Attitude Trajectory Design and Optimization for Planar Space-based Solar Power Arrays in Molniya Orbits

Escalating concerns about climate change and the limitations of alternative energy sources have renewed interest in space-based solar power. Among numerous concepts proposed for space-based solar power, the modular flat-plane sandwich configuration has emerged as a promising candidate, owing to its structural simplicity that lends itselfwell to recent advancements inwireless power transmission and on-orbit robotic assembly. As a consequence of its simple structure, there are also new challenges with respect to attitude design due to the coupling of sunlight collection and power beaming on opposing sides of the flat plane. This paper develops a versatile attitude trajectory optimization approach that maximizes power-beaming efficiency for modular space-based solar power configurations in Molniya orbits while minimizing the attitude control effort. The developed optimization approach employs a genetic algorithm to study two attitude design strategies. The first attitude design strategy investigates initially spinning configurations about the ecliptic normal and compares the power-beaming efficiency against solutions using near optimal attitude and spin axis parameters for a one-year period determined through optimization. The second attitude design strategy employs multiple runs of a genetic algorithm discretized at different times of the year, each determining an inertially fixed attitude optimized for a one-month period. These attitudes are then used to design attitude maneuvers, each with an axis and rate of actuation designed analytically. The outcomes of this study determined several viable attitude trajectory optimization and design strategies for multiple space-based solar power system configurations, which generate attitude trajectories that maximize power beaming in Molniya orbits while minimizing attitude control effort.