CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, space shuttle Discovery approaches Launch Pad 39A during "rollout" from the Vehicle Assembly Building to Launch Pad 39A. It took the shuttle, attached to its external fuel tank, twin solid rocket boosters and mobile launcher platform, about six hours to complete the move atop a crawler-transporter. Rollout sets the stage for Discovery's STS-133 crew to practice countdown and launch procedures during the Terminal Countdown Demonstration Test in mid-October. Targeted to liftoff Nov. 1, Discovery will take the Permanent Multipurpose Module (PMM) packed with supplies and critical spare parts, as well as Robonaut 2 (R2) to the International Space Station. Photo credit: NASA/Frankie Martin KSC-2010-4725

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.