Satellite Collision and Fragmentation Probabilities Using Radar-Based Size and Mass Estimates

Most conjunctions between Earth-orbiting satellites involve unknown objects, typically debris created by explosions or collisions. This study formulates methods to estimate probabilities of collision and fragmentation for such conjunctions, which depend on the estimated sizes masses objects. Analysis radar cross-section (RCS) measurements provides sizes, found be accurate at 90% confidence level within a factor 0.59 potential underestimations 3.1 overestimations. For that experience measurable atmospheric drag orbital perturbations, combining RCS data with orbit determination ballistic coefficients mass estimates factors 0.47 10.9 level. perigee altitudes above 450 km, solar radiation pressure 0.44 5.6 confidence. The risk assessment formulation accounts these size estimation uncertainties. Specifically, conjunction formulated as statistically expected values account RCS-based Fragmentation probabilities, measure likelihood producing more than threshold number fragments, both