Ricerc@Sapienza

Low-thrust propulsion was proven to allow substantial propellant savings with respect to high-thrust systems, at the price of increasing the time of flight. This work addresses low-thrust orbit transfer optimization, which consists in finding the thrust direction time history that minimizes the time of flight. The indirect heuristic method is outlined and employed. It is based on the joint use of a heuristic technique and the necessary conditions associated with the optimization problem.

This work presents a unified guidance and control architecture, termed VTD-NOG & PD-RM, and describes its application to low-thrust orbit transfer from a low Earth orbit to a geostationary orbit. The variable time-domain neighboring optimal guidance (VTD-NOG) is a feedback guidance technique based upon minimizing the second differential of the objective function along the perturbed trajectory, and was proven to avoid the numerical difficulties encountered with alternative neighboring optimal algorithms.