Two satellites collide 500 miles over Siberia

Two communications satellites collided Tuesday in an unprecedented
orbital accident that would have been visible from the Earth, a NASA
scientist said Wednesday.
The collision roughly 500 miles from Earth created a huge field of
debris, but the risk to the International Space Station and its crew
of three — 215 miles from Earth — is very low, said Nicholas Johnson
of NASA's Johnson Space Center. So is the risk to the next shuttle
mission, he said. The launch is scheduled for as early as Feb. 22.

The debris, though, could make it more dangerous for astronauts to
repair the Hubble Space Telescope on a space shuttle mission planned
for May, Johnson said. The Hubble is about 375 miles from Earth,
Johnson said, and debris generally falls toward Earth.

The collision was between a now-defunct Russian communications
satellite launched in 1993 and one of 66 satellites privately owned by
Iridium, a Maryland company that provides phone service to customers
such as workers on offshore oil platforms. The company said in a
statement that service interruptions should be minimal and fixed by
Friday.

The collision, which occurred at about noon ET Tuesday, "was dramatic,
and it has significant consequences for the (space) environment,"
Johnson said. "This was the worst such incident that's ever occurred."

The spacecraft collided over northern Siberia, where it was evening at
the time. A "flash" would have been visible from the ground, Johnson
said.

The hundreds, if not thousands, of pieces of debris created by the
collision could damage other working satellites, he said. Especially
at risk are other Iridium satellites, which are "right there in the
heart of the cloud."

Although the U.S. military and others track orbital objects, there is
no way to prevent them from running into each other. Such collisions
are rare, however.

"Space is a big place. The odds are very small that something like
this would happen," Johnson said.

"There are no rules of the road in space," he said. "Anyone can be
anywhere they want to be."

The incident was first reported by the website Spaceflight Now.

The worst debris cloud in space was created in 2007 when China
deliberately shot a missile at an old satellite, which shattered into
thousands of pieces. This collision could have created just as much
debris, but scientists need to study it, Johnson said.

Johnson said that on Tuesday, he had checked a public website listing
the day's 10 most likely collisions in space. The Iridium-Russian
satellite pairing was not on it. "It should've been No. 1, in
retrospect," he said.