Trajectory-battery integrated design and its application to orbital maneuvers with electric pump-fed engines

This paper proposes a trajectory-battery integrated design of the electric pump-fed (EPF) engine and demonstrates its application feasibility to orbital maneuvers in low-Earth orbit (LEO). Based on the mass model that comprises the main components of the engine, the advantages of the electric pump system in terms of the structural mass, addition of total impulse and change in velocity that the engine can provide are demonstrated compared with those of the traditional pressure-gas system. The performances of four typical battery cells are assessed to select the suitable cell for the application cases. Besides, the applications of the trajectory-battery integrated design to the specific orbital maneuvers are investigated. Impulsive and continuous control strategies are considered based on the EPF engine limited by the light/umbra condition and charge time. The optimal transfer trajectories considering the charging processes of the battery involved in orbital maneuvers are demonstrated. For the impulsive thrust, the limitation of the battery performance with regard to the effectiveness of the Hohmann transfer is given. For the continuous thrust, the orbital control problem has been turned into an optimization problem and the optimal fuel consumption is obtained using the combinatorial numerical optimization. The simulations confirm the superiority of the EPF engine based on its significant reduction of the structural mass and validate the application feasibility to orbital maneuvers in LEO.