[amsat-bb] Scratch two sats

[Andrew Glasbrenner]

http://news.yahoo.com/s/ap/20090211/ap_on_sc/satellite_collision

Iridium versus a Russian satellite, I wonder who'll get the ticket.

73, Drew

CAPE CANAVERAL, Fla. - Two big communications satellites collided in the 
first-ever crash of two intact spacecraft in orbit, shooting out a pair of 
massive debris clouds and posing a slight risk to the international space 
station.

NASA said it will take weeks to determine the full magnitude of the crash, 
which occurred nearly 500 miles over Siberia on Tuesday.

"We knew this was going to happen eventually," said Mark Matney, an orbital 
debris scientist at Johnson Space Center in Houston.

NASA believes any risk to the space station and its three astronauts is low. 
It orbits about 270 miles below the collision course. There also should be 
no danger to the space shuttle set to launch with seven astronauts on Feb. 
22, officials said, but that will be re-evaluated in the coming days.

The collision involved an Iridium commercial satellite, which was launched 
in 1997, and a Russian satellite launched in 1993 and believed to be 
nonfunctioning. The Russian satellite was out of control, Matney said.

The Iridium craft weighed 1,235 pounds, and the Russian craft nearly a ton.

No one has any idea yet how many pieces were generated or how big they might 
be.

"Right now, they're definitely counting dozens," Matney said. "I would 
suspect that they'll be counting hundreds when the counting is done."

As for pieces the size of micrometers, the count will likely be in the 
thousands, he added.

There have been four other cases in which space objects have collided 
accidentally in orbit, NASA said. But those were considered minor and 
involved parts of spent rockets or small satellites.

Nicholas Johnson, an orbital debris expert at the Houston space center, said 
the risk of damage from Tuesday's collision is greater for the Hubble Space 
Telescope and Earth-observing satellites, which are in higher orbit and 
nearer the debris field.

At the beginning of this year there were roughly 17,000 pieces of manmade 
debris orbiting Earth, Johnson said. The items, at least 4 inches in size, 
are being tracked by the U.S. Space Surveillance Network, which is operated 
by the military. The network detected the two debris clouds created Tuesday.

Litter in orbit has increased in recent years, in part because of the 
deliberate breakups of old satellites. It's gotten so bad that orbital 
debris is now the biggest threat to a space shuttle in flight, surpassing 
the dangers of liftoff and return to Earth. NASA is in regular touch with 
the Space Surveillance Network, to keep the space station a safe distance 
from any encroaching objects, and shuttles, too, when they're flying.

"The collisions are going to be becoming more and more important in the 
coming decades," Matney said.

Iridium Holdings LLC has a system of 65 active satellites which relay calls 
from portable phones that are about twice the size of a regular mobile 
phone. It has more than 300,000 subscribers. The U.S. Department of Defense 
is one of its largest customers.

The company has spare satellites, and it is unclear whether the collision 
caused an outage. An Iridium spokeswoman had no immediate comment.

Initially launched by Motorola Inc. in the 1990s, Iridium plunged into 
bankruptcy in 1999. Private investors relaunched service in 2001.

Iridium satellites are unusual because their orbit is so low and they move 
so fast. Most communications satellites are in much higher orbits and don't 
move relative to each other, which means collisions are rare.

Iridium Holdings LLC, is owned by New York-based investment firm Greenhill & 
Co. through a subsidiary, GHL Acquisition Corp., which is listed on the 
American Stock Exchange. The shares closed Wednesday down 3 cents at $9.28.

___

AP science writer Seth Borenstein in Washington and AP technology writer 
Peter Svensson in New York contributed to this report.