Indirect Optimization of Fuel-Optimal Many-Revolution Low-Thrust Transfers With Eclipses

An efficient indirect method is presented to determine fuel-optimal many-revolution low-thrust transfers in the presence of Earth-shadow eclipses. Specifically, events shadow entrance and exit are modeled as interior-point constraints. Following observation that an ill-conditioned state transition matrix may occur when spacecraft flies over edge shadow, a two-level continuation scheme introduced generate trajectories. The established computational framework integrates analytic derivatives, switching detection, with augmented flowchart, which yields discontinuous bang-bang solutions their gradients. Transfers from geostationary transfer orbit simulated illustrate effectiveness efficiency developed.