Due to budget constraints experienced by NASA, the Russian RKA, the Japanese JAXA, the European ESA, and the Canadian ASC-CSA in the early 1990s their respective projects (the Japanese Kibo laboratory, the Soviet Mir-2, the American Freedom, and the European Columbus) were merged together into a single multi-national program managed collaboratively by the participating space agencies. The station’s ownership and use is laid out in a series of intergovernmental treaties and agreements that divided the station into two areas. Russia retains full ownership of the Russian Orbital Segment and is slated for completion by 2016, while the other international partners instead manage the US Orbital Segment collectively and was completed in 2011.
Since then the station has been expanded upon seeing regular visits from the Russian Proton and Soyuz rockets, and while they were in service the US Space Shuttles. And since May 2009 the permanent crew size has been expanded to six members and is expected to increase to seven once the Commercial Crew Program has become operational. The station however has had up to thirteen crewmembers aboard on three separate occasions during the final Shuttle ISS assembly missions. Having been continuously occupied for the past twelve years the International Space Station now holds the record for the longest inhabited Low Earth Object and has truly become an international effort with astronauts and cosmonauts having visited from fifteen different nations and is expected to remain operational until at least 2020 but could find itself extended to 2028 and possibly beyond even that. As the largest artificial satellite in orbit with a mass and volume greater than any previous station the ISS can be seen from the surface of the planet with the naked eye.
With the shuttles no longer being launched by the Americans, the Soyuz is being relied upon to deliver crew while unmanned cargo spacecraft operated by the Russians and Japanese are being used to service the station. However once the American Dragon spacecraft has been cleared, it is expected to help fill the void left by NASA’s space shuttle program and since May 2012 has been making regular delivery runs. This is the first step in what will be the privatization of Low Earth Orbit as the US administration signaled in 2010 that they would no longer fund their Constellation program, having instead turned their attention more fully to the prospect of a Heavy-lift Vehicle capable of making the trip to Mars.