CAPE CANAVERAL, Fla. – In the Space Station Processing Facility at NASA's Kennedy Space Center, from left, STS-119 Mission Specialist Richard Arnold, Commander Lee Archambault, and Mission Specialists John Phillips and Steve Swanson familiarize themselves with hardware slated to fly on their upcoming space shuttle mission. On the STS-119 mission, space shuttle Discovery will carry the S6 truss segment to complete the 361-foot-long backbone of the International Space Station. The truss includes the fourth pair of solar array wings and electronics that convert sunlight to power for the orbiting laboratory. Launch is targeted for Feb. 12, 2009. Photo credit: NASA/Kim Shiflett KSC-08pd2177

The Space Shuttle program was the United States government's manned launch vehicle program from 1981 to 2011, administered by NASA and officially beginning in 1972. The Space Shuttle system—composed of an orbiter launched with two reusable solid rocket boosters and a disposable external fuel tank— carried up to eight astronauts and up to 50,000 lb (23,000 kg) of payload into low Earth orbit (LEO). When its mission was complete, the orbiter would re-enter the Earth's atmosphere and lands as a glider. Although the concept had been explored since the late 1960s, the program formally commenced in 1972 and was the focus of NASA's manned operations after the final Apollo and Skylab flights in the mid-1970s. It started with the launch of the first shuttle Columbia on April 12, 1981, on STS-1. and finished with its last mission, STS-135 flown by Atlantis, in July 2011.