About ISS

What is this international space station anyway? Read all about its size, cost and inhabitants.

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What is ISS?

ISS, the International Space Station, is the largest Earth-orbiting research laboratory ever built. It circles the Earth every 91 minutes at an altitude of approximately 350 kilometers.


Who built ISS?

ISS is a joint project of the U.S. space agency NASA, the Russian space agency RKA, the European space agency ESA, the Japanese space agency JAXA and the Canadian space agency CSA.


When was ISS launched?

The first modules of ISS were launched in 1988. Ever since, ISS has been expanded with additional modules, laboratories, docking units, and huge solar panels. Construction is expected to be completed in 2011.


How big is ISS?

ISS measures 73 by 108.5 meters. When fully completed, it will consist of fourteen pressurized modules with a combined volume of about 1,000 cubic metres. The total living volume is 358 cubic meters. ISS has a total mass of just over 300 metric tons.


How many astronauts live and work in ISS?

ISS has been permanently manned since 2 November 2000. For the first nine years, ISS crews consisted of three astronauts. As of May 2009, the crew size will be double to six astronauts. During space shuttle visits, ten astronauts may live and work in ISS for a few days.


How long do astronauts stay at ISS?

Although many astronauts (and a few space tourists) have paid shorter visits to ISS, the normal duration of an ISS Expedition is six months.


How do astronauts travel to and from ISS?

Manned spaceflights to and from ISS can be carried out by NASA's space shuttle and by Russian Soyuz spacecraft. Since the shuttle is expected to be retired by late 2010 or early 2011, all astronauts, including American ones, will rely on Soyuz spacecraft for at least a number of years, until NASA's new Orion spacecraft becomes available.


What kind of science is being carried out at ISS?

Because of the microgravity conditions ('weightlessness') on board ISS, the laboratory is useful for a wide variety of scientific studies that can't be carried out on Earth, like certain material sciences (including the production of special crystals and proteins) and physiological sciences (how do living organisms, including humans, respond to microgravity).


How long will ISS be operational?

At least until 2015. NASA is still considering an extended operational lifetime, maybe until 2025 or beyond.


How expensive is ISS?

It's hard to say, because it's not always clear which costs should be included and which shouldn't. Estimates for the total costs of ISS over a period of 30 years range from 35 to 100 billion dollars.