International Space Station – ISS
The International Space Station (ISS) is a habitable artificial satellite in low Earth orbit. It is the largest artificial body in orbit and can be seen with naked eye from Earth. The ISS consists of pressurized modules, external trusses, solar arrays, and other components. ISS components have been launched by American Space Shuttle missions, and Russian Proton and Soyuz rockets. First component was launched into orbit in 1998 and the ISS configuration is still being updated with new components, running through at least 2024. The ISS serves as a micro-gravity and space environment research laboratory in which 6 crew members conduct scientific experiments in biology, physics, astronomy, meteorology, and other fields primarily important for further space exploration. The station also conducts tests of spacecraft systems and equipment required for missions to the Moon and Mars. The space station maintains an orbit with an altitude of between 330 and 435 km (205 and 270 mi) by means of reboost manoeuvres using the engines on Russian Service Module “Zvezda” or visiting spacecraft. It completes 15.54 orbits per day.