Whiteangel33

The International Space Station (ISS) is an internationally developed research facility that is being assembled in low Earth orbit. On-orbit construction of the station began in 1998 and is scheduled for completion by 2011. The station is expected to remain in operation until at least 2015, and likely 2020. With a greater mass than that of any previous space station, the ISS can be seen from the Earth with the naked eye, and, as of 2010, is the largest artificial satellite orbiting the Earth. The ISS serves as a research laboratory that has a microgravity environment in which crews conduct experiments in biology, human biology, physics, astronomy and meteorology. The station has a unique environment for the testing of the spacecraft systems that will be required for missions to the Moon and Mars. The ISS is operated by Expedition crews, and has been continuously staffed since 2 November 2000, meaning the ISS programme has maintained an uninterrupted human presence in space for the past & 9 years and 159 days, which is approaching the current record, set aboard Mir, of 9 years and 257 days. As of 18 March 2010, the crew of Expedition 23 is aboard.

The ISS provides a location in the relative safety of Low Earth Orbit to test spacecraft systems that will be required for long-duration missions to the Moon and Mars.

Because of the size of the ISS (about that of an American football field) and the large reflective area offered by its solar panels, ground based observation of the station is possible with the naked eye if the observer is in the right location at the right time. In many cases, the station is one of the brightest naked-eye objects in the sky, although it is visible only for periods ranging from two to five minutes.

The cost estimates for the ISS range from 35 billion to 160 billion dollars.