NASA's Space Shuttle Program was developed and designed in the 1970's. The goal was a reusable spacecraft, able to start like a rocket and land like an airplane, with frequent missions and sinking operational costs. The prototype "Enterprise" flew atmospheric flights and landing tests (ALT). The first orbiter was called "Columbia" (maiden voyage in 1981). The other orbiters built were Challenger (lost in 1986 after STS-51-L launch), Discovery, Atlantis and Endeavour. After the 2003 Columbia accident (STS-107), the Space Shuttle helped to complete the International Space Station. The Program ended after the landing of STS-135 in July 2011.