There has been some discussion about the potential for damage to G* and other satellites from the Leonid meteorite storm. When I followed your coverage link, I found Intelsat also has a page discussing their Leonid strategy. It was not too long, so I clipped the whole thing.
(PS: You may notice my name is no longer followed by the stigmatizing red "trial member" indication. Last week's QCOM gains paid for the membership.)
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1 July
The Leonid Meteoroid Storm:
INTELSAT's Risk Mitigation Strategy Background
The Leonid meteoroid stream is one of the most famous streams in history. To date the most severe Leonid meteoroid storm occurred in 1966 where the meteor Zenith Hourly Rate (ZHR) was close to 100,000 per hour. The perigee return of parent comet Tempel-Tuttle to the sun in early 1998, close to Earth's orbit, raises the possibility of strong meteor displays. The Leonid activity started in 1997 and is expected to increase dramatically in 1998 and 1999. The storm activity is expected on 17 November 1998 and 18 November 1999. Based on geometric similarity to 1866 and 1932 meteoroid storms, the ZHR is expected to be between 200 to 10,000 per hour. The storm is expected to last about two hours with several hours of build-up and decline. The meteoroid storm will be in a direction that is nearly a 90ø angle to the sun-line.
Potential Risks
Given the high velocity of the Leonid meteoroids, their impact is an order of magnitude larger when compared with typical background sporadic meteoroids. The impact on orbiting satellites could be both mechanical and electrical:
Mechanical in that the Leonids could cause damage to the satellite structures or components. However, based on available technical information, INTELSAT estimates that the probability of such an event on any satellite is very small (less than 0.02%).
Electrical in that meteoroids disintegrating upon impact with the spacecraft could generate a plasma cloud as a result of ionization.
This could lead to electro-static discharge (ESD) on adjacent surfaces.
INTELSAT Risk Mitigation Strategy
INTELSAT is planning to take prudent precautions to safeguard its satellite fleet from the meteoroid storm without interrupting any operational traffic.
INTELSAT's strategy in mitigating the risks posed by Leonids are fourfold, and will be entirely transparent to customers:
1.Satellite solar arrays will be slewed (angled edge-on in the direction of the oncoming meteoroids) to minimize the net impingement area. Fortunately, as the storm direction will be almost at a right angle to the sun line, this will entail slewing the arrays by only 10ø to 12ø for two to three hours. INTELSAT estimates that this strategy alone will reduce the probability of impingement by significantly decreasing exposed satellite surfaces.
2.All ESD safety precautions will be implemented and critical satellite modes will be turned off or "safed" during this period to eliminate uncommanded events or activations.
3.Satellite controllers and on-call engineers will be on full alert during the height of the storm to address any contingencies. While the INTELSAT satellite control center is always staffed 24 hours per day, INTELSAT will have an increased number of staff on-site, who will be fully briefed on procedures to follow in the unlikely event of an emergency.
4.INTELSAT will continue to maintain the close dialogue which it has been entertaining with other owner/operators of satellite systems and academic institutions, and will remain fully informed of possible protective measures. |
