Shooting Stars Can Shoot Down Satellites
Kill Your Satellite
Meteoroids have taken out more than a few spacecraft. In addition to Olympus and Landsat 5, other possible victims were the Small Expendable Deployer System (March 1994) and the Miniature Sensor Technology Integration (also March 1994).
Two types of electrical effects are associated with an impacting meteoroid: electrostatic discharges (ESD) and electromagnetic pulses (EMPs). An ESD—you’ll know it as the garden-variety spark—occurs on a satellite when accumulated electric charge is suddenly discharged. It’s the same principle by which you experience a mild electrical shock when you touch something after you’ve been walking across a carpeted floor. The satellite builds up charge simply by traveling in its orbit. Then, when the meteoroid smacks into the charged-up satellite, it acts as a flint to generate the spark.
An ESD is a serious problem for the many integrated circuits on board a satellite. These devices are made from semiconductors like silicon and gallium arsenide, materials that can sustain permanent damage from high voltages. The result of an impact could be a localized ESD, or a more serious problem such as a discharge of the whole satellite, depending on the material of the spacecraft. Some antistatic devices can help prevent static buildup, but no one knows how much buildup they need to prevent because these effects have not been thoroughly studied.
Unlike ESDs, electromagnetic pulses (EMPs) occur when a colliding meteoroid vaporizes on impact and forms a plasma. In a collision, both the meteoroid and a fraction of the satellite evaporate and ionize, instantaneously forming a cloud of plasma. That plasma can then affect equipment such as the RF antenna on board.
The theory that meteoroid-induced EMPs cause catastrophic satellite failures is controversial and, at this writing, unconfirmed. However, researchers have been studying the plasma production associated with hypervelocity impacts for over 30 years. Enough unsolved satellite anomalies have taken place to make the case for EMPs as a damage mechanism. —S.C.