Satellites from Russia and America have collided around 500 miles above Siberia. The crash has caused what NASA has called a small but elevated risk of debris hitting the International Space Station.

While pieces of space junk have collided before, this is the first time two entire satellites have collided. It appears both satellites were destroyed in the crash. Nasa’s Nicholas Johnson says there’s no way to apportion blame for the incident: “Nothing has the right of way up there. We don’t have an air traffic controller in space.”

The Russian satellite was launched in 1993 but has been non-operational for at least ten years. The US satellite, launched in 1997, belonged to Maryland company Iridium which runs a network of 66 satellites, the largest commercial set-up worldwide. It hopes to have a spare satellite, already in orbit, operational within 30 days.

The collision has produced an estimated 600 pieces of debris. A Nasa memo says there is a risk of this debris hitting the International Space Station, but classes the risk as “very small and within acceptable limits.” That’s because the ISS orbits much lower than the two satellites. Were any of the debris to fall low enough to cause problems, there is a procedure to reroute the ISS.

There are hundreds of satellites, including 20 belonging to Nasa, which orbit at the same height as those which collided. However, the comparatively small size of the satellites used at this height, many designed for weather monitoring, means there’s less risk of being hit by debris. The value of the ISS makes it Nasa’s priority in monitoring and preventing further collision.

The incident highlights the growing mechanical presence in space. There are around 6,000 satellites in orbit, half of which are no longer used. And there are an estimated 17,000 pieces of debris from man-made objects, some as small as 10 cm across.

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Entry was posted on Thursday, February 12th, 2009 at 12:21 pm under Technology.

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