Considérations sur les Résultats d’un Allègement indéfini des Moteurs.

Tours: Deslin Frères, 1913.

First edition, exceptionally rare separately-paginated offprint, inscribed by Esnault-Pelterie, of the published version of his lecture, delivered in 1912 in both St. Petersburg and Paris, which first demonstrated theoretically that space travel was possible; it marks the beginning of theoretical astronautics. “The lecture contains all the theoretical bases of self-propulsion, destroying the myth that rockets need atmospheric support and giving the real equation of motion. Anticipated is the use of auxiliary propulsion for guidance and complete maneuverability of rockets. Also contained are calculations of the escape velocity, the phases of a round-trip voyage 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 . . . This 1912 lecture is the first purely scientific study marking the birth of astronautics. While Tsiolkovsky had the prescience and talent to first suggest, in 1903, rocket propulsion to space, REP [as Esnault-Pelterie liked to be called] was the first to develop the equations of the problem and to establish the mathematical theory of interplanetary flight. REP is thus the founder of theoretical astronautics” (Blosset, p. 9). As far as we can determine, no other copy of this offprint has appeared on the market; OCLC lists Bibliothèque Nationale only.

Provenance: Boldly inscribed and signed by Esnault-Pelterie on front wrapper: “En souvenir affectueux des premiers balbutiements … que dis-je ? des premiers tressaillements d’un art aviatique en gestation!” (“In affectionate memory of the first faltering steps … how do I put it? the first quickening of an aviation art in gestation!”).

Born eleven months before American rocketry pioneer Robert Goddard, Esnault-Pelterie (1881-1957), French inventor and engineer, made substantial contributions to both aeronautics and astronautics, the design and flying of planes and the design of rockets. REP graduated in engineering at the Sorbonne, and was the fourth man in France to obtain a pilot’s license. He made a series of remarkable contributions to the development of airplanes: he built his first powered aircraft in 1907, the REP 1, which used ailerons rather than wing-warping to steer, had internally stressed wings instead of the external wire struts of the Wright brothers, and utilized a fuselage with an aluminium frame rather than wood. A serious crash in 1908 ended Esnault-Pelterie’s flying career, and although he persisted in building REP aircraft through the First World War, after his crash he turned to thinking about the possibility of space travel. “‘When flying became a fact,’ he wrote later, ‘having once been only a dream, it was apparent to me, as one who remembered the time when there were even no automobiles, that it would develop rapidly, and I wondered what the next stage might be. Once the atmosphere had been conquered, there remained nothing more but to strike out into the empty space of the universe’” (French & Burgess, p. 54).

“In the public mind in the beginning of the 20th century, rocketry and space exploration belonged more to the realm of science fiction than to the field of ‘serious’ research pursuit … It was at this time that isolated visionaries and thinkers, including amateurs, sketched the sinews of the spaceflight concept. Technical details of rocketry and space travel had precarious credibility. Consequently, usual all-knowing intellectuals of the day dismissed them as ridiculous. The word astronautics did not yet exist. Actually, science fiction literature had used the word astronaut by that time, but astronautics was unknown as a term of science and engineering … Esnault-Pelterie’s credibility of an accomplished engineer and fame as an aviation pioneer helped him to gain acceptance by mainstream scientific audiences” (Gruntman, pp. 1-2). By 1912 France had become the leading nation in aviation progress, and Esnault-Pelterie was a star, surpassed only by Bleriot and the Wright brothers in terms of notoriety and fame.

The results of Esnault-Pelterie’s deliberations were first presented in his lecture, delivered on 14 February 1912 in St. Petersburg as a guest of the Imperial All-Russian Aerial Club, and then again in Paris on 15 November 1912 to the French Physical Society. His lecture celebrated “‘the Rocket’ as the sole machine capable of realizing fiction’s dream of ‘traveling from planet to planet’. A series of impressive mathematical formulas and planetary trajectories confirmed the propellant forces necessary to accelerate the rocket beyond Earth’s gravity: an escape velocity of just over eleven kilometres per second, what he called the ‘critical velocity of liberation’, enough to take human beings ‘to infinity’. His conclusion: only atomic power (radium) would suffice to provide the propulsive force for such extreme velocities. Esnault-Pelterie also considered the physiological effects of spaceflight, artificial atmospheres and zero-gravity, and heat and energy sources from the sun. None of these challenges were insurmountable. His itinerary was bold: the Moon, Mars and on to Venus. Humanity was destined, in his concluding words, to become a new ‘Halley’s comet’, to reach its fantastic velocities into interplanetary space” (Smith, p. 82) 

“Esnault-Pelterie emphasized the importance of addressing physical foundations of spaceflight:

‘Numerous authors made a man traveling from star to star a subject for fiction … No one has ever thought to seek the physical requirements and the orders of magnitude of the relevant phenomena necessary for realization of this idea … This is the only aim of the present study’ [the present offprint, p. 3].

“In his lecture, Esnault-Pelterie discussed the acceleration of a rocket and derived the rocket equation. He considered the energetic properties of guncotton, hydrogen-oxygen mixture, and radium as propellants. Then he provided estimates of the required velocity increments and flight times for travel to the Moon, Venus, and Mars and requirements to the propellant for such missions. Considering interplanetary flight of humans, Esnault-Pelterie proposed passive spacecraft temperature control,

‘… a vehicle built in such a way that one half of its surface would be of polished metal … The other half of the surface … would be … a black surface. If the polished surface turns to the sun, the temperature would decrease. In the opposite position, the temperature would increase’ [p. 13]” (Gruntman, pp. 2-4).

Esnault-Pelterie’s lecture first appeared in print in the Journal de Physique théorique et appliqué, but in abridged form, due to both space considerations and the trepidations of the Journal’s editor, who was shocked by Esnault-Pelterie’s ideas on space travel. “REP deplored the exaggerated condensation of the lecture, which was the cause for an apparent divergence between Goddard’s and his own opinions concerning the possibility at the time of building 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. 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” (Blosset).

It is unclear how much Esnault-Pelterie was influenced by Tsiolkovsky. “The use of rockets for space travel had been discussed by the Russian scientist Konstantin Tsiolkovsky in his Exploration of Cosmic Space by Means of Reactive Devices (1903, 1911-12). “Tsiolkovsky had grasped the principle of reaction flight as early as 1883, and his 'Exploration of Space Using Reactive Devices' contained the first mathematical exposition of the reaction principle operating in space. In ‘Issledovanie mirovykh prostranstv reaktivnymi priborami’ . . . Tsiolkovsky set forth his theory of the motion of rockets, established the possibility of space travel by means of rockets, and adduced the fundamental flight formulas” (DSB).

“Tsiolkovsky’s work was published only in Russian, and remained little known to Western scientists until the 1920s. Whether Esnault-Pelterie knew of Tsiolkovsky's work before he wrote his 1913 paper is unclear. However, considering that he had published little up to this time, one wonders how he would have been invited to speak in Russia if he had not been in communication on these topics with people in Russia before this date. This leaves open the possibility that he may have had access to Tsiolkovsky’s work in some form prior writing his paper. REP did not refer to Tsiolkovsky’s work in his 1913 paper – at least not in the abridged form it which it was published – but at the very minimum he must have been informed of Tsiolkovsky’s work during his trip to Russia, as by this time Tsiolkovsky’s paper had been published twice in Russian. What sort of reception his speech received seems also to be unknown. In his L’Astronautique (1930), Esnault-Pelterie mentioned that his 1912 speech was never published in Russia. He also acknowledged Tsiolkovsky’s contributions in print for the first time when he mentioned Tsiolkovsky’s papers in the historical introduction of his L’Astronautique (1930)” (

Esnault-Pelterie’s paper was far ahead of its time, and it failed to stir the public interest, in contrast to the way that Goddard’s 1919 publication A Method of Reaching Extreme Altitudes did, perhaps because of its obscure title, or perhaps because it was not backed up by an institution like the Smithsonian, as Goddard’s was. Esnault-Pelterie’s conclusions did, however, have a significant influence on other rocketry pioneers. “Robert H. Goddard, America’s future rocket scientist, probably read them in the summer or fall of 1913 as he was convalescing from tuberculosis in his Worcester, Massachusetts, home. True enough, Goddard had been thinking of rocket motors and spaceflight for some years, as attested by his notebooks from 1908-9 and by his experimental work at Princeton University in 1912-13. But Esnault-Pelterie’s 1912 paper was very likely the catalyst that spurred Goddard to present his work publicly as a patent, through lectures, and in published form. From Italy too, the young military and aviation engineer Giulio Constanzi drew from Esnault-Pelterie’s work to postulate the new science of exhaust velocities and mass ratios for an accelerating rocket …

“For some Russians Esnault-Pelterie remained a focus of interest, the true pioneer. His rocket calculations set a standard. The French would soon chart a journey from Earth to Mars, wrote K. E. Veigelin, while we Russians were still making our way ‘from Petersburg to Moscow’. It was the French, wrote N. Tolstoi, who were allowing humanity to ‘step over the boundaries’ between fantasy and reality with their project for a navigable ‘spacecraft’ … All that interplanetary travel needed was to apply the sciences of physics and orbital mechanics to the task, in the manner of Esnault-Pelterie” (Smith, pp. 82-83). Tsiolkovsky responded to these claims by publishing as a separate pamphlet in 1914 his Issledovanie mirovykh prostrantsv’ reaktivnymi priborami, a completion and expansion of his earlier journal publications with the same title.

Esnault-Pelterie continued to think about astronautics after the First World War, and entered into correspondence with Goddard and the German rocketry pioneer Hermann Oberth. On 8 June 1927, Esnault-Pelterie delivered a lecture ‘L’Exploration par fusées de la très haute atmosphère et la possibilité des voyages interplanétaires’ to the Société Astronomique de France. He began by emphasizing the connections to his groundbreaking presentation fifteen years earlier:

‘Mr President, Ladies, Gentlemen. Our [Society] President, General Gustav Ferrié, on the suggestion of our colleague Mr André Hirsch, asked me several times to present, with more details, to our Society the lecture that I had given on 15 November 1912 to the French Physical Society’

(translation from Gruntman, p. 4). This time his lecture aroused great interest, and in 1928 the French Astronomical Society published an expanded version of it both in its Bulletin and as a separate book. It was on page 64 of this book that the word ‘astronautics’ first appeared in print. With its publication, the French Astronomical Society provided legitimacy to the new field of astronautics. In 1930, Esnault-Pelterie published L’Astronautique, the first real textbook on the subject. He then devoted himself to the study of rocket motors with some support from the military authorities. This activity was interrupted following the German invasion of France at the beginning of the Second World War.

Esnault-Pelterie is credited with a great number of significant astronautical inventions. In addition to inventing the aileron and the pilot’s joystick, he is said to have pioneered the idea of inertial navigation, to have been the first to devise the gimbal-mounted rocket engine, and to have come up with the concept of aero-braking to slow spacecraft down for planetary landings. But the French rocket movement paled in comparison to that of the Germans before and during the Second World War, and Esnault-Pelterie never got the opportunities that came the way of rocket designers such as Werner von Braun. France honoured Esnault-Pelterie with a postage stamp in 1967, ten years after his death. He was inducted into the International Space Hall of Fame in 1976. 

Blosset, “Robert Esnault-Pelterie: Space pioneer,” in Durant & James, First Steps toward Space (Washington DC: Smithsonian Institution Press, 1974), pp. 5-31 (pp. 23-31 contain an English translation of the unabridged lecture). French & Burgess, Into That Silent Sea: Trailblazers of the Space Era, 1961-1965, 2007. Gruntman, From Astronautics to Cosmonautics, 2007. Norman 713. Smith, Rockets and Revolution: A Cultural History of Early Spaceflight, 2014. Von Braun & Ordway, History of Rocketry & Space Travel, 1975 (see pp. 74-75).

Offprint from: Journal de Physique théorique et appliqué, Cinquième Série, Tome III, March 1913. 8vo, pp. 15 (journal pagination 218-230). Original printed wrappers, some fraying and wear to extremeties. A very good copy without any restoration.

Item #4728

Price: $12,500.00