NASA has kept two 747s set up as Space Shuttle transports. The downstairs passenger area of these jetliners has been as hollow inside as possible in order to carry the very special cargo. Known as the Shuttle Carrier Aircraft (SCA), the modified Boeing 747 jetliners originally were manufactured for commercial use. The 747 four-engine intercontinental-range, swept-wing "jumbo jets" entered commercial service in 1969.

NASA's space shuttle fleet began setting records with its first launch on April 12, 1981 and continued to set high marks of achievement and endurance through 30 years of missions. Starting with Columbia and continuing with Challenger, Discovery, Atlantis and Endeavour, the spacecraft has carried people into orbit repeatedly, launched, recovered and repaired satellites, conducted cutting-edge research and built the largest structure in space, the International Space Station. The final space shuttle mission, STS-135, ended July 21, 2011 when Atlantis rolled to a stop at its home port, NASA's Kennedy Space Center in Florida. As humanity's first reusable spacecraft, the space shuttle pushed the bounds of discovery ever farther, requiring not only advanced technologies but the tremendous effort of a vast workforce.