Rocketry
He became interested in space travel, and, not knowing of Tsiolkovsky's 1903 work, in 1913 produced a paper that presented the rocket equation and calculated the energies required to reach the Moon and nearby planets. In this talk, he proposed the use of atomic energy, using 400 kg of radium to power an interplanetary vehicle. His culminating work was L'Astronautique, published in 1930. A later version published in 1934 included details on interplanetary travel and applications of nuclear power.
On June 8, 1927, Robert gave a symposium for the French Astronautics Society titled L'exploration par fusées de la très haute atmosphère et la possibilité des voyages interplanétaires, concerning the exploration of outer space using rocket propulsion. Jean-Jacques Barre attended this lecture, and developed a correspondence with Esnault-Pelterie on the topic of rockets.
In 1929 Robert proposed the idea of the ballistic missile for military bombardment. By 1930, Robert and Jean-Jacques had persuaded the French War Department to fund a study of the concept. In 1931, the two began experimenting with various types of rocket propulsion systems, including liquid propellants. The same year he ran a demonstration of a rocket engine powered with gasoline and liquid oxygen. During an experiment with a rocket design using tetra-nitromethane he lost three fingers from his right hand during an explosion. Unfortunately their work failed to galvanize an interest in rocketry within France.
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