Feasibility Study on LGVF for Spacecraft Formation Flight Mission

Formation flight is a key feature for several new space missions concepts, and it consists of multiple spacecraft working as single rigid structure, improving flexibility and redundancy of the mission. Recent studies have shown the possibility to take advantage of Low Earth Orbit for experimental validation of new formation flight technologies. In this context, low-thrust proximity formations are investigated. The main challenge of the onboard system is to guarantee high level of autonomy, mission success and safety. Low-thrust imposes tight requirements for spacecraft relative motion. A novel approach is investigated, where each spacecraft move on a circular trajectory, defined Circular Relative Orbit, with respect to a reference orbit. Failure analysis is carried out to evaluate safety implication of tracking the proposed trajectory. A prediction model based on the presence of external disturbances is designed to improve safety distance in case of complete failure. Lyapunov Guidance Vector Field method is combined with the Artificial Potential Field, and investigated as guidance algorithm for formation flight in Circular Relative Orbit. Simulation campaign is carried out to evaluate the feasibility of the proposed approach for: formation gathering, collision avoidance, and formation reconfiguration.