Environmentally-induced debris sources

Abstract

Resident spacecraft and rocket bodies are known to spontaneously produce large fragments (>10 cm), usually released at low velocities in small numbers and normally exhibiting large area-to-mass ratios. Potential causes of these anomalous events, which are not related to the more dramatic satellite breakups, include material degradation due to environmental stresses and impact by small natural or man-made particles. An examination of known and previously undocumented anomalous events was undertaken to gain better insight into the frequency of such events and the resultant consequences to the overall orbital debris environment. Some space vehicle types, e.g., US Transit spacecraft and former Soviet Vostok orbital stages, demonstrate a propensity for debris generation, while other satellite designs appear less vulnerable. Some satellites are known to produce numerous debris over a period of many years, and the debris exhibit wide-ranging characteristics. It is concluded that such debris currently account for a small portion of the large orbital debris population, but the number of smaller debris cannot yet be estimated. Better identification and analysis of anomalous events might indicate the degree to which small particle impacts are responsible and whether the frequency of anomalous events in given orbital regimes can be used to monitor changes in the small particle population. Modifications to some satellite designs might mitigate anomalous event debris generation.