KENNEDY SPACE CENTER, Fla. -- STS-118 Mission Specialist Alvin Drew completes suitup for the simulated launch countdown that concludes the terminal countdown demonstration test, or TCDT. The STS-118 crew has been at Kennedy for the TCDT activities that also include M-113 training, payload familiarization and emergency egress training at the pad. The mission is the 22nd flight to the International Space Station and Space Shuttle Endeavour will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. Photo credit: NASA/George Shelton KSC-07pd1962

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.