KENNEDY SPACE CENTER, FLA. -- The shuttle carrier aircraft, or SCA, sits on the tarmac at Kennedy Space Center's Shuttle Landing Facility after demate from Atlantis. Several service vehicles have arrived to prepare the aircraft for its flight back to Johnson Space Center in Texas. Atlantis arrived at Kennedy Space Center atop the SCA on July 3 after a three-day, cross-country flight due to fuel stops and weather delays. Touchdown was at 8:27 a.m. EDT. Atlantis landed at Edwards Air Force Base in California on June 22 to end mission STS-117. Photo credit: NASA/George Shelton. KSC-07pd1795

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.