The Space Transportation System, or Space Shuttle for short was a flawed, beautiful, complex and innovative machine. It combined the aerodynamic characteristics of an aeroplane that can glide land and be reused, with rocket technology to provide the thrust required to get into orbit. However, as the shuttle was designed in the 1970s and first flew in 1981, it was fundamentally limited by the technology available at the time. There were three components to the space transportation system. The orbiter was the plane-like component that rode into orbit on the back of a large orange-coloured cylinder. Inside the external tank were two vessels, one containing liquid oxygen and the other liquid helium. Both liquids were pumped to the main shuttle engines situated at the back of the orbiter. Strapped to the sides of the external tank were the solid rocket boosters.