What is a space shuttle?
NASA's space shuttle, also called the Space Transportation System (STS), takes off from Earth like a rocket but lands like an aircraft. It cannot fly to the Moon, but is used to orbit Earth, where the crew can do scientific work, place satellites in orbit, and visit orbiting space stations. Usually five to seven crew members ride the space shuttle, which have all been launched from Kennedy Space Center in Florida. Six shuttles have been built: the first orbiter, Enterprise, was built in 1974 for testing purposes. Five others have gone into space: Columbia, Challenger, Discovery, Atlantis, and Endeavour. The space shuttle Challenger disintegrated 73 seconds after launch in 1986, killing all seven astronauts; Endeavour was built as its replacement. Columbia broke apart during re-entry in 2003, also killing all seven onboard. The final space shuttle mission was in 2011, when Atlantis returned to the Kennedy Space Center on July 20.
NASA announced that Project Constellation would be the next space program, but that was shelved due to budgetary concerns. Instead, the NASA Authorization Act of 2010 designated the Space Launch System to replace the space shuttle program, with the first scheduled missionan unmanned mission around the Moonto take place in 2017.