[meteorite-list] Scratch one set of Iridium flares

From: Darren Garrison <cynapse_at_meteoritecentral.com>
Date: Wed, 11 Feb 2009 21:19:20 -0500
Message-ID: <gn17p41arfnfu6hlh19no3s2b727g852ov_at_4ax.com>

http://www.nytimes.com/2009/02/12/science/space/12satellite.html?hp

Debris Spews Into Space in Collision of Satellites

By WILLIAM J. BROAD
Published: February 11, 2009

For decades, space experts have warned of orbits around the planet growing so
crowded that two satellites might one day slam into one another, producing
swarms of treacherous debris.

It happened Tuesday. And the whirling fragments could pose a threat to the
International Space Station, orbiting 215 miles up with three astronauts on
board, though officials said the risk was now small.

?This is a first, unfortunately,? Nicholas L. Johnson, chief scientist for
orbital debris at the National Aeronautics and Space Administration, said of the
collision.

It happened some 490 miles above northern Siberia, at around noon Eastern time.
Two communications satellites ? one Russian, one American ? cracked up in silent
destruction. In the aftermath, military radars on the ground tracked large
amounts of debris going into higher and lower orbits.

?Nothing to this extent? has ever happened before, Mr. Johnson said. ?We?ve had
three other accidental collisions between what we call catalog objects, but they
were all much smaller than this,? the objects always very small and moderate in
size.

The communication satellites, he added, ?are two relatively big objects.?

The American satellite was an Iridium, one of a constellation of 66 spacecraft.
Liz DeCastro, corporate communications director of Iridium Satellite, based in
Bethesda, Md., said that the satellite weighed about 1,200 pounds and that its
body was more than 12 feet long, not including large solar arrays.

In a statement, the company said that it had ?lost an operational satellite? on
Tuesday, apparently after it collided with ?a nonoperational? Russian satellite.

?Although this event has minimal impact on Iridium?s service,? the statement
added, ?the company is taking immediate action to address the loss.? The
company?s hand-held phones can be used anywhere around the globe to give users
voice and data communications.

Mr. Johnson said the Russian satellite was presumably nonfunctional. Officials
at the Russian Embassy in Washington could not be reached for comment.

Mr. Johnson said the United States military?s tracking radars had yet to
determine the number of detectable fragments. ?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.?

At a minimum, Mr. Johnson added, ?I think we?re talking many, many dozens, if
not hundreds.?

The debris could threaten the space station and its astronaut crew, he said.

?There are actually debris from this event which we believe are going through
space station altitude already,? he said. The risk to the station, Mr. Johnson
added, ?is going to be very, very small.? In the worst case, he said, ?We?ll
just dodge them if we have to. It?s the small things you can?t see that are the
ones that can do you harm.?

In Houston, International Space Station controllers have often adjusted its
orbit to get out of the way of speeding space debris, which can move so
incredibly fast that even small pieces pack a destructive wallop.

John Yembrick, a NASA spokesman in Washington, said the agency now judged the
risk of collision with the speeding fragments to be ?very small.? The threat, he
added, is defined and acceptable.

Mr. Johnson, who works at the Johnson Space Center in Houston, said the new
swarms of whirling debris might also eventually pose a threat to other
satellites in an orbital chain reaction.

?What we?re doing now is trying to quantify that risk,? he said. ?That?s a work
in progress. It?s only been 24 hours. We put first things first,? meaning the
station and preparing for the next shuttle mission.

William Harwood contributed reporting.
Received on Wed 11 Feb 2009 09:19:20 PM PST