What are space stations?

Astronauts spend a few days at a time in space aboard the space shuttle. Longer periods, weeks , months or over a year, have been spent on the Mir space station. A space station is a craft permanently in orbit round the Earth. It is where the astronauts work in space. It is considered as home in space of the astronauts in conditions of zero gravity.

Space stations are usually made up of several modules that are sent into orbit, one at a time, and assembled in space. Some space stations such as the Russian Mir, stayed up for many years, and their crews remained in space for months at a time.

Russian cosmonauts have lived on seven different space stations since 1971. The first were all called Salyut, but Mir was the last and most successful one. Mir was too large to launch in one go. Parts were transported separately and assembled in space. Mir was continously inhabited by cosmonauts from February 1987 to mid-1999.

The International Space Station (ISS) is now being constructed in orbit around Earth. It will take about 70 flights by Russian Proton rockets and American shuttles to trasport all the parts into space for assembly. The first arrived in 1998 and the station was fully completed last 2004. A cooperative effort by 16 nations, the ISS provided living-quarters and science laboratories for up to 7 astronauts.