CAPE CANAVERAL, Fla. ––Inside the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida, a technician monitors the progress as a crane begins to lift an Apollo era diesel engine from crawler-transporter 2 CT-2). New engines will be installed later this month. Work is in progress in high bay 2 to upgrade CT-2 so that it can carry NASA’s Space Launch System heavy-lift rocket, which is under design, and new Orion spacecraft to the launch pad. The crawler-transporters were used to carry the mobile launcher platform and space shuttle to Launch Complex 39 for space shuttle launches for 30 years. Photo credit: NASA/Kim Shiflett KSC-2012-1344

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.