Control strategies for orbit maintenance of LEO small satellites with FEEP

The object of this work is the definition and performance evaluation of suitable control strategies for a small LEO satellite in the 200 kg class, equipped with a FEEP (Field Emission Electric Propulsion) orbit control system (OCS). A in-house, high-precision orbit propagation code, D-Orbit, has been used to allow for a fast but accurate simulation of the orbit evolution under the propulsion system control. Two different FEEP units, arranged in a single or dual emitter cluster, were considered. Varying the number and geometrical arrangement of such units, 5 different OCS configurations were suggested. Suitable control strategies for each of these configurations were found, in order to achieve maximum performance. These strategies have then been optimized by means of numerical simulations. Finally, performance was evaluated and discussed for different nominal thrust levels.