New guidance and control techniques for lunar ascent and orbit injection

This work deals with two distinct guidance and control architectures for autonomous lunar ascent and orbit injection: (i) Variable-Time-Domain Neighboring Optimal Guidance and Constrained Proportional Derivative attitude control (VTD-NOG&CPD) and (ii) locally-flat near-optimal guidance and nonlinear reduced-attitude control. While (i) represents a well-consolidated implicit-type guidance, briefly outlined in this work, (ii) is a new explicit guidance scheme, accompanied by a novel quaternion-based reduced-attitude control algorithm, which enjoys quasi-global stability properties. Attitude control is aimed at pursuing the desired thrust alignment, identified by the guidance algorithm. Actuation, based on thrust vectoring, is modeled as well. Extensive Monte Carlo simulations prove the effectiveness of the guidance, control, and actuation architecture proposed in this study for precise lunar orbit insertion, in the presence of nonnominal flight conditions.