Low-thrust station-keeping towards exploiting the inclined geosynchronous dynamics

Small satellite constellations in Inclined Geosynchronous Orbits (IGSO) provide an alternative to the increasingly crowded Geostationary Orbit belt. Satellite platforms equipped with full-electric propulsion systems are of great capacity for the advantages of significant propellant saving. This work focuses on the IGSO constellation design and its low-thrust station-keeping strategies. An analytical dynamical model based on a triple-averaged Hamiltonian formulation with respect to the ecliptic plane is first applied for a preliminary selection of the frozen orbits, which can serve as the baseline orbit for the whole constellation. Afterwards, the impact of the inclination on the manifolds in the eccentricity vector space is analyzed and the station-keeping slot for IGSO satellites is defined. Then, the low-thrust arc is designed to make the drifting arc closed, which maximize the long-term behaviors due to the resonances. Moreover, by feeding a three-impulse solution to the initial costate guess, an efficient solver to guarantee the convergence of the indirect optimization is proposed. Finally, the efficiency of the constellation design approach and the low-thrust SK strategy are validated via numerical simulations.