Since the late 1960s, Pads A and B at Kennedy Space Center's Launch Complex 39 have served as backdrops for America's most significant manned space flight endeavors - Apollo, Skylab, Apollo-Soyuz and Space Shuttle.

Located on Merritt Island, Florida, just north of Cape Canaveral, the pads were originally built for the huge Apollo/Saturn V rockets that launched American astronauts on their historic journeys to the Moon and back. Following the joint U.S.-Soviet Apollo-Soyuz Test Project mission of July 1975, the pads were  modified to support Space Shuttle operations.

Both pads were designed to support the concept of mobile launch operations, in which space vehicles are assembled and checked out in the protected environment of the Vehicle Assembly Building, then transported by large tracked vehicles to the launch pad for final processing and launch. During the Apollo era, key pad service structures were mobile. For the Space Shuttle, two permanent service towers were installed at each pad for the first time, the Fixed Service Structure and the Rotating Service Structure.

On April 12, 1981, Shuttle operations commenced at Pad A with the launch of Columbia on STS-1. After 23 more successful launches from A, the first Space Shuttle to lift off from Pad B was the ill-fated Challenger in January 1986. Pad B was designated for the resumption of Shuttle flights in September 1988, followed by the reactivation of Pad A in January 1990.