leonid_satellites_001117 WASHINGTON -- While astronomers predict only a minimal blast of dust debris from comet Tempel-Tuttle for the
Leonid meteor shower this week, some spacecraft controllers are on standby alert.For the past two years, measures have been taken to protect Earth-circling satellites from the Leonids. High-velocity particles can wreak havoc with spacecraft, damaging solar panels, as well as delicate sensors.
Hits of speeding comet debris can also spark electrical effects in a satellite, possibly causing control thrusters to accidentally fire.
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The potential severity of the Leonid shower in 1998 and 1999 spurred a number of precautionary action items for satellite ground controllers.
Selected satellites and components were powered down. "A team" personnel took over consoles during the showers. And a number of spacecraft solar panels were adjusted to minimize exposure to incoming storm debris.
Even the ultra-powerful and super-expensive Hubble Space Telescope was oriented to make sensitive parts less vulnerable.
Stay alert
This year, Earth is under the gun, as regards dust particles, from Thursday, November 16, through Saturday, November 18.
"The upcoming shower should be a lightweight compared to last year," said Bill Ailor, director of The Aerospace Corporation's Center for Orbital and Reentry Debris Studies in El Segundo, California.
"It's likely that satellite operators will do
the kinds of things they've done before. Some operators may decide to do very little …others may want to do more. My advice is to just be alert during this period," Ailor told SPACE.com.Scientific predictions show the strength of this year's Leonid
meteoroid shower to be low, said Nicholas Johnson, chief scientist in NASA's orbital debris program office at the Johnson Space Center in Houston, Texas. "It's certainly not comparable to the last couple of years," he said."We're not going to be taking the same level of precautions that we took the last couple of years in terms of our robotic fleet," Johnson said. "We believe the threat is much, much less than it was," he said.
Short worry list
Mark Hess, a spokesman for the NASA Goddard Space Flight Center, said that some actions with the space agency's science satellites are being considered. "Typically, what we do is orient solar panels so their edges face the direction of the particles. That decreases the surface area that can get struck," Hess said.
However, one satellite is on the worry list, although it's a small concern, Hess said.
The International Solar Terrestrial Physics program's Wind spacecraft, Hess said, rides a unique orbit. It literally cuts across the path that the Leonid storm takes on its way toward Earth.
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Safety measures are being taken with the
Hubble Space Telescope, said Ray Villard, a spokesman for the Space Telescope Science Institute in Baltimore, Maryland. "It's not as big a concern as it was in previous years," he said.
Hubble spacewalkers working on the NICMOS instrument.
Telescope operators will slew the huge observatory for a six-hour period, turning Hubble's open eye on the universe opposite to the direction of the speeding meteoroids, Villard said. Even during the meteor shower, the orbiting observatory can continue its astronomical scanning within a 10-degree window -- equal to about 20 Moon diameters, he said.
One impact of the near-at-hand Leonid bombardment was a slip in the launch of the
EO-1 and SAC-C satellites from California's Vandenberg Air Force Base. Don Miles, spokesman for the U.S. Space Command at Peterson Air Force Base, Colorado, said the Delta rocket launch to place the two satellites into orbit now is set for Sunday, November 19.Miles also said that controllers are ready should any of the armada of military spacecraft orbiting Earth run into difficulties. "We're ready if we have problems. We think we're in good shape," he said.
Storm warnings
What about the high-flying crew aboard the
International Space Station?Officials at the NASA Johnson Space Center said no actions are being taken to maneuver the complex in response to the Leonid shower.
"Basically, that's because the probability of any impacts are so extremely remote, it's not worth the cost of propellant and electricity," said James Hartsfield, a space station spokesman at the NASA center.
"It's not deemed to be worthwhile for the minute amount of gain you would get in decreasing the already remote possibilities," Hartsfield said.
While there is minimal threat from "Leonid 2000," experts are already giving early "storm warnings" for 2001 and 2002.
"Next year and the year after, it's going to be a different story," said The Aerospace Corporation's Ailor.
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