Reachable Sets for Multiple Asteroid Sample Return Missions

Abstract

In support of future NASA asteroid sample return missions, this thesis examines strategies to reduce the number of feasible asteroid targets. Reachable sets are defined in a reduced classical orbital element space. The boundary of this reduced space is obtained by extremizing a family of convex combinations of orbital elements. The resulting group of optimization problems is solved using a direct collocation pseudospectral technique by a MATLAB application package called DIDO. The reachable sets are examined to narrow the possible valid asteroid choices in order to aid in mission design and analysis of alternative targets. A solar electric propulsion system is modeled with the stay times at each asteroid, Earth departure, and Earth arrival hyperbolic excess velocities implemented as constrained optimization parameters.

The original document contains color images.