Abstract: An autonomous momentum management strategy is proposed to solve the problems of the disturbance to the mission orbit and the influence on long life of the Queqiao-2 relay satellite, which caused by the momentum wheel unloading under the control of thrust. Firstly, a momentum predictive model based on the satellite’s attitude maneuver is established to predict the satellite’s momentum changes, avoiding the problem of momentum wheel saturation during satellite maneuvering. Secondly, an event triggering momentum management strategy is used to achieve autonomous management of the relay satellite on orbit momentum, increasing the jet unloading period effectively. In addition, the coupling jet unloading is adopted to improve the stability of obit maintenance. Finally，the experiments and flight results verify the effectiveness of the proposed momentum management strategy.

Key words: Queqiao-2 relay satellite, predictive model, momentum management, momentum wheel unloading