Risk Assessment of Space Debris Hazards for Global Positioning Spacecraft

An important concern of USSPACECOM has been developing a policy to reduce orbital debris, including ensuring proper spacecraft end-of-life disposal to minimize the number of spacecraft left on mission orbit beyond their useful lifetimes. This paper provides insight to the pertinent issues related to space debris and spacecraft disposal in addition to a detailed analysis of debris hazards for the Global Positioning System (GPS) family of spacecraft as outlined by M. E. Sorge. Results of the analysis show that inactive GPS satellites pose the most significant hazard to the GPS constellation of all space debris of large size, thus reaffirming recent U.S. space policy mandating deorbiting for all GPS satellites deemed non-mission capable. Additional analysis is recommended to explore collision probabilities for medium sized debris, since this category is also capable of disabling GPS satellites.