Hybrid propulsion using electrostatic forces for spacecraft swarms

In high Earth orbits, spacecraft surface charging due to ambient plasma and the photoelectric effect can produce disruptive electrostatic forces to the order of 10-1000 micro-Newtons between close-flying spacecraft flying with separation distances up to 100 meters. Rather than fighting them, these forces could be utilized to propel spacecraft to form a swarm. In this paper, a novel hybrid propulsion system for spacecraft swarms in geostationary or other high Earth orbits is investigated using Coulomb forces and standard electric thrusters. This novel hybrid approach can provide fuel-efficient propulsion over a range of separation distances, reduce spacecraft mass and eliminate differential perturbations found in Geostationary Earth Orbit (GEO). Moreover, the application of artificial potential-field method for path planning combined with sliding mode control, for spacecraft swarm aggregation is demonstrated. The performance of the proposed hybrid propulsion system is illustrated using an example of thirty spacecraft in aggregation.