Skylab

/skuy"lab'/, n.

a U.S. earth-orbiting space station that was periodically staffed by three separate crews of astronauts and remained in orbit 1973-79.

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First U.S. space station.

Launched into Earth orbit in 1973 on a Saturn V rocket, it used as its main habitat the vehicle's third stage, which had been outfitted as a workshop. Its apparatus included a powerful solar telescope and equipment for Earth-and materials-sciences research and for studies of the human body's adaptation to weightlessness. Three successive astronaut crews conducted research aboard Skylab for a total of 171 days in 1973–74. Because its thermal shielding was damaged during launch, its first crew took up and installed an improvised sunshade to prevent the station from seriously overheating. Although plans called for Skylab to be reused, increased solar activity caused its orbit to degrade faster than expected. In 1979 it entered Earth's atmosphere and broke up, with debris spreading over the southeastern Indian Ocean and a sparsely populated section of Western Australia.

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▪ United States space station

 first U.S. (United States) space station, launched into Earth orbit on May 14, 1973. Three successive crews of visiting astronauts carried out investigations of the human body's adaptation to the space environment, studied the Sun in unprecedented detail, and undertook pioneering Earth-resources observations.

 Skylab was an outcome of the Apollo Applications Program set up by the National Aeronautics and Space Administration (NASA) in 1965 to adapt spacecraft and systems developed for the U.S. Moon-landing program to a variety of scientific missions. As a first step toward establishing a long-term manned platform in space, Skylab made use of a Saturn V Moon rocket, whose third stage was outfitted as a habitat and ready-to-use orbital workshop, and the Command and Service modules of Apollo (Apollo program) spacecraft, which ferried the station's crews and small amounts of supplies. Although limited by its consumable resources in the same way as the Soviet Union's first-generation Salyut stations, Skylab was much roomier and capable of more research. Its main scientific instrument, the Apollo Telescope Mount, incorporated a number of component telescopes and other devices for observing the Sun over a broad range of the electromagnetic spectrum, from visible light through X rays.

      During Skylab's ascent a thermal-meteoroid shield was ripped off, which led to the loss of one of the lateral solar power arrays that was to supply electricity to the station and prevented full extension of the other. During their 28-day mission, the first three-man crew deployed an improvised “parasol” sunshade (later fortified with an overlying sun shield) to prevent serious overheating of the station and released the jammed solar array. Skylab hosted two additional three-man crews for missions lasting 59 and 84 days, the latter a space endurance record at the time. Although plans called for Skylab to be used again, increased solar activity caused its orbit to degrade faster than expected. On July 11, 1979, it entered the atmosphere, broke up, and scattered debris over the southeastern Indian Ocean and Western Australia.

David M. Harland

 

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