CAPE CANAVERAL, Fla. – In the Space Shuttle Main Engine Processing Facility at NASA’s Kennedy Space Center in Florida, a transportation canister is nearly closed around a Pratt Whitney Rocketdyne space shuttle main engine (SSME). This is the second of the 15 engines used during the Space Shuttle Program to be prepared for transfer to NASA's Stennis Space Center in Mississippi. The engines will be stored at Stennis for future use on NASA's new heavy-lift rocket, the Space Launch System (SLS), which will carry NASA's new Orion spacecraft, cargo, equipment and science experiments to space. For more information, visit http://www.nasa.gov/shuttle. Photo credit: NASA/Gianni Woods KSC-2012-1026

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.