DEBRIS-CLOUD COLLISION RISK ANALYSIS - POLAR-PLATFORM CASE-STUDY

The collision risk to the polar platform ENVISAT-1 following an on-orb it fragmentation event is examined. For the breakup examples considere d, it is found that passages of the target (polar platform) through th e debris cloud can produce instantaneous collision probabilities as la rge as five orders of magnitude above the level of the background envi ronment. Probabilistic continuum dynamics is employed to calculate val ues of the debris density at positions of the target along its orbit a fter the breakup event. This method does not explicitly assume a cloud shape (e.g., ellipsoid or toroid) or require an overly simplistic bre akup model (i.e., isotropic). Also included in the method's spatial-de nsity calculation algorithm is an implicit and accurate technique for determining if/when any encounters between the target object and the d ebris cloud actually occur.