stylistic:style_transfer
Skylab sequence

In 1965, the Apollo Applications Program (AAP) was created to look into science missions that could be performed using Apollo hardware. Much of the planning centered on the idea of a space station. Wernher von Braun's earlier (1964) plans employed a " wet workshop " concept, with a spent S-II Saturn V second stage being launched into orbit and outfitted in space. The next year AAP studied a smaller station using the Saturn IB second stage. By 1969, Apollo funding cuts eliminated the possibility of procuring more Apollo hardware and forced the cancellation of some later Moon landing flights. This freed up at least one Saturn V, allowing the wet workshop to be replaced with the "dry workshop" concept: the station (now known as Skylab) would be built on the ground from a surplus Saturn IB second stage and launched atop the first two live stages of a Saturn V. A backup station, constructed from a Saturn V third stage, was built and is now on display at the National Air and Space Museum.

Skylab was the only launch not directly related to the Apollo lunar landing program. The only significant changes to the Saturn V from the Apollo configurations involved some modification to the S-II to act as the terminal stage for inserting the Skylab payload into Earth orbit, and to vent excess propellant after engine cutoff so the spent stage would not rupture in orbit. The S-II remained in orbit for almost two years, and made an uncontrolled re-entry on January 11, 1975.

Three crews lived aboard Skylab from May 25, 1973, to February 8, 1974. Skylab remained in orbit until July 11, 1979.