Claim: The International Space Station functions as a microgravity environment.

The International Space Station -LRB- ISS -RRB- is a space station , or a habitable artificial satellite , in low Earth orbit . Its first component launched into orbit in 1998 , and the ISS is now the largest man-made body in low Earth orbit and can often be seen with the naked eye from Earth . The ISS consists of pressurised modules , external trusses , solar arrays , and other components . ISS components have been launched by Russian Proton and Soyuz rockets , and American Space Shuttles .   The ISS serves as a microgravity and space environment research laboratory in which crew members conduct experiments in biology , human biology , physics , astronomy , meteorology , and other fields . The station is suited for the testing of spacecraft systems and equipment required for missions to the Moon and Mars . The ISS maintains an orbit with an altitude of between 330 and by means of reboost manoeuvres using the engines of the Zvezda module or visiting spacecraft . It completes orbits per day .   The ISS is the ninth space station to be inhabited by crews , following the Soviet and later Russian Salyut , Almaz , and Mir stations as well as Skylab from the US . The station has been continuously occupied for since the arrival of Expedition 1 on 2 November 2000 . This is the longest continuous human presence in low Earth orbit , having surpassed the previous record of held by Mir . The station is serviced by a variety of visiting spacecraft : the Russian Soyuz and Progress , the American Dragon and Cygnus , the Japanese H-II Transfer Vehicle , and formerly the Space Shuttle and the European Automated Transfer Vehicle . It has been visited by astronauts , cosmonauts and space tourists from 17 different nations .   After the US Space Shuttle programme ended in 2011 , Soyuz rockets became the only provider of transport for astronauts at the International Space Station , and Dragon became the only provider of bulk cargo return to Earth -LRB- called downmass -RRB- . Soyuz has very limited downmass capability .   The ISS programme is a joint project among five participating space agencies : NASA , Roscosmos , JAXA , ESA , and CSA . The ownership and use of the space station is established by intergovernmental treaties and agreements . The station is divided into two sections , the Russian Orbital Segment -LRB- ROS -RRB- and the United States Orbital Segment -LRB- USOS -RRB- , which is shared by many nations . , the American portion of ISS is being funded until 2024 . Roscosmos has endorsed the continued operation of ISS through 2024 but has proposed using elements of the Russian Orbital Segment to construct a new Russian space station called OPSEK .   On 28 March 2015 , Russian sources announced that Roscosmos and NASA had agreed to collaborate on the development of a replacement for the current ISS . NASA later issued a guarded statement expressing thanks for Russia 's interest in future co-operation in space exploration but fell short of confirming the Russian announcement .