System-Trajectory Optimization of Hybrid Transfers to the Geostationary Orbit

This paper proposes a methodology for deriving system-trajectory optimization to Geostationary orbit. The features of chemical and electric propulsion are exploited to deliver the payload onto the final orbit. Hybrid transfers may fill the gap between classical high-thrust transfer, which are fast but mass penalizing, and long-duration, all-electric new solution with lighter platforms. Low-thrust increases the transfer time, thus the radiation absorption through the Van Allen Belts has to be estimated; moreover, elements of system design are combined with those of trajectory optimization. These involve power subsystem design with solar array degradation analysis, electric and chemical propulsion modeling, and multi-spiral, low-thrust trajectory optimization. The system-trajectory design becomes payload-centric to provide the widest range of options, in order to deliver the most tailored solutions to customers. Hybrid transfers may be conceived as a viable option to reach the Geostationary orbit providing attractive total trip times and, at the same time, feasible launch masses.