The International Space Station (ISS) has been continuously occupied by rotating crews of astronauts and cosmonauts for over 20 years. The ISS was first occupied on November 2, 2000, and has been continuously inhabited since then, making it the longest-serving human-made object in low Earth orbit. Over the course of its 20 years of operation, the ISS has played a vital role in space exploration, scientific research, and international cooperation.
During its 20 years of operation, the ISS has hosted more than 250 people from 19 different countries. It has also been visited by over 100 spacecraft, including space shuttles, Soyuz spacecraft, and cargo resupply vehicles. The ISS has conducted thousands of scientific experiments in fields such as biology, physics, astronomy, meteorology, and more. It has also served as a platform for technological development, including the development of new materials, medical treatments, and space technologies.