cheap motive power for its flat-bottomed river craft which delivered its footwear via the shallow unregulated rivers of central Europe. In 1933 he tested his first hydrodynamic boat (No. 1), a small craft on which the entire four- horsepower power plant was mounted as an auxi- liary power package. These trials proved promising. Streams of water were forced through jet nozzles placed just above the surface of the water in the river (see Figure 7). He subsequently constructed a larger boat (No. 2) weighing 1.4 metric tons to carry six passengers (Figure 7c). With the equipment still relatively unperfected, this craft achieved good results. With a draft of 7 inches (18 cm) it attained speeds of 9 miles per hour (14 kph) and above all displayed considerable towing potential for pulling barges, with unusual maneuverability. In 1935 the Czechoslovak armed forces ordered such a jet-powered boat (No. 3) from Ocenasek, and added it as an operational unit to its Danube River fleet. Under full load, the boat could cruise at 15 miles per hour (24 kph), developed a pull of 1650 pounds (750 kg) and could haul 300 metric tons of freight at 5 miles per hour (8 kph). A publicity film about Ocenasek's hydrodynamic boat was prepared at the time, but we have thus far been unable to find a copy. Latest reports suggest it may have been sent to Amsterdam. Further orders for boats came in. Ocenasek's son assembled four such boats in Poland; interest was expressed by Japan, Rumania, and the Netherlands. There exists a project design for a very large pas- senger-carrying river craft. But World War II and the occupation of Czechoslovakia in 1939 put an end to all of Ocenasek's activities in this direction. Thus, his most outstanding technical achievement never was able to realize its potential. In the years just before World War II, however, Ocenasek had turned again to the technology of military weapons, out of a desire to improve the arsenal of Czechoslovakia's Army. And once again he worked with rockets. If we know little of his first generation of rockets, of the latter military ones we knew even less. Ludvik Ocenasek performed these experiments secretly in an unknown rock 162 SMITHSONIAN ANNALS OF FLIGHT NUMBER 10 163 FICURE 6.—a, Launching site and rack used during a demonstration of OcenaSek's solid propellant rockets on White Mountain, near Prague, 2 March 1930; b, OdenaSek preparing rocket for launch; c, demonstration rocket being placed in rack; d, larger rack used for some rockets; e, OcenaSek inspecting rocket prior to launch; /, two-stage rocket, being placed in launcher; g, successful launch from larger rack; h, explosion of rocket during take-off; i, OcenaSek and his son inspecting rockets following tests; /, Miroslav OCen&Sek and co-worker inspecting damage to fins and nozzle of demonstra- tion rocket following test. 164 SMITHSONIAN ANNALS OF FLIGHT FIGURE 7.—a, Ocenasek's water-jet propelled boat No. 1, showing exhaust nozzles; b, rear of boat No. 1; c, water- jet propelled boat No. 2; d, boat No. 3 during demonstra- tion test; e, water exhaust ducts of boat No. 3. NUMBER 10 165 w quarry near Prague. Even his family learned of this activity only by chance, when he come home one day injured. Naturally, since that work involved military secrecy no photographs of the actual de- vices have been found. All we have located is a photograph (Figure 8) of two models of these rockets. The projectiles were streamlined and pro- vided with fins. At their rear was located a metal cartridge for the solid propellant. These rockets, moreover, were launched by being fired from a gun. Thus they were really a combination of projectile and rocket, a grenade-rocket similar to the British infantry anti-tank grenade rocket (PIAT) of World War II. The projectile, according to confirmed re- ports, had a range of 1.6 miles (2.5 km) with little dispersion. Ocenasek wanted to share the designs for this new weapon with Czechoslovakia's foreign allies. In this he was unsuccessful, and the plans remained all through the war sealed up in the house where he lived. He died on 10 August 1949 and his son died six years later, on 3 August 1955. His tombstone at the Olsary Cemetery is shown in Figure 9. (Professor Pesek's presentation concluded with a motion picture film showing the 2 March 1930 pub- lic demonstration of Ludvik Ocenasek's first-gener- ation rockets at the White Mountain near Prague.) wgm RS ,nfl BR0D5Kfl FIGURE 9.—OcenaSek's grave in the Olsary cemetery in Prague. FIGURE 8.—Two models of Ocenasek's grenade rocket. NOTES 1. M. Guerin, "Nouveau moteur a explosion et lampe a arc-systeme L. OcenaSek," Le Monde Industriel, 13th year, 31 December 1908, pp. 438-39. 2. Louis Davia, "Exposition jubilaire de Prague," Encyclo- pedic Contemporaine, 1908, p. 204. 3. Theodor Prochazka, "Seek to Go on Flight to Moon; Five Men and a Girl in U.S. Write to Inventor; Take Joke Story Seriously," The New York Sun, 20 March 1930, p. 24. 4. Goddard, "A Method of Reaching Extreme Altitudes," Smithsonian Miscellaneous Collections, vol. 71, no. 2, Decem- ber 1919, pp. 67-68. 5. Theodor Prochazka, "Mail by Rocket Is Latest Plan; Czech Inventor Working on Device to Cross Ocean; Confi- dent He Will Succeed," The New York Sun, April 1930. See also "News From Abroad," Bulletin of the American Inter- planetary Society, no. 1 (June 1930), p. 4. 1. 1. 16 Early Experiments with Ramjet Engines in Flight Yu. A. POBEDONOSTSEV, Soviet Union . . . currently the application of ramjets for space vehicles can be seen in their use for accelerating a rocket xvithin the limits of a continuous atmosphere up to a velocity of mach 7-10. Academician B. S. Stechkin Development of space rockets represents an ex- tremely complex scientific problem. But among the many problems, solution of which determines prog- ress in rocketry, that of the energy content of the propellant heads the list. It can be said with good reason that the launching of sputniks, rocket flight to the Moon, Venus and Mars, manned orbital flights, and soft landing on the Moon—all these remarkable achievements are the gigantic strides in the development of Soviet science and rocket- power engineering. It is quite evident that the de- velopment and modification of jet engines and the selection of the most efficient propellants for them is still going to be one of the fundamental determi- native tasks of cosmonautics for many decades to come, as it was at the very outset of the cosmic era. Conducting research of energy content of propel- lants on a wide scale, Soviet scientists from the very beginning advanced and developed the concept of using air-breathing engines in space engineering in addition to other types of rocket engines. At the beginning of this century K.E. Tsiolkovskiy put forward the concept of using engines propelled by air oxygen for the boost of spacecrafts during their flight in the atmosphere.1 FA. Tsander, as well as other scientists, has de- voted much of his effort to the investigation of this problem.2 The concept of using air-breathing engines to boost space rockets is universally recognized at the present time. Numerous theoretical and experi- mental studies published in the world press indicate that the use of air-breathing engines in the first stages of carrier rockets permits a severalfold in- crease of the mass of sputniks to be orbited, while maintaining unchanged the launching weight, or even decreasing it appreciably, yet maintaining the payload weight. In 1907-13 Rene Lorin, a French engineer, sug- gested the concept of a ramjet engine.3 Its first theo- retical foundation, the design and experiments with ramjet engines, however, were carried out much later by Soviet scientists. One of the closest disciples and followers of N.Ye. Zhukovskiy, Boris Sergeyevitch Stechkin, now Aca- demician, delivering a course of lectures on hydro- dynamics at the Mechanics Department of the Moscow N. E. Bauman Higher Technical School in 1928 expounded his new theory of ramjet engines. Strictly following the classical principles of gas dynamics, he derived for the most general case the equation for thrust and efficiency of ramjet engines in a resilient medium. The problem of the reactive force of fluid flow, passing through a jet engine (for an incompres- sible fluid, when there is no thermal aspect) was developed in detail earlier by N.Ye. Zhukovskiy and expounded in his classic works On Reaction of Fluid Inflow and Outflow and Contribution to the Theory of Ships Propelled by the Reactive Force of Water. B.S. Stechkin investigated in a similar way the 167 168 SMITHSONIAN ANNALS OF FLIGHT resilient medium flow for the first time. Moreover he showed how the efficiency of a ramjet engine could be determined if the external energy was partially or fully supplied to the air, and he investigated the case of air flow compression due to the loss of free stream momentum, as was suggested by Rene Lorin in his time. In this case the air characteristics are changed according to the "Brayton cycle" and its thermal efficiency will equal the difference between unity and the ratio of air temperature at the com- pletion of compression to its initial value at the inlet to the engine. Rumors about this lecture quickly spread among the advanced scientific and technical circles at that time interested in rocketry, and B.S. Stechkin was asked to deliver the lecture once more for a wider audience. Soon such a lecture was held at one of the public lecture halls of the Soviet Army House. The hall was overcrowded and many of those who wished to be present failed to get in. Then Boris Sergeyevitch was asked to publish the lecture. With the aid of his students and disciples Stechkin prepared the lecture for publication as the article "Theory of a Ramjet Engine," first published in February 1929, thus becoming known not only to specialists in the USSR but in other countries as well.4 In this article the equations of ramjet engine thrust and efficiency were given for the first time. Soon after the publication of Stechkin's work, reviews, comments, and references to it, as well as unanimous recognition of USSR priority in this field, began to appear in the technical literature abroad. For instance, the famous Italian scientist Arturo Giovanni Crocco in his monograph "Super- aviation and Hyperaviation," published in 1931, wrote that "the classic theory of ramjet engines had been formulated for the first time in the USSR by the Moscow professor Stechkin." 5 The theory worked out by B.S. Stechkin opened the way for practical works in developing ramjet engines. In autumn 1931 in the USSR a group of ardent enthusiasts and advocates of rocket engineering was set up as a voluntary society which afterwards was named the Group for Study of Jet Propulsion (GIRD). Mainly they were young students and aviation specialists who set for their task the prac- tical development of jet vehicles. GIRD conducted its work in teams while general guidance was ef- fected by the Technical Council composed of the most qualified specialists. Sergei Pavlovitch Koro- lyev, who afterwards became an Academican and a spacecraft designer, was Chairman of the Technical Council. One of GIRD's team, headed by myself, was en- trusted with investigations and experimental test- ing of ramjet engine performance. At the beginning we devoted several months to theoretical calcula- tions and research into possible fields of such en- gines application. Then the time was ripe to com- mence the practical work, i.e., investigations of models and separate units of ramjet engines. Test stand IU-1 was constructed in GIRD by March 1933. It comprised a high-pressure compres- sion station, a battery of tanks accumulating the air compressed up to 200 kg/cm2 and a stop valve measuring the air supply from the gas pressure tanks to the receiver. The latter damped the pres- sure fluctuations of the air supplied to the experi- mental engine. The design of the test stand, pre- served among other papers of that time, is shown in Figure 1, and the ramjet engine model being tested is shown in Figure 2. Air entered the model at various preset values of excess pressure which simulated the dynamic pressure in the inlet diffuser of the engine. Experimental laboratories as well as workshops and design rooms of GIRD were housed at that time in the basement of an apartment building. The first test of IU-1 was carried out on 26 March -fe^fe^^J t -120 iX vMM//A>//,V//w})//, ( Hydrogen tank J=* ( Compressed air }=M —x T ( > —a: x- FIGURE 1.—Diagram of IU-1 facility for ramjet engine testing (from GIRD archives). J^ NUMBER 10 169 FIGURE 2.—Experimental ramjet engine. 1933. The test records of this new field of engineer- ing, i.e., engineering of ramjet engines, have been preserved to this day.6 Record No. 1 briefly stated: At 2:30 a.m. the knife switch of the facility electric motor was activated. . . The compressor was stopped at 2:45 a.m. . . . After 15 minutes had elapsed pressure in the final compression stage had reached 190 atm. Owing to the participation and support of the whole personnel of GIRD the testing and the final adjustment of the facility successfully advanced and after six tests it was fully prepared for the in- vestigation of the ramjet engine model. Figure 3 shows the ignition of various com- bustible air-fuel mixtures and their rates of com- bustion. It was decided to carry on the experiments on ramjet engine models in the IU-1 test stand with gaseous hydrogen, the most available and con- venient from the point of operation, which when mixed with air is ignited in a very wide range and ensures the highest rate of combustion. In the early morning of 15 April 1933 the first test of the ramjet engine model was conducted. It lasted 5 minutes. The conclusion of the test results stated: "The first starting of the engine has proved the theoretical suppositions about jet engines pro- pelled by a gaseous propellant." The test marked the beginning of experimental research on ramjet engines. Four days after the first test the second one was carried out on the IU-1 stand. This time the engine was tested at pressures in the combustion chamber varying from 1 to 3.2 atm. During the test period the engine was started 3 times and it was established that "under normal engine performance the igni- tion of hydrogen-air mixture should be done only once, on starting the engine. The combustion cham- ber having been heated, the ignition may be cut off and the power is adjusted only by means of air and propellant supply." As the work of testing the ramjet engine models proceeded, the methods of investigation were grad- ually modified. From 9 June 1933, the thrust de- veloped by the engine under the test was measured during experiments on the IU-1 test stand. To make the ramjet engine effective not only at supersonic velocities but at subsonic ones as well, designs of ramjet engines were researched in which the air, in addition to being compressed in the dif- fuser due to the air flow kinetic energy, was also compressed by means of certain devices. One of such design was the pulse-jet engine (PuVRD), with the valve at the entry (the prototype jet engine of a pilotless "flying bomb" known later in Germany as the V-l). To investigate the possibility of developing the pulse-jet engine in GIRD, in June 1933 an experi- mental combustion chamber with a valve labelled EK-3, was constructed. The test of pulse-jet engines in 1933 in GIRD permitted a determination of the main problem occurring when developing the design of engines of such type, and an estimate of the volume and difficulties of their solution. It was decided for the 170 SMITHSONIAN ANNALS OF FLIGHT Ignition limits of combustible mixtures I Gases % gas (by vol) in mixture 10 30 SO 70 90 Spec, wt. Acetylene fy "2 V73 Hydrogen H% 0.09 Carbon dioxide CO 1.25 Water (blue) gas C0*H2 Hydrogen sulfide H%S Ethylene fy^ f.ZS Dithiane C% Hi Ethane Z% Hs r.357 Methane jjf^ . 0.7t7 Ammonia NH3 0.7ft Butylene ^H2 ■ Propylene Cj Hg ■ Pentane tjH^ ■■ Propane fyHj ■ 2.02 Butane Ct, Hfo ■i II Vapors Carbon bisulfide C$i Ethyl ether Ci,H^0 Methyl alcohol CH<,0 Ethyl alcohol fyfyfl Acetone CjHjO Oil m Benzene C5H5 m Toluole CjHg m j a FIGURE 3.—Parameters of fuel-air mixtures used in tests: a, Ignition limits of com- bustible mixtures; b, burning rate of mix- ture versus combustible gas content. V(cm/sec) \«Z — too fO *h m —Ci H? - l»Z"Z 700 J&HJ/CnyHj too . CO 0 10a 20 HO 50 % ga3 (ty vol) immediate years to direct all efforts toward research on ramjet engines. Experimental works on investigating the ramjet engines, from April 1933 in GIRD, were conducted for the whole year without interruption. Success of the first investigations made it possible to com- mence the construction and testing of a ramjet engine in free flight. A bold idea discussed and ap- proved by the GIRD Technical Council was to arrange for the engine to be tested in the body of an artillery projectile and to test ramjet engines at supersonic velocities, i.e., in the region where the ramjet engines are the most efficient. It was neces- sary to prove experimentally the feasibility of de- veloping a ramjet engine—an engine which at that time had been built nowhere in the world—and also to prove in practice the correctness of theo- retical statements, i.e., to prove in principle that an engine of such a type is capable of developing thrust. At that time, when the question was still being raised as to whether it was advisable to work on developing ramjet engines at all, an answer could only be given by an actually operating ramjet en- gine having shown its working ability in flight. Selection of the propellant for such a ramjet engine model was of great significance. As a result of a thorough investigation of all conditions of a ramjet engine performance during the forthcoming tests, the following requirements were suggested for the propellant: (1) it should be solid; (2) it should be inflammable and should have a high combustion rate in a wide range of air mixtures; and (3) it should have calorific capacity per liter as high as possible. Having investigated a number of propel- lants we decided to choose white phosphorus as the one most convenient for the purpose (see figure 4). NUMBER 10 171 heat content (cal/1) 10000 - 8000 Cast magnesium Gasoline, kerosene •Benzine 6000 Lithium [Al2] powder o°c ^.^£20°C ^50°C Phosphorus Ethylene 4000 2000 0 blue gas oil gas Methane lighting gas hydrogen 200 400 600. P(abs atm") FIGURE 4.—Calorific content per liter of fuel at various pressures. As the work procedure has shown, our choice of propellant was a good one. At the same time, we also decided to use "solid benzene" as a propellant. Therefore the ramjet engine intended for the oper- ation on an artillery projectiles was designed with due regard to the possibility of using both phos- phorus and benzene. To prepare a ramjet engine model for free flight testing, a special mobile test stand was constructed in which the rotating combustion chamber of a jet engine was installed and on 12 July 1933, at one of the proving grounds near Moscow, the first test of the phosphorus-operated combustion chamber in the rotating ramjet engine was carried out. The aim of the first test was to investigate the properties of phosphorus as a propellant for a jet engine, and in particular for an engine installed on an artillery projectile. The whole second half of 1933 was devoted to the preparation of the ramjet engine to the flight tests. Owing to the harmonious and cohesive work of a small group of the third team of GIRD, all the bench tests and preparatory work that had been set by the program to pave the way for the beginning of flight tests were effected in a short period of time, and in autumn 1933 the ramjet engines were given their first flight tests. The ramjet engine models had the contour of a long-range shell of a 76-mm (3-in.) cannon (Figure 5). The internal part of a ramjet engine comprised an entry channel, a combustion chamber and a noz- zle. The propellant grain was placed directly in the combustion chamber. In order to prevent the pene- tration of combustion gases into the internal cavity of the engine, the exit nozzle was plugged with a metal stopper (part 4 in Figure 6) prior to firing the cannon. After the ramjet engine had cleared the cannon channel, the plug would detach from the projectile and fall near the cannon. Direction of flight a FIGURE 5.—Ramjet engine under study: a, Plan view; b, de- sign; c, rear part of missile, with plug. 1, ogival part (nose) 5, nozzle 2, fuel cap 6, cavity for payload 3, shell body 7, intake channel 4, plug 8, air inlet 1, 172 SMITHSONIAN ANNALS OF FLIGHT The first version of the projectile with a ramjet engine was provided with an empty cavity for hous- ing the pay load (see 6 in Figure 5). The propellant grain was a metal frame filled with white phosphorus (2 in Figure 6). Inside the grain, along its axis, was a conical cavity positioned with its wide end towards the exit nozzle. In order to prevent the propellant grain from premature self- ignition during the transportation and preparation for model testing, the phosphorus grains were coated on all sides with a thin layer of varnish. The longitudinal ribs of the metal frame of the grain were manufactured of 2-mm-thick sheet steel and the transverse plates were of electron, a magnesium alloy. It was understood that the electron plates would burn together with phosphorus and thus con- siderably increase the total calorific capacity of the grain. For the first tests, 10 projectiles with ramjet en- gines were prepared. They were fired from the 76- mm cannon of 1902 pattern at 20° angle of eleva- tion. The speed of the projectile as it left the barrel of the cannon was 588 m/sec. Prior to firing the projectiles with ramjet engines two shots were fired with a modernized shrapnel- filled shell, which fell at a distance of 7200 m. Then projectile No. 1 was fired without propellant. In- stead of a phosphorus grain the frame of the grain filled with sand of the same weight was fitted in its chamber. The flight of this projectile was accom- panied by strong whistling. Its flight range was roughly estimated at 2000-3000 m, since the point 1 ~~ Z J FIGURE 6.—Combustion elements of ramjet engines developed by GIRD. 1, ogival part (nose) 3, shell body 2, fuel charge 4, plug of impact could not be determined because all the observers had been positioned further down range. Then 9 shots were fired with ramjet engines, with results as shown in Table 1. TABLE 1.—Results of first test Test d, dB dCr dcr/dt 1 fit Range no. (mm ) (mm) (mm) (*g) (H) (m) 0" — — — — 6.30 — 7200 1" 28 28 32.0 1.140 6.17 — 2000 2 30 28 32.0 1.070 6.13 0.380 5300 3 30 28 34.5 1.150 6.18 0.340 8000 4 25 25 29.0 1.160 6.20 0.400 5350 5 30 25 31.0 1.030 6.22 0.390 4900 6 28 25 32.0 1.140 6.35 0.390 5300 7 30 25 34.0 1.135 6.25 0.415 6000 8 30 28 32.0 1.070 6.23 0.390 4500 9 25 25 28.0 1.120 6.30 0.415 3200 10 30 28 32.0 1.070 6.06 0.430 6000 a Modernized shrapnel-filled shell. b Without fuel. Data from these first tests confirmed the possi- bility of using the artillery cannon for catapulting ramjet engines, and the experiment proved the absolute safety of firing projectiles of the adopted design. In all cases the ignition of propellant in the chamber of the ramjet engine did not fail, the propellant having ignited 10-15 m away from the cannon. The first tests of ramjet engines in flight, carried out in September 1933, proved that an engine of such a type was capable of operation. The increase in flight range of the projectile with a ramjet en- gine (projectile no. 3) of almost 1 km compared to that of a standard projectile is the most convincing evidence of this fact. The increase was obtained in spite of the fact that, from an aerodynamic point of view, a projectile with a through bore is much less efficient than a conventional one and, therefore, at that part of flight trajectory where the engine was out of operation the projectile with a ramjet engine experienced higher drag than a standard projectile. In all cases the projectiles with operating ramjet engines flew further than a projectile of the same weight and shape but without propellant. Thus, the only explanation of the flight range in- crease can be the fact that the ramjet engine de- veloped some positive thrust during the flight. This fact was of a great fundamental significance. The results of these flight tests of artillery projec- tiles with ramjet engines made it possible not only NUMBER 10 173 to establish the fact of positive performance of a ramjet engine, but also to determine the amount of thrust developed. Based on the preliminary calcu- lations, the values were defined for drag experienced by the projectile body and for thrust developed by a ramjet engine. When the flight velocity with which the shell escaped the cannon barrel was 588 m/sec, the calculated drag was 20 kg and the ram- jet engine thrust equalled 18 kg; i.e., it was some- what less than the drag (Figure 7). Therefore, the engine was able to compensate 90% of the drag, but was not able to overcome it completely or to impart positive boost to the projectile. As the projectile drag exceeded the engine thrust, its velocity should decrease as the flight proceeded. The decrease of velocity caused even greater difference between the drag and the thrust. Thus, as at the moment of escaping the cannon, at the initial velocity stated, so in further flight the designed thrust of ramjet engines was less than the drag. This did not in any way confuse us, as the results of flight tests, even with such a thrust-drag ratio, enabled us to establish the fact of the ramjet engine operation and to deter- mine the degrees to which the thrust obtained in practice approximated that designed. Processing the flight-test data showed that the actual drag in fact exceeded that calculated and the actual thrust was somewhat below that designed. It could be explained by a number of causes, such as deformation of the metal frame of the phos- phorus grain, inadequate flight stability of pro- jectiles with ramjet engines, and so on. kg 80 60 HO 20 Disclosure of the causes for the decrease in thrust, - r fc ^ V* A\ V iJ 0 200 WO BOD S00 fOOO v(m/sec) FIGURE 7.—Air drag versus thrust developed by ramjet engine. compared with the designed value, and the increase in drag was a valuable result of the first set of ex- periments. As soon as the causes of the deficiency in ramjet engine performance were known, it be- came possible to look for methods to eliminate them and to modify the engine. After the first set of experiments the second set of flight tests on ramjet engines were carried out in February 1934 and the third, in 1935. Six additional models of ramjet engines were designed for these tests, which were positioned in the body of a 76-mm projectile. Some versions of ramjet engines comprise several groups differing in the size of diffuser entry section or nozzle throat, and some test models of projectiles with ramjet engines differed in the amount of propellant used. The second version of projectiles with ramjet en- gine differed from the first one only in the design of the phosphorus-grain frame. To decrease the distor- tion of the longitudinal ribs of the frame it was decided to make it possible for the grain to rotate freely in the chamber. With such a design, the rise of the grain angular velocity occurred not instantly, but gradually, thus preventing distortion of the grain ribs. Owing to the modifications of the jet engine design, the results of the test were appre- ciably better. To prevent fuel loss, the grain framework of the third version of the engine was made so as to de- crease the ejection of bits of phosphorus, and phos- phorus with lower melting temperature was used. Due to this modification of the propellant grain, the value of specific impulse in the engines of the third version increased to 423 kg sec/kg of propellant. In these engines the propellant grain framework was intended to retain phosphorus during the pe- riod of the projectile boost inside the cannon, and then it was used as a propellant. That is why the test of this group of projectiles was quite significant. Up to that time, the interesting concepts of FA. Tsander and Yu.V. Kondratyuk, of using metal propellant in jet engines, were developed only theoretically or by means of experimental testing under bench conditions. Ramjet engines designed by the GIRD third team were the first jet engines in the world operated in flight using metal propel- lant not in the form of powder but as an element of structure. During these tests the projectiles with ramjet en- gine covered a distance of 12 km (Table 2). 174 SMITHSONIAN ANNALS OF FLIGHT TABLE 2.—Results of flight tests on air-breathing jet engines of versions 2,3, 4,5, and 6 Version d, (mm) dCr (mm) der/df q (kg) q< (kg) w„ (m/sec) Range (m) P No. Shots Diagram of jet engine 28 28 28 28 34 35 36 37 1.22 1.25 1.29 1.32 5.600 5.600 5.600 5.600 0.300 0.300 O.300 0.300 600 600 600 600 8500 10000 9500 9500 185 320 300 300 5 5 5 5 2 3 28 30 35 35 1.25 1.17 6.200 6.200 0.277 0.270 680 680 10700 10500 423 400 10 10 Second version, stabilized phosphorus cap Electron metal shell 30 35 1.17 6.095 0.645 680 12500 346 3 4 .. n 30 35 1.17 5.850 0.400 680 11807 364 4 30 35 1.17 5.925 0.580 680 12021 334 6 30 35 1.17 5.662 0.620 680 12100 396 5 30 35 1.17 5.867 0.620 680 10600 330 5 During the test quite high efficiency was ob- tained. Its value in the best experiments was as high as 16 percent, and taking into account that a large part of propellant was exhausted from the engine at the initial moment of the projectile flight in the air, the actual efficiency was considerably higher. Figure 8 displays the dependence of the flight range of the projectile with a ramjet engine (which was obtained from th