Skylab was the first US space station, launched in 1973. It was the only space station the US had until the launch of the International Space Station in 1998. Skylab was a workshop for astronauts to conduct experiments in microgravity and observe the Earth from space. It was also used to test new technologies and equipment for future space missions. Skylab remained in orbit until 1979 when it re-entered the Earth's atmosphere and broke apart.