Global trajectory optimization, pathfinding, and scheduling for a multi-flyby, multi-spacecraft mission

The UT Austin team presents their methodology and result for GTOC11, constructing a hypothetical Dyson ring using asteroids encountered by 10 motherships departing from Earth. A pathfinding algorithm for the mothership is designed using a fast lookup table and a robust Lambert solver. Sequencing of unique mothership itineraries is performed by approximating the mass delivered to the ring via a linear data-based estimator trained on simulated asteroid-to-ring trajectories. A detailed derivation for the necessary boundary conditions of the constant-thrust-acceleration indirect optimization problem is presented, with key insights about the magnitudes of the co-states. An indirect boundary value solver finds feasible asteroid-to-ring trajectories for each of the 12 phasing locations in a high-performance parallel computing environment. A genetic algorithm informs the sequencing for the ring station arrival order that gives the highest performance index value. UT Austin’s final submitted solution placed 4th in the competition, with a performance index value of 5885.5, 235 asteroids collected, and a minimum build-station mass of 1.1328×1015 kg.