Magnetic cleanliness verification of miniature satellites for high precision pointing

Abstract

The advancement in miniature satellite technology and its increasing usage in scientific and commercial applications presents new and unique challenges, particularly for pointing requirements. These small platforms, often limited in resources, are particularly susceptible to disturbance from residual magnetic dipoles while operating in low earth orbit (LEO). To overcome this issue, the precise identification of a satellite's residual magnetic dipole is crucial to enable the compensation of disturbance torques. However, the use of magnetic materials in modern commercial-off-the-shelf (COTS) technology cannot always be avoided. The pre-launch verification of magnetic cleanliness requirements in a laboratory setting is also a significant challenge for small satellite systems. To address this problem, Fraunhofer Ernst-Mach-Institute (EMI) and Fraunhofer Institute for Physical Measurement Techniques (IPM) have developed a cutting-edge test setup for the precise characterization of small residual dipole moments, with the goal of qualifying the ERNST nanosatellite. This innovative approach aims to provide efficient system verification with minimal time and cost overhead and to establish a dedicated test infrastructure, specifically tailored to tackle the unique challenges and requirements of magnetic cleanliness verification in future miniature space systems. As a promising preliminary result of the first test campaign, the filter wheel mechanism of the ERNST nanosatellite could be optimized, resulting in a significantly reduced magnetic moment of the device, meeting the missions challenging magnetic budget constraints.