Attitude and Momentum Management of Inertial Oriented Spacecraft

Spacecraft attitude and momentum management aims to slow down the accumulation of control momentum gyro (CMG) momentum through active attitude adjustments. This paper is a systematical discussion of the momentum management problem in the inertial space. The paper can be mainly divided into two parts, as follows: (1) dynamical/constraints analyses, and (2) optimal controller design. In the analysis part, the stable momentum equilibrium attitudes and the constraints for successful momentum management are presented. The analyses show that inertial oriented spacecraft with momentum management consideration is required to keep one of its principal axes of inertia perpendicular to the orbital plane. Due to the uncertainty of the inertia property, the requirement of absolute perpendicularity is difficult to obtain. To solve this problem, the second part of the paper presents an optimal momentum management controller, in which CMG momentum is feedback controlled to avoid momentum accumulation. Theoretical analyses and simulation results show that the CMG momentum oscillates periodically under the impact of gravitational and aerodynamic torque with no significant growth in magnitude when managed in the inertial space. (C) 2014 American Society of Civil Engineers.