Tesseract: A High Stability, Nanosatellite Scale Magnetometer for Constellation Missions

Abstract:

Accurate high-precision magnetic field measurements are essential to many applications in space science including nanosatellite constellation missions studying the magnetosphere. Instrument stability, orthogonality, and linearity are essential to enable meaningful comparison between disparate satellites in a constellation without extensive cross-calibration efforts. Here we describe the design and characterization of Tesseract, a low noise, high stability fluxgate magnetometer sensor suitable for nanosatellite applications. Tesseract’s design takes advantage of a custom low noise racetrack core geometry in novel configuration of two cores per axis. The cores are secured within a single three-axis symmetric glass-filled polyether ether ketone (PEEK) base to create a compact sensor that mitigates impact of thermal stresses on sensor stability. The sensor’s feedback windings are arranged as a four-square Merritt Coil to create a large homogenous magnetic null inside the sensor where the fluxgate cores are held in a uniform, near-zero field, regardless of the ambient magnetic field, hopefully improving the linearity of the sensor response. A Biot-Savart simulation was used to optimize the homogeneity of field around the racetrack core generated by the feedback Merritt Coils and was verified experimentally to be homogeneous within 0.8 percent in each axis. We expect that the three-axis symmetry of the sensor will improve its stability over a large range of temperatures what might be experienced in planetary science missions. Tesseract will be flight demonstrated on the ACES-II sounding rockets, currently scheduled to launch in December 2021 and again aboard the TRACERS satellite mission as part of the MAGIC technology demonstration which is scheduled to launch in late 2023.