Space Station attitude control - An overview of requirements and solutions

Attitude control and various structural aspects of NASA's permanent manned Space Station are discussed in the framework of design flexibility, obsolescence as a deterent to a long operational life, modularity, and autonomy. Among the variable factors of specific importance, consideration is given to internal factors, such as inertial variations (up to 400 percent), center of mass movements (up to 28 m), and shifts in modal characteristics, as well as to external torque shifts associated with aerodynamic moments and gravity gradients. The compatibility among multiple-user requirements is also considered. As the Station is a low-orbit spacecraft, its attitude will be greatly affected by the inhomogeneity of the atmosphere, placing a priority on the attitude control techniques. A combination of passive (spring-mass-damper suspension systems) and active (sensor/disturbance-canceling device) systems are expected to be used.