The crawler-transporters are a pair of
tracked vehicles used to transport spacecraft from NASA's Vehicle
Assembly Building (VAB) along the Crawlerway to Launch Complex 39. They
were originally used to transport the Saturn IB and Saturn V rockets
during the Apollo, Skylab and Apollo–Soyuz programs. They were then used
to transport Space Shuttles from 1981 to 2011. The crawler-transporters
carry vehicles on the Mobile Launcher Platform, and after each launch
return to the pad to take the platform back to the VAB.
