Robert Goddard with the "hoopskirt" rocket before an attempted launch on September 29, 1928.

Robert Goddard was among the few people who independently discovered the rocket as the key to space before World War I, and was one of three (along with Tsiolkovsky and Oberth) who worked out all the equations. He went on to create the world's first flying, liquid-fuel rocket and made many other pioneering contributions to rocket technology.