Designing, Manufacturing, and Testing a Self-Contained and Autonomous Nanospacecraft Attitude Control System

Abstract

This paper describes the development of a three-axis attitude control system for nanosatellites and CubeSats, based on commercial electronics and capable to work autonomously for attitude stabilization or controlled from Earth to perform real-time orientation maneuvers. The system contains three microreaction wheels and related drivers, three magnetorquers with their control circuits, three magnetometers, and control electronics. The system is completely independent from the host spacecraft, with all systems included in its structure. For autonomous attitude control, an external sensor is required, providing the orientation of a reference source, such as the sun, eventually evaluated based on solar array outputs, Earth, or stars. The communication interface is based on a serial link and can be used to transfer commands, parameters, and housekeeping data. Miniaturization of the system components and of the whole assembly are among the main innovations introduced with respect to traditional attitude control system implementations, creating a complete system suitable even for one-unit (1U) CubeSats. The complete system is as small as a 52-mm side cube, weighing 150 g. The development phases of the system are described, from the definition of the design parameters to the realization of the working prototype, focusing on the system miniaturization, electronics design, and functional tests.