Boomless Search Coil Sensing With Magnetorquers in CubeSats: Addressing Magnetic Remanence and Interference

Boomless magnetic field measurements represent an enabling technology for CubeSat constellation missions targeting space physics phenomena. The TorqMag concept integrates magnetorquer actuation and search coil sensing within a single hardware unit, achieving dual functionality in a 1U volume by time-multiplexing torque rods between attitude control and AC magnetic field measurement modes. This paper addresses two critical Technology Readiness Level (TRL) challenges inhibiting operational deployment. First, ferromagnetic core remanence persisting after actuation introduces DC offsets 2-3 orders of magnitude above ambient AC signals, degrading sensor sensitivity. Systematic laboratory experiments characterize in-space degaussing sequences across modulation envelope (sinusoidal, ramp, exponential), peak amplitude (±50\% firing voltage), and cycling parameters (1-20 Hz carrier, 7-60 mHz modulation). Results demonstrate exponential decay modulation achieves order-of-magnitude residual field reduction (to