The Space Shuttle was designed as a reusable orbiting spacecraft, and operated by NASA. Its official title was Space Transportation System. The first free flight was in August 1977. Operational flights began in 1982. Space Shuttles were used on 135 missions from 1981 to 2011, all launched from the Kennedy Space Center in Florida. As a result, many satellites, interplanetary probes, and the Hubble Space Telescope were launched safely. In addition, the shuttles carried out science experiments in orbit; and helped in building and servicing of the International Space Station. The Shuttle fleet's total mission time was 1322 days, 19 hours, 21 minutes and 23 seconds.
The Shuttle was made of the Orbiter Vehicle (the bit we normally think of as a the shuttle), a pair of recoverable solid rocket boosters, and the external tank containing liquid hydrogen and liquid oxygen and used for takeoff. The Shuttle was launched vertically, like a conventional rocket. During orbit the shuttle used its on-board engines. These were also used in r-entry to the Earth's atmosphere. When it reached the ground, the shuttle glided to a runway landing at Edwards Air Force Base in California or at the Shuttle Landing Facility at the Kennedy Space Center at Florida. After the landings at Edwards, the orbiter was flown back to KSC on the Shuttle Carrier Aircraft, a specially modified Boeing 747.
The first orbiter, Enterprise, was built for tests and could not orbit. Four fully operational orbiters were built: Columbia, Challenger, Discovery, and Atlantis. Challenger and Columbia were destroyed in mission accidents in 1986 and 2003 and fourteen astronauts were killed. A fifth operational orbiter, Endeavour, was built in 1991 to replace Challenger. The Space Shuttle was retired from service after Atlantis 's final flight on July 21, 2011.
The orbiter is named after the British HMS Endeavour, the ship which took Captain James Cook on his first voyage of discovery (1768–1771). This is why the name is spelled in the British English manner, rather than the American English ("Endeavor").
