Intelligent Small Satellite Swarm Control System for Avoiding in Space Debris

This paper describes an intelligent software system for controlling satellites in a swarm to avoid space debris. This software system, called Coordinated Autonomous Debris Avoidance (CADANCE), was developed with funding and direction from NASA. CADANCE uses trajectory optimization and case-based reasoning (CBR) to create a sequence of thrust controls for every satellite in the swarm, based on incoming Conjunction Data Messages (CDMs) and mission objectives. CADANCE uses a trajectory optimization algorithm called Particle Swarm Optimization (PSO) to plan the sequence of maneuvers required to execute the high-level plan. This approach can plan maneuvers to avoid space debris for satellites in diverse swarm and formation types, including but not limited to massive internet provider swarms, science missions, Earth observation swarms, and trailing formations. The main significance of this work is to prove, in simulation, the feasibility of autonomously controlling satellites in a swarm to avoid conjunctions, so we tested CADANCE in eight unique simulated scenarios with CDM data from real satellites. The scenarios were diverse, with different swarm types, mission constraints, and conjunction risks. We used a different satellite simulation software for PSO then we used for testing to avoid bias. CADANCE could find a conjunction avoidance maneuver for every scenario that reduced the Probability of Collision <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathrm{P}_{\mathrm{c}})$</tex> to below a given threshold while obeying all mission constraints. Additionally, CADANCE's trajectory optimizer was always capable of planning a series of maneuvers to match the trajectory requested by the High-Level Planner to within 5 meters. CADANCE is computationally efficient, which will enable it to run on radiation- tolerant computers in space.