CAPE CANAVERAL, Fla. -- A tug boat pulls the Space Shuttle Program's last external fuel tank, ET-122, toward the Turn Basin at NASA's Kennedy Space Center in Florida. The tank traveled 900 miles by sea from NASA's Michoud Assembly Facility in New Orleans aboard the Pegasus Barge. Next, the tank will be offloaded and moved to Kennedy's Vehicle Assembly Building where it eventually will be attached to space shuttle Endeavour for the STS-134 mission to the International Space Station. STS-134, targeted to launch in Feb., 2011, currently is scheduled to be the last mission in the Space Shuttle Program. The tank, which is the largest element of the space shuttle stack, was damaged during Hurricane Katrina in August 2005 and restored to flight configuration by Lockheed Martin Space Systems Company employees. Photo credit: NASA/Frankie Martin KSC-2010-4834

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.