Space Shuttle.
The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated from April 12, 1981, to July 21, 2011, by the National Aeronautics and Space Administration in the United States. Launched from the Kennedy Space Center in Florida, five Space Shuttle orbiter vehicles flew on a total of 135 missions during 30 years. They conducted science experiments in orbit, helped build the International Space Station, and launched numerous satellites, interplanetary probes, and the Hubble Space Telescope. Four fully operational orbiters were initially built: Columbia, Challenger, Discovery (pictured), and Atlantis. Lost in mission accidents were Challenger in 1986 and Columbia in 2003, with a total of fourteen astronauts killed. A fifth operational orbiter, Endeavour, was built in 1991 to replace Challenger. The Space Shuttle was retired from service upon the conclusion of Atlantis's final flight.
