Rocket technology has its origins in ancient and medieval civilizations. Around A.D. 160 the Greek mathematician Hero of Alexandria invented the Sphere of Aeolus, the first known device to demonstrate the principles of propulsion. It consisted of two tubes attached to opposing sides of a sphere. When water was boiled in the sphere, steam escaping from the tubes produced enough pressure to spin the sphere. Hero's invention, however, and the principles it demonstrated elicited no more than idle curiosity from his contemporaries.

In China, rocketry advanced more quickly, closely following the invention of gunpowder. A Chinese text from the thirteenth century describes "arrows of flying fire" that could be launched without the aid of a bow. Essentially hand-held Roman candles, these rockets were also used for religious ceremonies and celebrations.

Eventually knowledge of these weapons spread from China to Mongolia and the Arab world...