The recent surge in space junk created by an
accidental satellite collision last month has bumped up the upcoming space
shuttle mission's chances of taking a catastrophic hit, NASA officials said.
However, the likelihood of the shuttle intercepting debris is still so low that
mission managers don't foresee any problems.
Engineers analyzed how much danger would be posed to the
shuttle Discovery's upcoming STS-119 flight, scheduled to launch March 11, by
the new debris, which was created when a U.S. and a Russian communication
satellite unexpectedly rammed
into each other in orbit. The Feb. 10
smash-up produced two large clouds of shrapnel that are now circling the
Earth, NASA said.
The investigation found that the new
space junk raises Discovery's risk factor by 6 percent, giving it a chance
of about 1 in 318 of being fatally hit by debris. Mission managers had estimated a similar figure shortly after the satellite collision, but said they had reviewed the risk in detail today.
"That is very comparable to almost all of
the 14-day missions we fly," said John Shannon, NASA space shuttle program
manager, at a briefing today.
The collision occurred about 490 miles (790 km) over
Siberia. Discovery is due to fly up to 220 miles (354 km) above Earth, where it
will dock with the International Space Station to deliver new solar array
wings.
NASA is still assessing the risk to the upcoming Hubble
repair space shuttle mission, targeted to fly in late May. The danger to this
trip could be greater, managers said, because that shuttle is set to take its
crew to an altitude of about 372 miles (600 km), putting it much closer to the
range of the collision than the space station is.
"That didn't look so good, when they looked at
that," Bill Gerstenmaier, NASA's space operations chief, has said.
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