CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, a crawler-transporter moves toward NASA's new mobile launcher (ML) support structure. The crawler will transport the ML from a construction site, north of the Vehicle Assembly Building, to the Mobile Launcher east park site. Once there, the ML can be outfitted with ground support equipment, such as umbilicals and access arms, for future rocket launches. It took about two years to construct the 355-foot-tall structure, which will support NASA's future human spaceflight program. The base of the launcher is lighter than space shuttle mobile launcher platforms so the crawler-transporter can pick up the heavier load of the tower and a taller rocket. Photo credit: NASA/Jack Pfaller KSC-2010-4877

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.