| Summary: | This thesis presents the design of solar-sail transfer trajectories to a constellation of two spacecraft in displaced vertical Lyapunov orbits at the L2 point of the Earth-Moon system. The constellation provides continuous coverage of the Aitken basin and the lunar South Pole. Initial guesses for the transfers are generated using reverse time propagations of the dynamics, where the control is provided by a locally optimal steering law. These initial guesses are subsequently used to initialize a 12th-order Gauss-Lobatto collocation method. The minimum altitude with respect to the Earth and the Moon are constrained, as well as the maximum rotation rate of the solar sail. Sets of feasible trajectories for both spacecraft with identical launch conditions are sought, such that the constellation can be initiated using a single Soyuz launch. Such a Soyuz launch can deliver two 1160-kg spacecraft into the found transfer trajectories. The first spacecraft subsequently requires a transfer time of 53.06 days to enter its constellation orbit, while the transfer of the second spacecraft takes 67.89 days. This research demonstrates that solar-sail transfer trajectories are a feasible option for future missions in the Earth-Moon system. Aerospace Engineering
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