Fragments Distribution Prediction for ENVISAT Catastrophic Fragmentation

ENVISAT is currently one of the largest debris in Low Earth Orbit and it resides in a highly populated orbital zone with higher impact risk. A collision with other satellites or rocket stages could generate and scatter fragments into altitudes occupied by many operational spacecraft, and in the worst case could restrict the access to polar orbits at about 800 km altitude. In this context, there is a need to evaluate the contamination of the orbital regions possibly involved by the spread of debris originated after a possible ENVISAT fragmentation. In this paper the results of a campaign of hypervelocity impacts simulations with ENVISAT as target body are presented. A set of potential configurations for the collision have been simulated, varying the impacting body (small-class 100 kg satellite, defunct rocket stage) as well as the impact position (glancing impact on ENVISAT radiator, collision on the central body); for each impact configuration, fragments distributions are reported and the severity of different collision scenarios is discussed. Then, newly generated fragments are propagated to identify and assess local variations of the space debris spatial density. This is achieved by overlaying ENVISAT fragments population to ESA Meteoroid and Space Debris Terrestrial Environment Reference (MASTER) population and studying their evolution with a continuum model.