CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, workers offload the Alpha Magnetic Spectrometer (AMS) from an Air Force C-5M aircraft on the Shuttle Landing Facility runway. The state-of-the-art particle physics detector arrived at Kennedy from Europe and will operate as an external module on the International Space Station to study the universe and its origin by searching for dark matter. AMS will fly to the station aboard space shuttle Endeavour's STS-134 mission targeted to launch Feb. 26, 2011. Photo credit: NASA/Frankie Martin KSC-2010-4542

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.