Laboratory investigation of a fluid-dynamic actuator designed for CubeSats

• Investigation of a fluid-dynamic actuator designed for CubeSats.
• Alternative attitude control system is presented.
• Direct-current conduction pump is used for the acceleration of liquid metal.
• Galinstan serves as working fluid.

In general, the attitude control systems (ACS) for precise spacecraft operations rely on reaction wheel technology for angular momentum exchange. In this paper, an alternative ACS concept using fluid rings for this task is presented. This novel actuator—based on Lorentz body force—uses a direct-current conduction pump to accelerate liquid metal within a circular channel structure. As working fluid for the fluid-dynamic actuator (FDA) serves the eutectic alloy Galinstan. Along with a microcontroller that runs the FDA, a MEMS gyroscope is implemented on the device for closed loop operation. Several models of FDAs for small satellites were tested successfully for various attitude control maneuvers on an air bearing platform. Thus advantageous performance has been achieved in terms of torque and power consumption in comparison to similarly dimensioned reaction wheels. Further considerable advantages are wear-free operations and higher reliability as well as expected passive damping properties. A next generation FDA prototype for nano-satellites is currently in development for in-orbit testing.