Neighboring optimal guidance and constrained attitude control for accurate orbit injection

Accurate orbit injection represents a crucial issue in several mission scenarios, e.g., for spacecraft orbiting the Earth or for payload release from the upper stage of an ascent vehicle. This work considers a new guidance and control architecture based on the combined use of (i) the variable-time-domain neighboring optimal guidance technique (VTD-NOG), and (ii) the constrained proportional-derivative (CPD) algorithm for attitude control. More specifcally, VTD-NOG & CPD is applied to two distinct injection maneuvers: (a) Hohmann-like fnite-thrust transfer from a low Earth orbit to a geostationary orbit, and (b) orbit injection of the upper stage of a launch vehicle. Nonnominal fight conditions are modeled by assuming errors on the initial position, velocity, attitude, and attitude rate, as well as actuation deviations. Extensive Monte Carlo campaigns prove efectiveness and accuracy of the guidance and control methodology at hand, in the presence of realistic deviations from nominal fight conditions.