The International Space Station (ISS) is a multinational space laboratory orbiting Earth at an altitude of about 400 kilometers. It is a joint project involving NASA, Roscosmos, the European Space Agency, the Japan Aerospace Exploration Agency, and the Canadian Space Agency. Since its first module was launched in 1998, the ISS has hosted continuous human habitation and serves as a platform for scientific research, technology testing, and international cooperation in space exploration.