The International Space Station is an orbiting laboratory and construction site that synthesizes the scientific expertise of 16 nations to maintain a permanent human outpost in space. While floating some 240 miles (390 kilometers) above Earth's surface, the space station has hosted a rotating international crew since November 2000. Astronauts and supplies are ferried by the U.S. space shuttles and the Russian Soyuz and Progress spacecraft. Astronauts who reach the facility aboard one of these missions typically live and work in orbit for about six months.

Simply by spending time in orbit, astronauts reveal much more about how humans can live and work in space. Crews have learned the difficulties of diet, in a world in which their sense of taste is decreased, and of getting a good night's sleep while secured to a non-floating object.

But the crew is also occupied with a full suite of scientific experiments, the ongoing improvement and construction of the station, and a rigorous regime of physical training. Astronauts must exercise for two hours each day to counteract the detrimental effects of low gravity on the body's skeleton and circulatory system.

Ongoing Construction
The station has been under construction since November of 1998. In that year the first piece of its structure, the Zarya Control Module, was launched into orbit with a Russian Proton rocket. In 2008, the two-billion-dollar science lab Columbus was added to the station, increasing the structure to eight rooms.

The floating facility's design features a series of cylinder modules attached to a larger truss of a dozen segments. The Zarya Module is mainly used for storage and external fuel tanks, while the Zvezda Service Module houses the crew's living quarters and the station's many life-supporting systems. The space station is powered by solar panels and cooled by loops that radiate heat away from the modules. The station's Destiny laboratory functions as a unique floating facility for tests of materials, technologies, and much more. The Columbus lab was designed to house experiments in life sciences, fluid physics, and other fields.

Docking ports allow the station to be visited by a growing variety of spacecraft, and the Quest Airlock enables access for the frequent spacewalks essential to the facility's continuing construction.

Canadarm2 is another important feature of the space station. This Canadian-built apparatus is a large, remote-controlled space arm that functions as a crane and can be utilized for a wide variety of tasks.

The International Space Station may be completed by the end of this decade. When construction is finished, six crew members will be able to live and work in a space larger than a typical five-bedroom house.

The International Space Station (ISS) is the most complex international scientific and engineering project in history and the largest structure humans have ever put into space. This high-flying satellite is a laboratory for new technologies and an observation platform for astronomical, environmental and geological research. As a permanently occupied outpost in outer space, it serves as a stepping stone for further space exploration.

The station flies at an average altitude of 248 miles (400 kilometers) above Earth. It circles the globe every 90 minutes at a speed of about 17,500 miles per hour (28,000 kph). In one day, the station travels about the distance it would take to go from Earth to the moon and back.

Five different space agencies representing 15 countries built the $100 billion International Space Station and continue to operate it today. NASA, Russia's Federal Space Agency, the European Space Agency, the Canadian Space Agency and the Japan Aerospace Exploration Agency are the primary space agency partners on the project.

The International Space Station was taken into space piece-by-piece and gradually built in orbit. It consists of modules and connecting nodes that contain living quarters and laboratories, as well as exterior trusses that provide structural support, and solar panels that provide power. The first module, Russia's Zarya module, launched in 1998. The station has been continuously occupied since November 2, 2000. The space station is planned to be operated through at least 2020.

During the space station's major construction phase, some Russian modules and docking ports were launched directly to the orbiting lab, while other NASA and international components (including Russian hardware) were delivered on U.S. space shuttles.

The space station, including its large solar arrays, spans the area of a U.S. football field, including the end zones, and weighs 861,804 pounds (391,000 kilograms), not including visiting vehicles. The complex now has more livable room than a conventional five-bedroom house, and has two bathrooms, a gymnasium and a 360-degree bay window. Astronauts have also compared the space station's living space to the cabin of a Boeing 747 jumbo jet.

The space station is so large that it can be seen from Earth without the use of a telescope by night sky.

Crew Size
A six-person expedition crew typically stays four to six months aboard the ISS. The first space station crews were three-person teams, though after the tragic Columbia shuttle disaster the crew size temporarily dropped to two-person teams. The space station reached its full six-person crew size in 2009 as new modules, laboratories and facilities were brought online.

If the crew needs to evacuate the station, they can return to Earth aboard two Russian Soyuz vehicles docked to the ISS. Additional crewmembers are transported to the ISS by Soyuz. Prior to the retirement of NASA's space shuttle fleet in 2011, new space station crewmembers were also ferried to and from the station during shuttle missions.

Crews aboard the ISS are assisted by mission control centres in Houston and Moscow and a payload control centre in Huntsville, Ala. Other international mission control centres support the space station from Japan, Canada and Europe. The ISS can be controlled from mission control centre in Houston or Moscow.

-The ISS solar array surface area could cover the U.S. Senate Chamber three times over.
-ISS eventually will be larger than a five-bedroom house.
-ISS will have an internal pressurized volume of 33,023 cubic feet, or equal that of a Boeing 747.
-The solar array wingspan (240 feet / 73 meters) is longer than that of a Boeing 777 200/300 model, which is 212 feet (64.6 m).
-Fifty-two computers will control the systems on the ISS.
-More than 115 space flights will have been conducted on five different types of launch vehicles over the course of the station’s construction.
-More than 100 telephone-booth sized rack facilities can be in the ISS for operating the spacecraft systems and research experiments
-The ISS is almost four times as large as the Russian space station Mir, and about five times as large as the U.S. Skylab.
-The ISS will weigh almost one million pounds (925,627 pounds / 419,857 kilograms). That’s the equivalent of more than 320 automobiles.
-The ISS measures 357 feet (108 meters) end-to-end. That’s nearly the length of a football field including the end zones.
-3.3 million lines of software code on the ground supports 1.8 million lines of flight software code.
8 miles (12.8 kilometers) of wire connects the electrical power system.
-In the International Space Station’s U.S. segment alone, 1.5 million lines of flight software code will run on 44 computers communicating via 100 data networks transferring 400,000 signals (e.g. pressure or temperature measurements, valve positions, etc.).
-The ISS will manage 20 times as many signals as the Space Shuttle.
-Main U.S. control computers have 1.5 gigabytes of total main hard drive storage in U.S. segment compared to modern PCs, which have about 500-gigabyte hard drives.
-The entire 55-foot robot arm assembly is capable of lifting 220,000 pounds, which is the weight of a Space Shuttle orbiter.
-The 75 to 90 kilowatts of power for the ISS is supplied by an acre of solar panels.