Sue Hartigan <[EMAIL PROTECTED]> writes:
Meteor Storms Threaten Satellites
ASSOCIATED PRESS
MANHATTAN BEACH, Calif. (AP) -- In November, the
Earth's atmosphere will be hit with the most severe
meteor shower in 33 years, a bombardment of debris
that could damage or destroy some of the nearly 500
satellites that provide worldwide communications,
navigation and weather-watching.
The debris consists only of particles -- some thinner
than a hair and most no larger than a grain of sand --
but they are hurtling through space so fast that they
can
have the destructive power of a .22-caliber bullet.
As a result, about 200 commercial and military
satellite operators, insurers and scientists began
brainstorming here Monday about what they can do to
prepare, such as turn off spacecraft or turn them away
from the stream of particles. The two-day gathering is
called the Leonid Meteoroid Storm and Satellite
Threat Conference.
"The consequences are still virtually unknown. There
has not been a meteor storm since the onset of the
modern space age. Nobody planned for it," said Peter
Brown, a physics and astronomy graduate student at
the University of Western Ontario who advises satellite
operators.
The particles, known as meteoroids, are vastly smaller
than the asteroids that could one day slam into Earth,
and none are expected to come anywhere near the
surface of the planet when they strike this November
and again in November 1999.
But before the particles burn up in Earth's atmosphere,
they could poke holes in solar panels, pit lenses, blast
reflective coating off mirrors, short out electronics
with
a burst of electromagnetic energy, even reprogram
computers, said Edward Tagliaferri, a consultant to the
Aerospace Corp., a nonprofit organization.
In 1993, for example, a meteor struck the European
Space Agency's Olympus satellite and destroyed its
directional control, rendering it useless.
"What if you get unlucky?" Delbert Smith, a
Washington lawyer who represents international
networks and satellite operators, asked at the
conference. "Who's going to explain to the major
corporations your satellites aren't there anymore?"
While only a couple of satellites might get disabled --
and some cost as much as $500 million -- all of them
will suffer surface damage, said David Lynch, a
scientist with the Aerospace Corp.
Military satellites are better shielded because most
are built to withstand nuclear assault. But unlike
commercial spacecraft that can be turned off
temporarily, military satellites "can't afford to be off
the
air," Tagliaferri said.
The Hubble Space Telescope -- which suffered minor
surface damage in the 1993 shower -- will move to
protect itself against Leonid damage by turning away
from the stream of particles, an option being
considered by many satellite owners.
First reported by Chinese astronomers back in 902,
the Leonid meteoroid storms -- so-named because
they are found in front of the constellation Leo --
become intense every 33 years. They occur when
Earth passes through a trail of dust left behind by the
comet Tempel-Tuttle.
Scientists aren't sure when the heaviest showers will
occur - Nov. 17, 1998, or Nov. 18, 1999.
The spectacular showers will be visible this year
across the Western Pacific and Eastern Asia; the
1999 showers will be visible in the Middle East,
Eastern Europe and Central Asia. Storms last 90
minutes to two hours.
Back in 1966, when fewer than 100 satellites circled
the Earth, the comet produced peak showers of
144,000 meteors each hour and no major damage.
This year, with more than five times the number of
circling spacecraft, some experts think the rate could
be 5,000 to 100,000 an hour.
But astronomer Donald Yeomans of NASA's Jet
Propulsion Laboratory in Pasadena put the rate as low
as 500 to 2,000 particles per hour. And Brown agreed
that the rate won't be as high as it was in 1966.
--
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