Propellantless Orbit and Attitude Maintenance Strategy for Asteroid Missions

Orbital and attitude motions around asteroids are strongly perturbed and coupled with each other, necessitating frequent maintenance maneuvers to ensure reliable mission operations. This study introduces a propellantless strategy for maintaining spacecraft motion by leveraging environmental disturbances, such as solar radiation pressure and asteroid gravity. The key idea is to repeatedly implement the following three operations: sun-synchronous coupled orbit-attitude motion, orbit correction via solar sailing, and momentum unloading using environmental torques. We validate this novel operation concept through both analytical and numerical analyses based on the flat-plate solar radiation pressure and ellipsoidal gravity models. The proposed method requires no specific devices except for reaction wheels, making it suitable for any asteroid mission. Such an integrated scheme contributes to reducing propellant consumption and operational workload.