Study of a drag-free satellite orbit control

Theoretical problems pertaining to the control of a pre-established orbit were considered. The analysis of the orbital motion was performed with regard to the evaluation of the orbital perturbations due to the drag compensation system and errors in the earth potential model. A trajectography study was carried out for the geopotential phase with a view to determining a locally improved model of the earth potential then, during the operational phase, to observing the satellite position departure from ephemerides. Two correction procedures are proposed in a slow and fast mode. From the results it is possible to foresee the feasibility of an economical control system capable of ensuring that the satellite will follow within 25 m ephemerides suitably established for periods of 30 days ahead.