The International Space Station is considered as the most complex international engineering and scientific project in the history of the structures humans have set in space. By now, the ISS is the largest man-made station in the orbit and is visible to the human eye.

A lot of countries contributed in building the ISS; these include the USA, Japan, United Kingdom and 13 others. It cost them $100 billion dollars to build it, and the station is still completely functional until today. Boarding of human staff in the space station has started since November 2000. In the process of creating the station, it took them 115 space flights to complete, gradually building it in orbit.

The ISS is a laboratory for the latest technologies and stands as an observation platform for space, astronomy, geological and environmental research. It is a permanently occupied outpost in the outer space and serves as the catalyst to further space exploration. It flies at an average altitude of 400 kilometers (248 miles) above Earth at the speed of about 28,000 kph (17,500 mph). The ISS Astroviewer website tracks the orbit of the station in real time.

ISS is the ninth space station that can be inhabited by humans in space. Its predecessors are the Soviet now Russia Almaz, Mir, Salyut and the U.S. Skylab. It has been occupied by humans for over 14 years and 342 days since the arrival of Expedition 1 in November 2000. This is considered as the longest-running human presence in the outer space, surpassing the record of 9 years and 357 days by Mir.

The station is maintained by visiting spacecraft expeditions by Soyuz, the automated transfer vehicle, Progress, Dragon, Cygnus and the H-II Transfer Vehicle. The space station has also been visited by cosmonauts, astronauts and space tourists from 17 different countries.

The Space shuttle program of the U.S. ended in 2011, thus making only the Soyuz rockets the only provider of transport for astronauts to ISS and Dragon became the provider of cargo return to Earth services. On Mar. 28, the Roscosmos and NASA agreed to collaborate in the development of the replacement of ISS.