Low-Thrust Maneuvers for the Efficient Modification of Orbital Elements

In this study, low-thrust strategies aimed at the modification of specific orbital elements are investigated and presented. Closed loop guidance laws, steering the initial value of a given orbital element to a target value, are derived, implemented and tested. The thrust laws have been defined analyzing the Gauss form of the Lagrange Planetary Equations isolating the relevant contributions to change specific orbital elements. In particular, considering the classical two body dynamics with the inclusion of the thrust acceleration, both optimal and near-optimal thrusting strategies have been obtained. In the study these thrust laws are described and special focus is given both to the thrusting time and to the total velocity increment required to perform specific or combined orbital parameter changes. The results, obtained by direct numerical simulations of the presented control laws, are compared with analytical approximation and, as study cases, some low-thrust transfers are also simulated. A direct transfer between the standard geosynchronous transfer orbit and the geosynchronous orbit is implemented together with generic demonstrations of the single strategies.