The International Space Station (ISS) is a research facility currently being assembled in Low Earth Orbit. On-orbit construction of the station began in 1998, and is scheduled to be complete by 2011, with operations continuing until around 2015. , the ISS is the largest artificial satellite in Earth orbit, larger than any previous space station.

The ISS programme is a joint project among the space agencies of the United States (National Aeronautics and Space Administration - NASA), Russia (Russian Federal Space Agency - RKA), Japan (Japan Aerospace Exploration Agency - JAXA), Canada (Canadian Space Agency - CSA) and ten European nations (European Space Agency - ESA). The Brazilian Space Agency (AEB) participates through a separate contract with NASA. The Italian Space Agency (ASI) similarly has separate contracts for various activities not done within the framework of ESA's ISS projects (where Italy also fully participates). China has reportedly expressed interest in the project, especially if it would be able to work with the RKA, although it is not involved.

The space station is in a Low Earth Orbit, and can be seen from Earth with the naked eye. It orbits at an altitude of approximately 350 km (190 nautical miles) above the surface of the Earth, travelling at an average speed of 27,700 kilometres (17,210 mi) per hour, completing 15.7 orbits per day.

The ISS has been continuously staffed since the first resident crew, Expedition 1, entered the station on 2 November 2000. This has provided a permanent human presence in space for the last . At present, the station has the capacity for a crew of three. However, to fulfil an active research programme, it will be staffed by a resident crew of six beginning with Expedition 20. The crew of Expedition 19 is currently aboard.

Early crew members all came from the Russian and American space programmes until German ESA astronaut Thomas Reiter joined the Expedition 13 crew in July 2006, becoming the first crew member from another space agency. The station has been visited by astronauts from 16 different nations, and it was the destination of the first six space tourists.

Purpose

The International Space Station serves primarily as a research laboratory and is the largest ever launched into orbit. The station offers an advantage over spacecraft such as NASA's Space Shuttle because it is a long-term platform in the space environment, allowing long-duration studies to be performed, both on specific experiments and on the human crews that operate them. Long-term expedition crews conduct science daily (approximately 160 man-hours a week), across a wide variety of fields, including human research, life sciences, physical sciences, and Earth observation, as well as education and technology demonstrations. , 90 science investigations had been conducted on the ISS over 64 months of continuous research. In addition, there have been nine research racks and more than 7,700 kg (17,000 lb) of research equipment and facilities launched to the station. Scientific findings, in fields ranging from basic science to exploration research, are being published every month.