II.

Spacecraft and Supporting Systems

The main portion of the Skylab space station was the 27 m (89 ft) long orbital workshop. This two-story structure was constructed inside the converted second stage of a Saturn 1B rocket. One workshop floor provided living quarters for the crew and was divided into four sections: the sleep compartment, the waste-management compartment, the wardroom, and the experiment work area. The second floor was devoted to other scientific experiments that required large areas or needed external views. Solar arrays provided electrical power and were located on opposite ends of the long workshop.

Skylab's Apollo telescope mount (ATM) was the first manned solar observatory put into space. It was composed of eight integrated telescopes that studied the sun's corona, or wispy-looking outer atmosphere (see Sun). The ATM had its own solar arrays to use as independent power sources and its own guidance and control system.

The multiple docking adapter (MDA) was a cylindrical structure about 5.2 m (about 17 ft) long and 3 m (10 ft) in diameter that was used to link the Apollo CSM to Skylab. The MDA enabled the transfer of astronauts, equipment, power, and electrical signals between the CSM and Skylab. The MDA had two docking ports, hatches designed to lock with the Apollo CSM. One port was used for normal operations while the second acted as a backup.

Positioned between the MDA and orbital workshop areas was the airlock module, which provided an area for the crew to perform space walks, or extravehicular activities (EVAs), outside the space station. This module also contained control panels for electrical power, temperature control, telecommunications, data handling, and data recording.

The Apollo CSM, the same craft used for the lunar landing programs, provided transportation to and from Skylab for the astronauts. The CSM also enabled the astronauts to store and return experiments, as well as the accompanying data, to researchers on the ground. When the CSM was docked with Skylab, all CSM systems except communications were turned off to conserve energy.

Skylab and its crews were launched into orbit by Saturn rockets developed for the Apollo program. A two-stage Saturn V rocket sent the unmanned Skylab module into orbit. Smaller Saturn 1B launch vehicles carried the three crews in Apollo command and service modules to rendezvous with Skylab.