NASA is evaluating the potential risks to spacecraft posed by the upcoming Draconid meteor shower in 2011, a seven-hour storm of tiny space rocks that could possibly damage major Earth-orbiting spacecraft like the International Space Station.
Meteor shower risk assessment is more art than science, and some variations have been predicted for the 2011 Draconids by meteor forecasters. Because of this, spacecraft operators are being notified to weigh out defensive steps.
Current forecast models predict a strong Draconid storm, possibly full-blown, on October 8, 2011, according to William Cooke of the Meteoroid Environment Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama.
Cooke confirmed that the Draconids do pose some threats to spacecraft.
Cooke and Danielle Moser of Stanley, Inc., also of Huntsville, presented their Draconid data at Meteoroids 2010 — an international conference on minor bodies in the solar system held May 24-28 in Breckenridge, Colorado.
Predicted intensity rates for the 2011 storm could range from a few dozen to several hundred per hour.
A meteoroid stream model at the Marshall Space Flight Center takes past Draconid showers into account in predicting a maximum hourly rate, and suggests that the 2011 shower could reach several hundred per hour.
Cooke told Space.com that past strong Draconid storms of 1985 and 1998 caused no significant electrical problems to spacecraft, but said that should not be taken lightly with the upcoming 2011 event.
Although, due to the Draconids slow speed, the chance of electrical anomalies is relatively low, Cooke noted.
Also, some spacecrafts are well protected for such issues. The International Space Station, for example, is heavily armored against orbital debris. “We don’t expect anything to go wrong there,” said Cooke.
“I have no concerns about the space station. Even if the Draconids were a full-scale meteor storm I would be confident that the space station program would take the right steps to mitigate the risk,” Cooke said.
He noted that the crewmates on board the ISS, however, should avoid doing any spacewalks during the event.
For Hubble, if the risk seems high enough, operators will most likely point the observatory away from the Draconid radiant — the point from which the shower emanates.
“Any time you take a mitigation strategy, like changing a spacecraft’s attitude or turning off high-voltage, that incurs risk as well,” Cooke said.
Each spacecraft is unique, and components have differing thresholds for damage, so programs are encouraged to conduct analytical studies to determine whether or not mitigation strategies are necessary for next year’s Draconids.
Cooke noted that the threat to spacecraft from meteor showers in the past, such as the Leonids in 1998, produced more hype than it did impacts.
“We really didn’t understand what was going on,” he added. “Now we have a much better feel. But the Leonids did sensitize spacecraft operators to worry about meteor showers. Perhaps, sometimes, they worry more than they should.”
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