Meteoroid Storm May Mean Chaos for World's Satellites
By Patrick Riley
Daring to dispute Bruce Willis, and the rest of the cast of the upcoming film Armageddon, scientists say the real threat to Earth's
near future is not an asteroid slamming into the planet, but a meteoroid storm forecast for this fall that could damage its satellites.
The estimated 500 active satellites in orbit that provide uplinks for communication and research will be "sandblasted" on November
17 by debris from a nearby comet, according to congressional testimony last month by Dr. William Ailor, director of the Center for
Orbital and Re-Entry Debris Studies.
Tempel-Tuttle, the small comet that passed by earlier this year, is trailed by a swarm of dust and sand boiled off the comet by the
sun.
Although the Earth passes through the comet's debris every year, the planet comes closest to the comet itself every 33 years,
resulting in the most intense bombardment — the two to four hour "Leonid" meteoroid storm, so named because it appears to come
from the direction of the constellation Leo.
However, far fewer satellites were in orbit during the last Leonid storm, which struck during the mid-sixties. "This is the first [such
storm] of the modern space age," noted Martin Beech of the Meteor Storm Hazard program in Canada.
The particles of debris will be tiny — no larger than a tennis ball and as small as .01 millimeters — but they will be traveling at a
speed of 72 kilometers per second, more than 100 times faster than a bullet.
"Nearly every satellite will be hit," Ailor told Fox News. "The most likely source of damage will not be from a rock blasting a hole in a
satellite, but rather from a plasma, or free electric charge on the spacecraft" created by the collision, Ailor said before the
Congressional Subcommittee on Space and Aeronautics.
"The charge could cause damage to computers and other sensitive electronic circuits on board the spacecraft, and ultimately cause
the spacecraft to fail," he added.
This occurred in 1993, Ailor noted, when the Perseid meteoroid shower — less intense than a storm — put the European Space
Agency's Olympus satellite out of commission.
Last month, Americans got a taste of the havoc that satellite failure can wreak when one faulty satellite, the Galaxy IV, caused up
to 90 percent of the 45 million pagers used in the United States to go out of service.
PanAmSat, the operator of the satellite, does not attribute the problem to a meteorite. "We believe it was a failure related to the
components in the spacecraft," said Dan Marcus, spokesman for PanAmSat.
The company, which operates 16 satellites and calls itself "the world's largest commercial provider of satellite services," also "does
not believe the Leonid meteor storm poses a significant risk to PanAmSat satellites," according to a written statement.
The company cites the low density of the particles, the short duration of the storm, and the fact that their craft are "designed with
shielding to tolerate collisions with very small particles."
Scientists tend to agree that the effects of the storm will be minimal, and will not likely affect the average earthling. "If it's the
[satellite] that carries MTV, everyone will notice," Beech joked.
Nonetheless, the potential remains for more serious problems, Ailor said, noting that several recommendations have been made to
satellite operators.
"The 'A-team' of controllers should be on duty during the storm, and operators should check the state of health of their satellites
frequently, looking primarily for electrical anomalies and glitches," Ailor said.
He recommends that "recovery plans" be put in place and that satellites be oriented to shield solar panels and other sensitive
components from the onslaught — something NASA plans to do with the Hubbell telescope.
"Each company has their own contingency plans for satellite failure," said Jeff Cohen, spokesman for the Personal Communications
Industry Association, which includes 120 paging companies.
Referring to the Galaxy IV incident, Cohen said, "One of the key lessons that the industry learned was the importance of diversifying
satellite use."
Meanwhile, scientists are hoping to learn from the Leonid storm itself. An "aircraft campaign" currently being planned by several
groups, including NASA and the Search for Extra-Terrestrial Life Institute, would send a number of scientists above the clouds in
planes in November to track and study the Leonid storm.
In addition, Beech and his colleagues plan to use gathered data to develop a computer model of "how the meteor stream itself
changes with time."
"It may also help us to understand whether additional safeguards against the meteoroid impact threat should be included in future
spacecraft designs," Ailor said.
Peter Jenniskens, principal investigator for the campaign and a research scientist at the SETI Institute, said another goal is "to look
for what sort of materials are deposited in the atmosphere from these meteors" and hopefully glean "information about how life
started." |
