Hermann Oberth was born on 25 June 1894, to a German family in Transylvania, a region of Austria — Hungary and now a part of Rumania. When he was 11 years old, Hermann had become fascinated by spaceflight afler reading Jules Verne's From the Earth to the Moon.
Oberth’s book appeared in 1923 under the title “The Rocket into Interplanetary Space”. In his book, Hermann Oberth focused on rocket dynamics. He considered the powered vertical flight through the atmosphere and introduced a concept of the optimal velocity that minimizes propellant consumption. He showed how a rocket could achieve the velocity allowing it to escape Earth's gravity. He described the details of liquid-propellant engines and calculated propellant exhaust velocities. Oberth introduced a number of ideas such as rocket staging, film cooling of the engine walls, and strengthening the structure by pressurizing propellant tanks.
The book presented a detailed design of a two-stage rocket with extensive supporting engineering calculations. The rocket used liquid oxygen as an oxidizer. The fuel was liquid hydrogen for the second -(upper) stage engine and the alcohol-water mixture for the first- (lower) stage engine. The latter combination would be used in the famous German A-4 (V-2) ballistic missile in 1940s.
Oberth joined the German Society for Space Traveland became its president in 1929.
Hermann Oberth played an important role in practical development of rocketry in Germany in the 1930s and provided inspiration for a generation of.