Solar-System Escape Trajectories Using Solar Sails

摘要

This study explores the use of simple guidance laws that minimize or maximize orbit energy along a solar-sail trajectory to achieve escape conditions. We have established that maximizing the change in orbit energy at every instant along the trajectory does not necessarily minimize the time to escape. We found in general that first maximally decreasing energy and then maximally increasing energy leads to shorter escape times than escape trajectories that only maximally increase energy. These trajectories not only achieved escape in shorter time spans, but they also achieved escape using smaller values of β as compared with initially circular and elliptic trajectories. Using these controls, it is feasible to launch relatively poor performance solar sails (β = 0.3) into escape trajectories from the sun in less than one year. For high-performance sails (β ≥ 0.4), the time to escape is insensitive to the energy minimizing/ maximizing control strategy. Unlike most other works, we have focused on finding a general strategy for solar escape instead of designing trajectories for specific missions. Future research can begin with these simple controls to find generally applicable optimization strategies and can consider controls that maximize the final escape energy of the sail.