Road Map to L4/L5 with a Solar Sail

This paper explores the capability of solar sails to transfer a probe from the displaced L1 and L2 libration points to the region of practical stability (RPS) around the triangular equilibrium points L4 and L5. If the sailcraft arrives inside the RPS with zero synodical velocity, it will remain there with no need for station keeping maneuvers. Moreover, the location of the RPS is ideal for space weather missions as the Sun can be observed from a dierent angle compared to spacecraft orbiting the L1 point. The solar sail unstable mani-folds of the displaced L1 and L2 points come close to these regions providing opportunities for natural transfer trajectories. By varying the solar sail orientation along the manifold, the dynamics are altered and simple transfer trajectories that reach the RPS with few sail maneuvers are enabled. However, these trajectories are not optimal from a transfer time perspective, but they are used in this paper as an initial guess in a direct optimization method to nd minimum-time transfers between the displaced L1 and L2 points and the RPS at L4 and L5.