By SETH BORENSTEIN and DOUGLAS BIRCH
MOSCOW (AP) — U.S. and Russian officials traded shots Thursday over
who was to blame for a huge satellite collision this week that spewed
speeding clouds of debris into space, threatening other unmanned
spacecraft in nearby orbits.
The smashup 500 miles (800
kilometers) over Siberia on Tuesday involved a derelict Russian
spacecraft designed for military communications and a working satellite
owned by U.S.-based Iridium, which served commercial customers as well
as the U.S. Department of Defense.
A prominent Russian space
expert suggested NASA fell down on the job by not warning of the
collision. But U.S. space experts said the Russian has the wrong agency.
U.S. military tracks the 18,000 objects in orbit, monitoring only
certain threats because it lacks the resources to do everything, said
Maj. Regina Winchester, spokeswoman for U.S. Strategic Command, which
oversees the military's Space Surveillance Network.
spokeswoman Elizabeth Mailander said the company can move any of its 65
satellites out of the way if it gets a precise warning ahead of a
crash. Such a warning was not made Tuesday, Mailander said.
the company has never redirected a satellite before because the
warnings they get aren't precise enough and there are just too many
satellites to be constantly rejiggering their orbit, she said.
was where it was supposed to be and it was functioning," Mailander
said. She said Iridium hasn't talked with Russian space officials.
one has any idea yet how many pieces of space junk were generated by
the collision or how big they might be. But the crash scattered space
junk in orbits 300 to 800 miles (500 to 1,300 kilometers) above Earth,
according to Maj.-Gen. Alexander Yakushin, chief of staff for the
Russian military's Space Forces.
Experts in space debris will
meet next week in Vienna at a U.N. seminar to come up with better ways
to prevent future crashes, said NASA orbital debris program manager
Igor Lisov, a prominent Russian space expert,
said Thursday he did not understand why NASA's debris experts and
Iridium had failed to prevent the collision, since the Iridium
satellite was active and its orbit could be adjusted.
have been a computer failure or a human error," he said. "It also could
be that they only were paying attention to smaller debris and ignoring
the defunct satellites."
But that job belongs to the U.S. Department of Defense's Space Surveillance Network, which was created with NASA's help.
network's top priority is protecting astronauts — warning if there is a
threat to the international space station or manned spacecraft. And it
gives NASA precise warnings for about a dozen satellites that could be
maneuvered out of the way, something that happens once in a while,
There are 800 to 1,000 active satellites in orbit
and about 17,000 pieces of debris and dead satellites, like the Russian
one, that can't be controlled, he said. The U.S. space tracking network
doesn't have the resources to warn all satellite operators of every
possible close call, Johnson and Winchester said.
"It's unfortunate that we cannot predict all of the collisions all of the time," said Winchester.
private Web site, named Socrates, does give daily risk of crash
warnings for satellites and Iridium, with 65 satellites, frequently is
in the top 10 daily risks, Johnson said. However, the Iridium satellite
wasn't on Tuesday's warning list, he said.
Lisov said the debris may threaten a large number of earth-tracking and weather satellites in similar orbits.
is a quite a lot of satellites in nearby orbits," he told The
Associated Press. "The other 65 Iridium satellites in similar orbits
will face the most serious risk, and there numerous earth-tracking and
weather satellites in nearby orbits. Fragments may trigger a chain of
Both the U.S. surveillance network and Russian Space
Forces are tracking the debris, believed to be traveling at speeds of
around 200 meters — or about 660 feet — per second.
NASA said it
would take weeks to know the full magnitude of the crash, but both NASA
and Russia's Roscosmos agencies said there was little risk to the
international space station and its three crew members.
Russian Mission Control spokesman Valery Lyndin noted the station's orbit has been adjusted in the past to dodge space debris.
space junk also is unlikely to pose a threat to the space shuttle set
to launch Feb. 22 with seven astronauts, U.S. officials said, although
that issue will be reviewed.
The Iridium orbiter weighed 1,235
pounds (560 kilograms), and the decommissioned Kosmos-2251 military
communications craft weighed nearly a ton. The Kosmos was launched in
1993 and went out of service two years later in 1995, Yakushin said.
Soviet-built, nuclear-powered satellites long out of action in higher
orbits may also be vulnerable to collisions, Lisov said. If one of them
collides with the debris, the radioactive fallout would pose no threat
to Earth, he said, but its speeding wreckage could multiply the hazard
to other satellites.
Iridium said the loss of the satellite was
causing brief, occasional outages in its service and it expected to fix
the problem by Friday. The Bethesda, Maryland-based company said it
expected to replace the lost satellite with one of its eight in-orbit
spares within 30 days.
The replacement cost for an Iridium
satellite is between $50 million and $100 million, including the
launch, said John Higginbotham, chief executive of Integral Systems
Inc., which runs ground support systems for satellites.
AP Writer Vladimir Isachenkov in Moscow and AP Technology Writer
Peter Svensson in New York contributed to this report. AP Science
Writer Seth Borenstein contributed from Washington.