Mankind has dreamed of traveling into space for centuries, but in the twentieth century, scientific and technical capabilities converged with this dream for the first time. The potential of the rocket was realized independently by three different men, born in different countries, who never met each other in person. These men Tsiolkovski of Russia, Goddard of the U.S. and Oberth of Germany, each derived the same conclusions about the future of space travel.  Their conclusions that become the basic working formulas of the space age.