Hermann Julius Oberth (June 25, 1894—December 28, 1989) was a German physicist, and one of the founding fathers of rocketry and astronautics.
In 1922, his doctoral dissertation on rocket science was rejected as "utopian". He had the 92-page work privately published as the controversial Die Rakete zu den Planetenräumen (By Rocket into Planetary Space). (In 1929, Oberth would expand this to a 429-page work entitled Wege zur Raumschiffahrt or Ways to Spaceflight.)
In autumn 1929, Oberth launched his first liquid fuel rocket, named Kegeldüse. He was helped in this experiment by his students at the Technical University of Berlin, one of whom was Wernher von Braun, who would later head the wartime project to develop the rocket officially called the A4, but far better known today as the V-2.