History: NASA Archive Photography

The ISS combines the Japanese Kibō laboratory with three space station projects, the Soviet/Russian Mir-2, the American Freedom, and the European Columbus. Budget constraints led to the merger of these projects into a single multi-national program in the 1990s. The station consists of pressurized modules, external trusses, solar arrays and other components, which have been launched by Russian Proton and Soyuz rockets, and US Space Shuttles. It is currently being assembled in Low Earth Orbit. The construction began in 1998 and construction of the US Orbital Segment was completed in 2011; operations are expected to continue until at least 2020. The station can be seen from the Earth with the naked eye and, as of 2011, is the largest artificial satellite in Earth orbit with a mass and volume larger than that of any previous space station.
As mentioned it is a joint project between the five participating space agencies, NASA, the Russian RKA, the Japanese JAXA, the European ESA, and the Canadian CSA. The ownership and use of the space station is established in intergovernmental treaties and agreements which divide the station into two areas and allow Russia to retain full ownership of the Russian Orbital Segment, with the US Segment allocated between the other international partners. The station is serviced by Soyuz and Progress spacecraft, the Automated Transfer Vehicle, and the H-II Transfer Vehicle and has been visited by astronauts and cosmonauts from 15 different nations. The Space Shuttle, before its retirement was also used for cargo and crew transfer.
In 2012, it is expected that the American Commercial Resupply Service vehicles, the SpaceX Dragon and the Orbital Sciences' Cygnus, will begin to service the space station with cargo.
On February 1st, 2010, the American Commercial Crew Development (CCDev) program was initiated with the purpose of creating commercially operated spacecraft capable of delivering crew to the ISS. These spacecraft are expected to become operational in the mid 2010s.