In 1903, Konstantin E. Tsiolkovsky (1857–1935), a Russian high school teacher, completed the first scientific paper on the use of rockets for space travel. Several years later, Robert H. Goddard (1882–1945) of the United States and Hermann Oberth (1894–1989) of Germany awakened wider scientific interest in space travel. These three men worked individually on many of the technical problems of rocketry and space travel. They are known, therefore, as the “fathers of space flight.”

In 1919, Goddard wrote the paper, “A Method of Reaching Extreme Altitudes,” which explained how rockets could be used to explore the upper atmosphere and described a way to send a rocket to the moon. During the 1920s Tsiolkovsky wrote a series of new studies that included detailed descriptions of multi-stage rockets. In 1923, Oberth wrote The Rocket into Interplanetary Space, which discussed the technical problems of space flight and also described what a spaceship would be like.