International Space Station

Continuing on from the United States' Skylab and Russia's Mir, the International Space Station (ISS) represents a permanent human presence in space. The space station is located in orbit around the Earth at an altitude of approximately 386 km, a type of orbit usually termed low Earth orbit. (The actual height varies over time by several kilometres due to atmospheric drag and reboosts.)

It is serviced primarily by the Space Shuttle, and Soyuz and Progress spacecraft units. It is still being built, but is home to some experimentation already.

At present, the station has a crew of three, mostly from Russia and the United States, but occasionally from some of the other partners in the project.

The station consists of several modules:

• Zarya (launched November 20, 1998)
• Unity Module (launched December 4, 1998, also known as Node 1)
• Zvezda (launched July 12, 2000)
• Destiny Laboratory Module (launched February 7, 2001)
• Node 2 (under review)
• Columbus orbital facility (under review)
• Japanese Experiment Module (under review), also known as Kibo

Other major subsystems include

• a girder truss forming a structural backbone to the station
• solar panel arrays
• the Mobile Servicing System (Canadarm2)

The ISS has had a troubled history. Initially planned as a NASA "Space Station Freedom" and promoted by President Reagan, it was found to be too expensive. After the end of the Cold War, it was taken up again as a joint project of NASA and Russia's Rosaviakosmos. Since then, it has been far more expensive than originally anticipated by NASA, and is behind schedule. As of 2003 it is unable to yet accommodate the expected crew of six, thus severely limiting the amount of science that can be performed on it and angering European partners in the project.

There are many critics of NASA who view the project as a waste of time, inhibiting progress on more useful projects: for instance, the estimated $100 billion USD lifetime cost could pay for dozens of uncrewed scientific missions. There are many critics of space exploration in general, who argue that the $100 billion USD would be better spent helping the poor or improving the environment.

Advocates of space exploration hold that such criticisms are at the very least short-sighted, and perhaps deceptive. Advocates of crewed space research and exploration claim that these efforts have indeed produced billions of dollars of tangible benefits to people on Earth. In some estimates, it has been held that the indirect economic benefit, made from commercialization of crewed space exploration developed technologies, has returned more to the economy that was spent in the first place. Whether the ISS, as distinct from the wider space program, will be a major contributor in this sense is however a subject of strong debate.

International Space Station photographed from the Space Shuttle Atlantis, October 16, 2002

After the accident of the Space Shuttle Columbia on February 1, 2003, and the subsequent suspension of the US Space Shuttle program, the future of the ISS is uncertain. The construction is halted as that is done by the Space Shuttle, and the crew exchange is done using the russian Soyuz spacecraft. With Soyuz TMA-2 a two-astronaut caretaker crew is launched, instead of the previous crews of three.

External links

• International Space Station Official site
• Track the Space Station from your current location

Tangible benefits of research from the space station

• http://spd.nasa.gov/
• Spacelink - Space Product Development
• http://www.planetarysociety.org/
• http://www.seds.org/pub/seds/National/misc/why-space