KENNEDY SPACE CENTER, FLA. -- In the Orbiter Processing Facility, one of two Materials International Space Station Experiments, or MISSE, is lowered into space shuttle Endeavour's payload bay for installation. The MISSE is part of the payload onboard Endeavour for mission STS-123. The MISSE project is a NASA/Langley Research Center-managed cooperative endeavor to fly materials and other types of space exposure experiments on the International Space Station. The objective is to develop early, low-cost, non-intrusive opportunities to conduct critical space exposure tests of space materials and components planned for use on future spacecraft. Photo credit: NASA/Kim Shiflett KSC-07pd3319

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.