RF Signatures of Hypervelocity Impacts on Spacecraft

Abstract

We investigate the radio frequency (RF) signature resulting from a hypervelocity impact on a spacecraft. While hypervelocity impactors, consisting of meteoroids, dust and orbital debris, are known to cause mechanical damage to satellites, very little is understood about the electrical effects associated with an impact. We present a theory to describe the behavior of the plasma produced from a hypervelocity impact, which results from ionization of both the particle as well as a small part of the spacecraft. The plasma, which does not penetrate the spacecraft chassis, produces a strong electromagnetic pulse (EMP) at a broad frequency spectrum, which can produce electrical anomalies or even catastrophic damage depending on the amount of electrical shielding. We compare our theory to data taken by the Cassini spacecraft in order to understand the resulting RF signature. Our analyses show that RF emission should be a routine outcome from impacts by particles but may only cause anomalies or failures when the impactor exceeds a velocity of 12 km/s.