AAS 98-165

OPTIMIZATION OF SOLAR-PERTURBED DOUBLE LUNAR SWINGBY ESCAPE TRAJECTORIES

C. R. Cassell - University of California, San Diego

Abstract

Double lunar swingby (DLS) escape trajectories employing a multi-month Solar-Perturbed Loop (SPL) between swingbys can be very beneficial for performance to lower energy objectives, such as near-Earth asteroids. Trajectory constraints negating these benefits can be offset with a propulsive impulse during the SPL. A "primer vector" approach is used to develop conditions for introduction and movement of this impulse in the time-fixed problem. The cost function uses a simplified model of the swingby delta-V facilitating this development and decoupling, to some extent, SPL optimization from the rest of the trajectory. The space of SPL reference trajectories is characterized and optimization of selected trajectories demonstrated.

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