Skylab. NASA Skylab space station

The idea that ultimately became Skylab first surfaced in 1962 as a proposal to convert a spent Saturn upper stage (Saturn V S-II stage) into an orbital workshop. In 1968, the Marshall Space Flight Center proposed an alternative to the wet workshop concept of refurbishing a space station in orbit. Instead, a fully equipped dry workshop could be launched as a complete unit ready for occupancy. Skylab became the free world's first space station. Launched in May 1973, the Skylab space station was occupied in succession by three teams of three crewmembers. These crews spent 28, 59, and 84 days respectively, orbiting the Earth and performing nearly 300 experiments. This view of Skylab in orbit was taken by the Skylab 4 (the last Skylab mission) crew.
NASA Identifier: MSFC-7449862