轨道退行(orbit regression)会使卫星自旋轴偏离轨道法线。扰动力矩,例如气动力矩,重力梯度力矩,太阳辐射压力力矩和磁力矩,也能引起自旋轴的漂移。印度地球观测实验卫星Bhaskara是近地圆轨道自旋稳定卫星,其自旋轴沿轨道法线定向,采用冷气推进系统来控制其自旋轴的定向和自旋速率。对于该卫星而言,每一自旋周期内重力梯度力矩平均为零。气动力矩是个以轨道频率旋转的矢量,故净漂移很小,在设计阶 Orbit regression causes the satellite spin axis to deviate from the orbital normal. Disturbing moments such as aerodynamic moment, gravity gradient moment, solar radiation pressure moment and magnetic moment can also cause spin axis drift. Indian Earth Observation Experiment Satellite Bhaskara is a near-Earth orbiting orbiting stable satellite whose spin axis is oriented normal to the orbital plane and is controlled by an air-cooled propulsion system to control the orientation and spin rate of its spin axis. For this satellite, the average of gravity gradient moments per spin cycle is zero. Pneumatic torque is a vector of orbital frequency rotation, so the net drift is small, in the design order