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 research is focused on the definition, analysis, and numerical testing of an effective nonlinear orbit control technique tailored to compensating orbit perturbations, as well as possible errors at orbit injection of low- and medium-altitude Earth-orbit satellites. A general, systematic approach to real-time orbit control is presented, under the assumption that the satellite of interest is equipped with a steerable and throttleable low-thrust propulsion system. Two different operational orbits are considered: (a) very-low-altitude Earth orbit and (b) medium-altitude Earth orbit.