Abstract:

Ensuring that satellites in geostationary Earth orbit (GEO) remain in their allocated station-keeping windows necessitates accurate station-keeping algorithms. Due to the direct relationship between the fuel efficiency of station-keeping trajectories and satellite mass, optimizing propellant consumption can extend satellite lifetime, increase payload capacity, and lower launch costs. In this paper, we propose a nonlinear model predictive control (NMPC) policy for station keeping and collocation of multiple GEO satellites under infrequent high-thrust impulsive control. We develop a sequential convex programming-based approach to find locally fuel-optimal tra- jectories with enforced separation distances between collocated satellites. Numerical simulations with NASA’s General Mission Analysis Tool demonstrate the effectiveness of the proposed NMPC policy for both GEO satellite station keeping and as a collocation strategy for three GEO satellites in a single station- keeping window.