Revolutionizing Space Weather Sensing
A NASA-sponsored team at the University of Iowa is reviving and advancing a critical capability in magnetic field measurements that underpin space weather research. By developing high-fidelity fluxgate cores in-house, the UI team is restoring a national capability to probe magnetic disturbances that can disrupt communications, navigation, and power grids on Earth, as well as missions and assets in space.
From Legacy to Modern Fluxgate Technology
Fluxgate magnetometers are widely used in space science, but their performance has long depended on a veteran ferromagnetic core technology originally developed for the U.S. Navy. The civilian space community largely lost access to the legacy manufacturing processes and materials. The UI project tackles this gap by fabricating new cores from first principles: starting with base metal powders, melting them into custom alloys, rolling the material into thin foils, shaping the fluxgate geometry, and heat-taint aging to optimize magnetic properties. The result is a modern fluxgate core that can be integrated into spaceflight-grade magnetometers without relying on the old, hard-to-reproduce methods.
In-House Manufacturing and Design Innovation
By designing, prototyping, and manufacturing the cores, sensors, and paired electronics in-house, the team can explore new sensor geometries tailored to different missions. The process is now well documented, and the majority of produced cores meet noise-floor targets comparable to or better than legacy cores. This in-house capability enables reliable mass production for the SWIM payload and future missions, reducing risk and accelerating development cycles.
Meet SWIM: A Miniaturized, High-Performance Sensor
The Space Weather Iowa Magnetometer (SWIM) represents the latest evolution in UI’s fluxgate design. SWIM builds on a core lineage from MAGIC’s Tesseract sensor, which launched recently on NASA’s TRACERS mission. But SWIM is smaller, lighter, and more power-efficient while maintaining or surpassing the performance of its predecessor. The first flight for SWIM is planned on the University of Oslo’s ICI-5bis sounding rocket, targeting a winter 2025/2026 launch from Andøya Space in Norway.
Three Cores, Three Advantages
In a shift from MAGIC’s six large racetrack cores, SWIM employs three smaller cores of the same geometry. This change yields a roughly 30% reduction in sensor size, with the potential to minimize mass further through mechanical optimization. A lighter sensor eases integration with deployable booms, and, with carbon-composite covers, SWIM could weigh around 110 g—facilitating placement on small satellites with stringent mass budgets.
Power, Heat, and Radiation Tolerance
Reduced core count and advanced metallurgy drive a twofold decrease in SWIM’s power consumption compared with MAGIC. Even modest power savings matter for deployable boom designs, where heat dissipation can influence boom stability and pointing accuracy. Importantly, SWIM’s electronics topology supports operation in high-radiation environments. The team replaced traditional analog demodulation with digital demodulation and implemented temperature-compensated, digital, pulse-width-modulation magnetic feedback. These changes bolster reliability for long-duration missions, including radiation belt explorations or planetary cruise phases.
Electronics Redesign for Future Missions
Beyond the cores themselves, the SWIM instrument features a redesigned electronics channel topology that uses lower-performance components while maintaining or improving measurement fidelity. This approach reduces susceptibility to radiation damage and simplifies parts procurement for future missions, opening the door to a broader array of space weather investigations.
Looking Ahead: Opportunities, Partnerships, and Impact
The SWIM fluxgate design is purpose-built for versatility. Its compact form, lower power, and radiation-tolerant electronics extend the range of environments in which precise magnetic field measurements can be taken—from high-altitude atmospheric studies to deep-space cruise investigations. The UI team anticipates multiple flight opportunities, including collaboration on OCHRE (Observing Cusp High-altitude Reconnection and Electrodynamics) and continuing ICI-5bis testing campaigns.
These advances are not only about a single instrument but about sustaining a national capability for high-fidelity magnetic field measurements. By marrying modern materials science with robust electronics and innovative sensor geometries, the University of Iowa’s fluxgate program demonstrates how in-house fabrication can yield reliable, scalable magnetometers for the next generation of space weather research and satellite missions.
Project Leadership and Sponsorship
Project leads include Dr. David Miles of the University of Iowa, with support from the Heliophysics Strategic Technology Office (HESTO). The work embodies a collaborative model that emphasizes in-house expertise, rapid iteration, and a clear pathway from prototype to flight-ready hardware.
