Development of a Tool for Planning Fuel-Optimized Collision Avoidance Maneuvers

The need for collision avoidance maneuvers is expected to rise due to growing congestion in low-Earth orbit. This paper presents the development of a tool to automate the generation of collision avoidance maneuvers in response to conjunction events. The tool presented has allowed the Space Flight Laboratory (SFL) to eliminate concerns associated with human error, while concurrently addressing the expected increase in the need for these maneuvers without needing to impose any additional burden on flight dynamics engineers. The automation of this task has reduced the hands-on time required by over 80% when compared to the pre-existing workflow. If the risk associated with an identified conjunction event is too high, a collision avoidance maneuver must be planned to reduce the probability of collision. This tool first assesses the safety of the event assuming no action is taken. The optimal thrust axis, thrust time, and thrust ∆v are selected to design a fuel-optimized collision avoidance maneuver to improve the safety of the conjunction event such that the post-maneuver probability of collision is below a user-configurable threshold. The tool then validates the selected maneuver through simulation to assess the post-maneuver safety of the conjunction event. The final step of the tool is to generate an orbit ephemeris message and a set of time-tag commands. These files are ready for immediate use by operators, requiring no additional processing or intermediary steps. This paper provides justification for the various criteria used to design fuel-optimal collision avoidance maneuvers, including discussion on why alternative approaches are less fuel optimal. The end-to-end operation of the tool has been validated through on-orbit operations, with the tool having been used to design 14 successful maneuvers in support of over 10 active missions. The tool presented therefore provides a robust comprehensive solution for generating fuel-optimal collision avoidance maneuvers. The continued development of automated tools such as the one presented is going to be necessary to address the increasing complexity of space traffic coordination, and the increasing complexity of the space environment as a whole.