CAPE CANAVERAL, Fla. - At NASA's Kennedy Space Center in Florida, workers check data on the payload ground handling mechanism, or PGHM, in the Payload Changeout Room on Launch Pad 39A. The PGHM is being used to transfer the STS-125 mission payload into space shuttle Atlantis’ payload bay. STS-125 is the fifth and final shuttle servicing mission for NASA’s Hubble Space Telescope. The payload comprises four carriers holding various equipment for the mission. Atlantis is targeted to launch Oct. 14 on the 11-day mission. Photo credit: NASA/Jack Pfaller KSC-08pd2957

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.