Crash imperils satellites that monitor Earth
WASHINGTON - Shrapnel from the collision of a Russian and an American communications satellite -- the first time in history that two intact spacecraft have hit each other -- threatens several Earth observation satellites that orbit about 50 miles below where the two probes hit, NASA officials said Thursday.
"This is a major one," said Nick Johnson, who leads NASA's effort to monitor space junk. He said that the collision -- 490 miles above Siberia -- may generate more debris than any event in space history, including China's controversial destruction of an orbiting satellite in 2007.
"We see lots of pieces," he said.
NASA scientists had few details Thursday about debris that scattered when a U.S. satellite owned by Iridium Corp. hit an out-of control Russian probe in what amounted to a 26,000 mph collision.
They said there was no immediate risk to the international space station and its crew of three -- which orbits about 270 miles below the collision -- or to an upcoming shuttle launch to the station. The Hubble Space Telescope, which orbits about 160 miles higher than the space station, is also not considered at risk, NASA officials added.
Level of risk unknown
Right now, they're most worried that orbiting wreckage from the crash could damage or destroy a nearby flock of five satellites, called the A-Train, which monitor Earth's climate.
"The risk is increased. I can't tell you the magnitude of that risk, whether it went up 1 percent, 5 percent or 10 percent. We don't have a lot of information yet to quantify," Johnson said. More answers should be coming in the next few days, he said.
NASA launched the first A-Train satellite in 2002 and since has added four more probes to the close-flying formation, which measures a wide range of data, from radiation to rainfall. A sixth satellite, the Orbiting Carbon Observatory, is scheduled to join the group this month to help track carbon dioxide.
Previously, China held the record for generating the most space junk when it launched a missile to destroy one of its own weather probes during an anti-satellite test. That blast created at least 2,500 pieces larger than 4 inches, the size that can be tracked by NASA and the Defense Department.
The latest collision has the potential to be far worse. During the Chinese test, the ballistic weapon used to destroy the satellite fell immediately back to Earth -- leaving no debris. All that remained were the shattered pieces of the weather satellite, Johnson said.
But this time, hundreds or thousands of pieces of both satellites -- each satellite the size of a car, weighing a combined total of more than 3,200 pounds -- remain in orbit.
In the past, NASA has been able to move satellites and the space station out of the way when they are threatened by trackable pieces of orbital debris. For instance, NASA has taken five evasive maneuvers with the A-Train since 2005, said NASA spokesman Steve Cole.
The real concern is with pieces smaller than 4 inches, which astronomers cannot track and thus cannot program spacecraft to avoid. Even something the size of a marble can pierce most spacecraft armor.
This collision adds to a growing ring of space junk circling the Earth. At last estimate, there were about 17,000 pieces bigger than a grapefruit, and tens of millions more that are smaller.
Why didn't probe move?
Ironically, one of the satellites involved in the crash -- launched in 1997 by Maryland-based Iridium, which serves satellite phones -- had the ability to move out of the way of the Russian probe. Launched in 1993, it was dead and could not move.
An Iridium spokeswoman had no explanation for why the company did not try an evasive maneuver, other than "it is impossible for any organization to see everything that's happening in space at all places at all times."
Spokeswoman Liz DeCastro would not comment on whether Iridium might take legal action but said that the company would move a spare satellite to replace the wrecked one. It now has 65 satellites, plus eight spares, in orbit.
Iridium customers can expect to experience a few minutes without service for now because of the missing satellite.
Mark K. Matthews can be reached at email@example.com or 202-824-8222.
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