SPRG Seminars
April 10, 2012:
"Electromagnetic Effects from impacts on spacecraft "
Sigrid Close and Ivan Linscott, Stanford
Meteoroid and space debris impacts on spacecraft are known to cause mechanical damage, but the associated electrical effects on spacecraft systems remain poorly understood. We present a theory to explain both electrostatic discharges (ESDs) and electromagnetic pulses (EMPs) resulting from hypervelocity impacts on spacecraft, as well as recent results from ground-based tests. In particular, we focus on EMP and plasma production that occurs when a particle strikes a spacecraft. This plasma, with a charge separation commensurate with different species mobilities, can produce a strong EMP at broad frequency spectrums, potentially causing catastrophic damage if the impact is relatively near an area with low shielding or an open umbilical. Anomalies such as gyro-stability loss can be caused by an EMP without any detectable momentum transfer due to small (< 1 μg) particle mass. Subsequent plasma oscillations can also emit significant power and may be responsible for many reported satellite anomalies. We show that significant radio frequency (RF) emissions occurred in frequencies ranging from VHF through L-band and were highly associated with fast (> 20 km/s) particles.