Risk prioritization for mitigation planning of orbital debris in Low Earth Orbit

A need exists to develop a metric to assess the risk that orbital debris in Low Earth Orbit (LEO) presents to operational spacecraft; this thesis develops such a metric. The work presented here applies to all debris items in LEO. The approach can rank any set of debris objects against any set of operational satellites in LEO. This approach is unique in that it examines debris as a possible threat against all operational spacecraft given that a suitable Two Line Element (TLE) is available for the item and that the computing resources are available to calculate the probability of collision of the data set. Current debris mitigation techniques examine debris that affect a particular spacecraft, but they do not consider the entire orbital environment and the resulting consequence of a collision. The approach developed in this thesis uses the concept of a Risk Prioritization Number (RPN) as the basis of the debris-ranking methodology. For a discrete set of debris and active spacecraft, an application of the approach identifies the "most dangerous" debris items. Including spacecraft involved in a recorded collision facilitates a basic level of validation for the approach.