CAPE CANAVERAL, Fla. -- In the transfer aisle of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, this image shows the rear of space shuttle Endeavour and it covered three main engines as a worker attaches an overhead crane. The crane will lift the spacecraft into a high bay where it will be attached to its external fuel tank and solid rocket boosters for its final mission, STS-134. Endeavour and its STS-134 crew will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer, a high-pressure gas tank, additional spare parts for Dextre and micrometeoroid debris shields to the International Space Station. Launch is targeted for April 19 at 7:48 p.m. EDT. For more information visit, http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Frankie Martin KSC-2011-1924

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.