December 15, 1923 – Oberth publishes major work
Hermann Julius Oberth (June 25, 1894 – December 28, 1989) self-publishes Die Rakete zu den Planetenräumen (“By Rocket into Planetary Space”) after its rejection as a doctoral thesis.
. . . an Austro-Hungarian-born, German and Romanian physicist, and, along with the Russian Konstantin Tsiolkovsky and the American Robert Goddard, one of the founding fathers of rocketry and astronautics. The three were never active collaborators: instead, their parallel achievements occurred independently of one another.