Meteoroid impacts on spacecraft: sporadics, streams, and the 1999 Leonids

This paper considers impact effects such as penetration damage and plasma generation on satellites in Low Earth and Geostationary orbits. We characterise the spacecraft impact damage for the normal sporadic background and the annual meteoroid showers, and, especially consider the quantitative effects which would occur should the 1999 apparition of the Leonids reach 'storm conditions'. In this case, the meteoroid shower has the damage potential which could exceed the sporadic meteoroid background by several orders of magnitude at peak. Impact velocities are considered and formulae for penetration, or, plasma charge production are presented. It is found that the Leonids exceed any other stream in terms of plasma current generation even under normal 'quiescent' conditions. Due to the flux enhancement associated with a storm condition, spacecraft could suffer up to one year's worth of normal impact damage, with a few spacecraft suffering potentially catastrophic plasma discharge events, and with the largest likely impact being able to penetrate of order 1 cm of solid aluminium.