Collision Avoidance Maneuver Planning and Optimization Considering Control Uncertainty and Mission Requirements

The rise in space traffic congestion has made collision avoidance maneuvers a crucial mode to ensure real-time safety of active satellites. However, performing a collision avoidance maneuver involves the usage of limited on-orbit fuel, losing mission time, incurring operational costs, etc. Therefore, the workload associated with conjunction analysis, the decision on the need to perform a collision avoidance maneuver, and, where appropriate, its design, has increased significantly. In this line, NorthStar has developed a two-step framework for both the decision-making and the design process of a collision avoidance maneuver. In the first step, a multi-objective problem is solved to identify the quantitative trade-offs among the various objectives. Once the suitable maneuver strategy has been identified, an optimal control problem is posed, the solution of which is compliant with high-fidelity dynamics and mission-specific constraints with the possibility of addressing additional safety considerations on top of respecting the stochastic and deterministic miss distance. These can include incorporating the effects of control uncertainty in the trajectory design alongside ensuring consideration for any unforeseen disruption of the propulsion system. The solution is also designed to incorporate orbit maintenance maneuvers and adhere to allotted GEO slots when necessary. The framework has been tested with case studies using CDMs. This paper presents the validation results of the system with emphasis on incorporating uncertainty on the propulsion system performance.