How Many Orbiters Are There?
Today, three orbiters fly into space. They are Discovery, Atlantis and Endeavour. Since the shuttle began flying in 1981, two orbiters, Columbia and Challenger, have been lost due to accidents. One other orbiter, Enterprise, never flew into space. It was built to test how the orbiters would work. Now it’s at a Smithsonian Museum center near Washington, D.C.