Defunct Cosmos Probe, Iridium Satellite 'Ran Into Each Other'

On Tuesday, a defunct Russian military satellite collided with an active Iridium communication satellite in orbit, about 490 miles above northern Siberia... in what is believed to be the first documented case of an accidental satellite collision.

Nicholas Johnson, the chief scientist for orbital debris at NASA's Johnson Space Center in Houston, told CBS News surveillance networks are tracking a large cloud of debris from the impact, and it's unclear whether those pieces may pose problems for other on-orbit satellites.

"As of about 12 hours ago, I think the head count was up (to around) 600 pieces," added Air Force Brig. Gen. Michael Carey, deputy director of global operations at US Strategic Command. "It's going to take about two days before we get a solid picture of what the debris fields look like. But you, I think, can imply that the majority of that should be probably along the same line as the original orbits."

Carey identified the Russian satellite as Cosmos 2251, a communications relay station launched in 1993 and believed to have been offline for around 10 years. "Nothing to this extent (has happened before)," he said. "We've had three other accidental collisions between what we call catalog objects, but they were all much smaller than this and always a moderate sized objects and a very small object. And these are two relatively big objects. So this is a first, unfortunately."

While NASA is fairly sure the International Space Station has little to fear from the collision, Johnson said it will take awhile to know what further dangers the debris may pose.

"There are two issues: the immediate threat and a longer-term threat," he said. "It turns out, when you have a collision like this the debris is thrown very energetically both to higher orbits and to lower orbits. So there are actually debris from this event which we believe are going through the space station's altitude already. Most of it is not, most of it is still clustered up where the event took place. But a small number are going through station's altitude," around 220 miles above Earth.

Iridium issued a terse statement Wednesday about the loss of one of its satellites, stressing the even had "minimal impact" on the company's service. "...The company is taking immediate action to address the loss," Iridium stated. "The Iridium constellation is healthy, and this event is not the result of a failure on the part of Iridium or its technology. 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 satellite telephone company has around 65 satellites in orbit, as well as several spares. Each is oriented at 86.4 degrees to the Equator, at about 485 miles above Earth's surface.

As for which satellite was to blame for the incident, Johnson took a diplomatic tact. "They ran into each other," he said. "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."

So long as the debris doesn't strike any other objects, most of it will burn up in the atmosphere.

FMI: www.iridium.com