Comparison of Chemical and Stored-Energy Electric Propulsion for Responsive Spacecraft Maneuvers

Abstract Small, responsive maneuvers (e.g., collision-avoidance maneuvers) would typically be conducted with chemical propulsion due to its high thrust. However, ongoing development of high-power electric propulsion systems may enable electric propulsion to be used for responsive maneuvers, providing a higher specific impulse at the cost of a large onboard power supply. An alternative electric propulsion architecture is a stored-energy electric propulsion system, where electrical energy is stored over time onboard the spacecraft and then discharged through the electric propulsion system for the maneuver. This architecture eliminates the need to size the power generation system for the high-power operation of the electric propulsion system, potentially reducing the power system’s mass and volume. In this paper we derive analytical requirements on the propulsion and energy storage systems such that stored-energy electric propulsion would lead to a lower overall system mass fraction than a chemical system for small, responsive maneuvers. We provide requirements for single and multiple maneuvers as well as constant versus variable thruster efficiency. Our results show that stored-energy electric propulsion may be a competitive propulsion architecture with near-future technology for a spacecraft performing multiple small maneuvers throughout its mission.