US, Russian satellites collide in space

12th February 2009, Comments 0 comments

US and Russian communications satellites collided in space in the first such reported accident, producing massive clouds of debris that is expected to linger for weeks.

WASHINGTON – US and Russian satellites have collided in the first known major space accident of its kind, creating two clouds of debris that were being tracked by experts on Thursday.

A communications satellite belonging to US company Iridium hit a disused Russian military satellite on Tuesday, officials said.

According to US space agency NASA, there is a small risk that the orbiting International Space Station could hit one of two clouds of debris.

The collision took place 800 kilometres (500 miles) above the Earth, Russia's Interfax news agency quoted the head of the country's space forces as saying.

"A collision occurred between an Iridium 33 satellite and a Russian Kosmos 2251 military satellite," Major General Alexander Yakushin said.

The Russian satellite was launched in 1993 and ceased to function two years later, he added.

NASA was tracking hundreds of particles of debris from the collision, and said the orbiting International Space Station faced a small risk of being struck.

"While this is an extremely unusual, very low-probability event, the Iridium constellation is uniquely designed to withstand such an event, and the company is taking the necessary steps to replace the lost satellite with one of its in-orbit spare satellites," the Iridium Satellite company said in a statement.

Iridium Satellite, which says its network comprises 66 communication satellites plus in-orbit spares, rejected any fault for the accident.

"This satellite loss may result in very limited service disruption in the form of brief, occasional outages," it said, adding that the company expects to implement a solution by Friday, and move one a spare satellite already in orbit to replace the destroyed satellite within 30 days.

According to Space News, NASA issued an alert Tuesday saying the 900 kilogram (1,980 pound) Russian Cosmos 2251 satellite collided with Iridium's 560-kilogram (1,232-pound) craft at 16:55 GMT, some 790 kilometres (490 miles) above Siberia.

It said NASA was tracking two large clouds of debris.

Will the debris pose risk to the ISS?
The Washington Post quoted a NASA memo saying officials "have determined that the risk to the space station is elevated, and they estimate the risk to be very small and within acceptable limits."

There is small risk the space station will enter the debris clouds, however, as the ISS is orbiting about 354 kilometres (220 miles) above Earth, some 436 kilometres (270 miles) below the collision orbit.

Cosmic collisions of space junk are not unheard of, but NASA officials said it was the first involving two intact satellites, the Post reported.

NASA spokesman John Yembrick said the collision debris would continue to spread and could end up forcing the space station into evasive manoeuvres.

"The space station does have the capability of doing a debris-avoidance manoeuvre if necessary," and has done so on eight occasions, he said.

Some 6,000 satellites have been sent into space since the Soviet Union launched the first man-made orbiter, Sputnik 1, in 1957. About 3,000 satellites remain in operation, according to NASA.

NASA's space shuttle Discovery is to launch from Florida's Kennedy Space Centre on February 22 at the earliest, on a mission to the ISS.

[AFP / Expatica]

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