A scalable control moment gyro design for attitude control of micro-, nano-, and pico-class satellites

Utilization of small satellites for missions such as space science, laser communications, and on-orbit servicing applications, which demand precision pointing and in some cases fast slew rates, introduces novel challenges for the attitude control system (ACS). The inherently low inertias of small satellites result in agile vehicles that are responsive to both commands and disturbances. Additionally, the power available for these classes of small satellites imposes a constraint on the ACS. Motivated by these ACS needs and constraints, a pyramidal four single-gimbal control moment gyro (SGCMG) cluster is a viable option for three-axis attitude control of small satellites. This paper presents an analysis/evaluation (e.g., comparisons of several steering laws, power consumption, and accuracy) of the pyramidal SGCMG. Additionally, the paper discusses a miniaturized version of the pyramidal SGCMG design that is applicable for nano- and picosatellite class vehicles. The paper is concluded with a discussion of a hardware-in-the-loop experimental micro-satellite attitude control testbed developed to validate SGCMG concepts.