Skylab was launched and operated by NASA and was the United States' first space station. Skylab orbited Earth from 1973 to 1979, and included a workshop, a solar observatory, and other systems. It was launched uncrewed by a modified Saturn V rocket, with a weight of . Three crewed missions to the station, conducted between 1973 and 1974 using the Apollo command and service module (CSM) atop the smaller Saturn IB, each delivered a three-astronaut crew. On the last two crewed missions, an additional Apollo / Saturn IB stood by ready to rescue the crew in orbit if it was needed.
