Skylab was operated by the United States from 1971 to 1979. It operated during a time when the space race was on full blast. Though it was the fifth space station (the first through fourth being the stations launched by the U.S.S.R.), it was the first truly long term habitat in space. Many groundbreaking discoveries were made aboard Skylab although, some of the most important discoveries related to living in space and the difficulties with existing in a zero gravity environment. Skylab was de-orbited on July, 11 1979. It would not be until 1998 with the launch of the first modules of the International Space Station that the United States would participate directly with long term space habitation.
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