Technical survey of astronautics written in early 1962 by a French aeronautical engineer, in the fifth year of the space age. The book covers the mechanics of spaceflight (cosmic velocities, Hohmann transfer orbits, characteristic velocities), chemical propulsion and its propellants, artificial satellites and their civil and military applications, space medicine, radio guidance, and finally the ion, nuclear and photonic thrusters still confined to the laboratory. The thirteenth volume in the Le Rayon de la Science series of the Seuil Microcosme collections, it is heavily illustrated with both American and Soviet photographs and rounded out with a glossary and a short A to Z of astronautics.