Maintenance Strategy for Elliptical Orbit Satellite With Air-Breathing Electric Propulsion

Owing to the strong perturbation caused by atmospheric drag, it is inevitable to consume a significant amount of fuel for the orbital maintenance of ultralow Earth orbit (ULEO) satellites. Air-breathing electric propulsion (ABEP) has emerged at the right time, which makes use of the atmosphere to provide propulsion. Aiming to adopt an elliptical orbit, an ABEP-based satellite can collect the atmosphere near its perigee, which can be applied for propulsion to maintain the orbit shape. However, to guarantee propulsive efficiency, the thrusters should not work during the intake process, i.e., near the perigee. This causes difficulties in orbital control methods because propulsion near the perigee is the most effective for simultaneous increasing the semimajor axis and eccentricity. To overcome this problem, this article proposes the "in-orbit balance" strategy, wherein the orbit maintenance can be achieved in closed orbits. Some of these orbits are used for air intake, while others are applied for propulsion near perigee. Considering the requirements regarding working gas, electric power, maneuverability, and temperature, the constraints are analyzed for systematic parameter design. Using equivalent treatments, feasible satellite layout schemes can be searched for, and a constrained optimization problem is constructed to determine the solutions that satisfy the specific engineering requirements. Furthermore, optimal control for a continuous system is applied to allocate the thrust. The simulations verified the efficiency of the parameter design and confirmed that the ULEO can be controlled using the proposed strategy without resulting in extra fuel consumption.