Space Shuttle landing at Edwards, the orbiter was flown back to the KSC on the Shuttle Carrier Aircraft, a specially modified Boeing 747. The first orbiter, "Enterprise", was built in 1976, used in Approach and Landing Tests and had no orbital capability. Four fully operational orbiters were initially built: "Columbia", "Challenger", "Discovery", and "Atlantis". Of these, two were lost in mission accidents: "Challenger" in 1986 and "Columbia" in 2003, with a total of fourteen astronauts killed. A fifth operational (and sixth in total) orbiter, "Endeavour", was built in 1991 to replace "Challenger". The Space Shuttle was retired from service upon the conclusion
Space Shuttle retirement Space Shuttle retirement The retirement of NASA's Space Shuttle fleet took place from March to July 2011. "Discovery" was the first of the three active space shuttles to be retired, completing its final mission on March 9, 2011; "Endeavour" did so on June 1. The final shuttle mission was completed with the landing of "Atlantis" on July 21, 2011, closing the 30-year Space Shuttle program. The Shuttle was presented to the public in 1972 as a "space truck" which would, among other things, be used to build a United States space station in low earth orbit in the early 1990s