Orbit injection maneuvers via indirect heuristic method and variable-time-domain neighboring optimal guidance

Precise orbit injection represents a crucial issue in several mission scenarios, for spacecraft orbiting the Earth as well as in the context of interplanetary flight, because the dynamical conditions at injection affect the subsequent phases of spaceflight. This research is focused on the combined use of two recently-introduced techniques, i. e. (i) the indirect heuristic method (IHM) and (ii) the variable-time-domain neighboring optimal guidance (VTD-NOG), for the purpose of determining accurate orbit injection maneuvers. These techniques are applied to two distinct maneuvers: (a) ascent path and injection into lunar elliptic orbit, starting from the Moon surface, and (b) orbit insertion performed by the upper stage of a launch vehicle. In both cases, IHM reveals extremely effective and accurate in determining the minimum-time path, which is proven to satisfy the first-order necessary conditions and the second-order sufficient conditions for optimality. Then, VTD-NOG is employed in the presence of nonnominal flight conditions, namely (i) errors on the initial conditions and (ii) propulsive perturbations. Both deviations are simulated stochastically, in the context of extensive Monte Carlo campaigns. The numerical results unequivocally demonstrate that the combined use of IHM and VTD-NOG represents an effective approach to determining precise orbit injection maneuvers. © 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.