Solar Sailing Adaptive Control Around the Earth-Moon Lagrange Point L4 for Stellar Observations

To expand our knowledge about the influence of the Sun in the cislunar region, as well as our understanding of shocks due to Coronal Mass Ejections and large coronal magnetic reconnection, a solar sailing approach is proposed to separately capture lunar occultations and observe the solar corona from L4 of the Earth-Moon system. Single and multiple shooting techniques are described along with a pseudo arc-length continuation method for preliminary orbit design. Periodic orbits in the vicinity of L4 are obtained in the context of the Earth-Moon circular restricted three-body problem (CR3BP) and the Sun-Earth-Moon bi-circular restricted four-body problem (BCR4BP). Solar sailing is shown to offer a solution to a time-constrained problem by leveraging the neutrally stable dynamics of equilateral Lagrange points and solar radiation pressure. To assess mission feasibility, the spacecraft's trajectory is initially designed using low-thrust propulsion in a nonlinear optimal control problem. We further transition solar sailing periodic orbits to a higher-fidelity ephemeris model to account for actual celestial distances and planes of motion, as opposed to the CR3BP and BCR4BP. In short, we achieve propellantless non-planar quasi-periodic motion around L4 while the spacecraft transits the umbra of the Moon once per lunar synodic month using solar radiation pressure for orbit control. Rather than a single trajectory, we find a family of solutions using solar sailing to observe the solar corona and capture lunar occultations across different sail loading parameters. This research proves the feasibility of a mission concept to observe the solar corona and capture lunar occultations of distant stars. The results of this dissertation highlight convergence to solar sailing quasi-periodic orbits with sail characteristic accelerations of up to 0.175 mm/s2. In parallel, an adaptive control architecture, using integral concurrent learning, is proposed to account for fluctuations in the solar flux and degradation of the sail surface for long-term tracking to the nominal trajectory, enabling repeated observations of the solar corona within the Moon's umbra cone. To achieve this, reflectivity control devices are proposed in the geometric mechanics formalism of the Special Euclidean group SE(3) and its tangent bundle TSE(3).