The ISS is the ninth space station to be crewed, following the Russian Salyut, Almaz, and Mir and the American Skylab.
To date, 230 people from 18 countries have gone up to the International Space Station. ISS has been continuously occupied since November 2000, with international crews of six taking turns to conduct various experiments in space.
The ISS is capable of receiving six spaceships at once. A spacecraft can arrive at the space station as soon as six hours after launching from Earth. Currently, there are four different cargo spacecraft delivering science, cargo, astronauts or supplies: Orbital ATK’s Cygnus, SpaceX’s Dragon, JAXA’s HTV, and the Russian Progress.
CONSTRUCTIONThe space station is 357 feet end-to-end, comprising the modules, the integrated truss structure, and the solar panels.
For the crew, ISS is providing a living and working space larger than a six-bedroom house. The living space is divided into six sleeping quarters, two bathrooms, a gym and a 360-degree view bay window.
All the interior space of the station - 13,696 cubic feet (388 cubic meters) habitable volume, 32,333 cubic feet (916 cubic meters) pressurized volume - has been achieved by linking together a number of cylinders called modules.
Power for the station comes from the 8 solar arrays that provide 75 to 90 kilowatts of power. They are mounted on the station’s backbone called truss, a structure 357.5 feet (109 meters) in length. The solar panels, 239.4 feet (73 meters) long, are the ones that give the station a distinctive look when seen from Earth.
The ISS comprises some pressurized modules which serve as a habitat for its crew and provide ports for docking and berthing of visiting vehicles. Being an international effort, several of the countries involved in the project developed they own modules.
The large modules and other pieces of the station were delivered on 42 assembly flights, 37 with the U.S. space shuttles and five wth Russian Proton/Soyuz rockets.
IMPORTANT MODULESNode 1 Unity is the first U.S.-built element that was launched to the ISS. It was developed by Boeing, and It is currently used to connect the Russian and American parts of the station.
Node 2 Harmony is the work of Thales Alenia Space Italy and was built in Europe. It provides crew quarters for 4 members as well as vital functional resources for the operation of the connected elements: the conversion and distribution of the electrical power, heating, cooling and support of data and video exchange with the ground and the rest of the ISS.
Node 3 Tranquility has also been designed in Europe. It houses equipment for air revitalization, oxygen generation, carbon dioxide removal and water recovery systems. The bathroom for the crew and exercising equipment can also be found here.
When astronauts decided to go out for a spacewalk, be it in the American or Russian made spacesuits, they use the Joint Airlock Quest module, a unit also developed by Boeing. Since 1998, astronauts and cosmonauts have conducted more than 205 spacewalks for station construction, maintenance, and repair, most of the spacewalks originating from here.
The Functional Cargo Block Zarya is a module created by the Russian Khrunichev State Research and Production Space Center. It was Russia’s first module launched to the ISS and is a self-contained module offering power, communications, and attitude control functions.
When supplies and astronauts reach the space station in the Soyuz and Progress vehicles, they use the Docking Compartment Pirs module built by Russian S.P. Korolev Rocket and Space Corporation Energia.
Service Module Zvezda is a Russian contribution offering living quarters, life-support system, electrical power distribution, data processing system, flight control system, and propulsion system.
RESEARCHIn all, more than 20 different research payloads can be housed outside the station at once, including Earth sensing equipment, materials science payloads, or particle physics experiments.
Several research facilities are in place aboard the ISS to support microgravity science investigations, including in biology, biotechnology, human physiology, material science, physical sciences, and technology development.
Since its creation, the space station conducted over 2,400 research investigations from researchers in more than 103 countries.
At the following link you can find NASA’s Reference Guide to the International Space Station.