Flux Gate Magentometer and Boom for Cubesat Mission Beyond Low Earth Orbit

The Foresail-2 and Foresail-3 satellites form part of the COnstellation of Radiation BElt Survey (CORBES), a mission led by COSPAR to study the dynamics of Earth's radiation belts [Wu et al., 2024]. 
Designed to advance our understanding of space weather, the mission requires highly precise magnetospheric measurements to capture proxies of geomagnetic activity and radiation belt behaviour [Anger et al., 2023]. 
To this end, each satellite in the constellation is outfitted with a state-of-the-art fluxgate magnetometer.

The Fluxgate Magnetometer Aboard the ForeSail cubesaT (MAST) was developed by the Space Research Institute of the Austrian Academy of Sciences (IWF). 
MAST is a miniaturized, CubeSat-optimized adaptation of the technology employed in the FIELDS instrument suite aboard NASA's Magnetospheric Multiscale (MMS) mission [Torbert et al., 2016]. 
Central to this innovation is the Magnetometer Frontend Application-Specific Integrated Circuit (MFA), which has been comprehensively redesigned and miniaturized to meet the strict size, mass, and power constraints of nanosatellite platforms.

To ensure accurate magnetic measurements for this mission, the sensor must be mounted at least 50 centimetres from the spacecraft bus to mitigate magnetic contamination from onboard electronics. 
It communicates with the Instrument Control Unit (ICU)—located within the satellite—via UV-protected twisted pair cables, which help suppress electrical interference. Despite its advanced capabilities, the ICU is remarkably compact, occupying a volume of just 14.6 by 8.4 by 3 cm³.

System-level testing has confirmed robust communication between the magnetometer and the satellite’s command and data handling system using a redundant RS485 interface. 
To further validate the full sensor system, a preliminary boom deployment test was conducted using a 3D-printed prototype of the magnetometer boom. 
This early-stage test confirmed the mechanical design and deployment mechanics under controlled conditions. 
Following the successful prototype trial, a metallic flight-like version of the boom has been manufactured and is currently undergoing rigorous functional and environmental testing. 
These tests aim to verify the boom's deployment reliability, structural integrity, and tolerance to launch and space conditions, ensuring its suitability for both the CORBES mission and potential adaptation in future deep space applications.

While initially designed for near-Earth space weather monitoring, the MAST architecture is scalable and holds significant potential for use in interplanetary and planetary missions. Accurate magnetic field measurements are fundamental not only for radiation belt studies, but also for understanding the solar wind interaction with planetary magnetospheres, crustal magnetic anomalies, and plasma environments throughout the solar system.

Future adaptations of the MAST system could support deep space missions to bodies such as Mars, Jupiter’s moons, or asteroids, where magnetic field characterization contributes to objectives ranging from habitability assessment to planetary formation studies. 
The low mass and power footprint of the MAST system makes it particularly attractive for resource-constrained platforms, such as small satellite constellations, ride-along payloads, or even instrument packages on landers and rovers.

By building on the technical developments from the CORBES initiative and the heritage of the MMS mission the MAST system provides a solution for magnetic field investigations across a wide spectrum of space science missions—from low Earth orbit to the outer solar system.

[Wu et al. 2024] Wu J., Deng L., Praks J. et al. ”CORBES: radiation belt survey with international small satellite constellation”, Advances in Space Research, 2024, https://doi.org/10.1016/j.asr.2024.04.051
[Anger et al. 2023] Anger M., Niemel¨a P., Cheremetiev K. et al. ”Foresail-2: Space Physics Mission in a Challenging Environment”, Space Sci Rev 219, 66, 2023, doi: 10.1007/s11214-023-01012-7
[Torbert et al. 2016] Torbert RB., Russell CT., Magnes W. et al., ”The fields instrument suite on MMS: scientific objectives, measurements, and data products”, Space Sci Rev, 2016, 199:105–135, doi: 10.1007/s11214-014-0109-8