Two satellites collide in orbit



In an unprecedented space collision, a commercial Iridium communications satellite and a presumably defunct Russian Cosmos satellite ran into each other Tuesday above northern Siberia, creating a cloud of wreckage, officials said today.


An artist's concept of an Iridium satellite orbiting the Earth. Photo: Iridium


The international space station does not appear to be threatened by the debris, they said, but it's not yet clear whether it poses a risk to any other military or civilian satellites.

"They collided at an altitude of 790 kilometers (491 miles) over northern Siberia Tuesday about noon Washington time," said Nicholas Johnson, NASA's chief scientist for orbital debris at the Johnson Space Center in Houston. "The U.S. space surveillance network detected a large number of debris from both objects."

One source said nearly 300 fragments were being tracked, but Johnson said it was not yet clear how much debris was generated.

"It's going to take a while," he said. "It's very, very difficult to discriminate all those objects when they're really close together. And so, over the next couple of days, we'll have a much better understanding. But it's at a minimum, I think we're talking many, many dozens, if not hundreds."

Asked which satellite was at fault, Johnson said "they ran into each other. Nothing has the right of way up there. We don't have an air traffic controller in space. There is no universal way of knowing what's coming in your direction."

Iridium Satellite LLC operates a constellation of some 66 satellites, along with orbital spares, to support satellite telephone operations around the world. The spacecraft, which weigh about 1,485 pounds when fully fueled, are in orbits tilted 86.4 degrees to the equator at an altitude of about 485 miles. Ninety-five Iridium satellites were launched between 1997 and 2002 and several have failed over the years.

"Yesterday, Iridium Satellite LLC lost an operational satellite," the company said in a statement. "According to information shared with the company by various U.S. government organizations that monitor satellites and other space objects (such as debris), it appears that the satellite loss is the result of a collision with a non-operational Russian satellite.