Iss (pronounced EES) is a Russian space station currently being operated by the Russian Federal Space Agency. It has been in orbit since 1998 and is the largest artificial satellite in orbit, with a mass of over 200 metric tons. The station is primarily used for research and as a base for future missions to Mars and other destinations in the solar system. It has also been used as a test bed for new technologies such as 3D printing in space.
The ISS is modular in design, with each module having a specific purpose. The modules are launched into orbit separately and then docked together to form the complete station. The first module, Zarya, was launched in 1998 and was followed by the Unity module, which was launched in 1999. Since then, various other modules have been added, including living quarters, laboratories, exercise facilities and an airlock.
The ISS has a crew of six astronauts who live and work on board the station for periods of around six months at a time. They carry out research experiments in fields such as biology, physics and materials science. They also maintain the station itself and carry out repair work when necessary. From time to time, visiting crews from other countries will come to stay on the ISS, providing additional manpower for scientific work or construction projects.
The ISS orbits Earth at an altitude of around 400 kilometers (250 miles), completing one orbit every 92 minutes. It is visible to the naked eye from Earth as it reflects sunlight back down to us; however it is not always possible to see it due to its orbital path taking it into Earth’s shadow at times. As well as being visible from Earth with the naked eye, the ISS can also be seen using binoculars or a telescope – although it appears as nothing more than a bright star-like object moving quickly across the sky!