L’Astronautique (Complément).

Inscribed by Esnault-Pelterie on the cover. Delivered as a communication to the Société des Ingénieurs Civils de France on 25 May 1934 and published the following year, this offprint brings his 1930 book L’Astronautique (also in this collection) up to date rather than replacing it, reworking the chapters that had become outdated and adding a historical survey of developments from 1930–34: the founding of the American Interplanetary Society and David Lasser’s The Conquest of Space (also in this collection), the fatal explosion of Reinhold Tiling’s stratospheric rocket in Germany in 1933, Ary Sternfeld’s Initiation à la Cosmonautique, and the founding of the British Interplanetary Society in 1934.

A section on N. A. Rynin’s nine-volume Leningrad encyclopedia of interplanetary travel describes having a colleague translate its tables of contents, since Esnault-Pelterie could not read Russian himself. The reworked trajectory chapter credits a 1934 paper by Sternfeld with a counterintuitive finding — that beyond a certain orbit ratio, a spacecraft can save propellant by overshooting its destination out toward infinity before returning, rather than transferring directly — a maneuver now called the bi-elliptic transfer, though Esnault-Pelterie himself doubted it had much practical use.

The book closes with appended tables and a large folding nomogram for computing chemical dissociation equilibria in combustion gases.