The debris stream from comet Tempel-Tuttle is particularly dense, and the Leonid meteoroids travel at very high velocities, nearly 45 miles per second compared to 12 miles per second for average meteoroids. Nevertheless, NASA and Department of Defense experts do not classify the risk to most satellites as serious. With proper precautions, such as pointing vulnerable systems away from the incoming meteoroids, most damage can be avoided. GSFC technicians plan to tilt ACE by 20 degrees and power down sensitive instruments to avoid electrical discharges if a meteoroid should hit. Goddard controllers will take similar steps to protect 22 other GSFC-managed spacecraft including SOHO and the Hubble Space Telescope.
Short circuits are one of the greatest dangers to satellites.
Meteoroids that hit spacecraft can disintegrate, creating a cloud of electrically charged plasma. Under the right conditions, this plasma cloud can set off a chain reaction causing a massive short circuit. The loss of the European Space Agency's Olympus communications satellite in 1993 was attributed to a strike from a Perseid meteoroid , and the resulting plasma discharge that zapped the spacecraft's delicate electronics. For a 10-hour period around the peak of the storm the telescope will be oriented with its aft bulkhead facing into the direction of the meteoroid stream. Hubble's solar panels will lay flat, or parallel to the meteoroid flow.