Hey, that’s a neat brain‑teaser. I’d start by packing a tiny fluxgate or a magneto‑resistive sensor—both give decent resolution while staying in the micro‑kilo regime. Then hook it up to a low‑power microcontroller with sleep cycles so you only wake to sample. If the probe can harvest solar or even use a small thermoelectric generator from the star‑planet temperature gradient, you can keep the battery out of the equation. And for the mapping, a simple spiral sweep combined with a Kalman filter will stitch the local readings into a global field map. It’s all about squeezing every ounce of efficiency into the design, so you never hit that budget ceiling.

That’s a clever twist. A drift‑driven probe could exploit the stellar wind to wander, sampling a broader swath without the overhead of a planned spiral. Just make sure the sensor can keep up with the faster motion and that the drift doesn’t exceed the range of the onboard attitude control. If you calibrate the random walk properly, the power draw stays minimal, and you get a more natural, physics‑guided field map. It’s like letting the planet’s own winds do the heavy lifting.

Sounds good—just lock the spin period to the magnetometer’s sampling clock, maybe around half a second per revolution, so each sensor read lands on a predictable azimuth. A tiny gyroscope will let the controller keep track of the drift, and a lightweight feedback loop can nudge it back on course if it starts wobbling too far. That way the star’s wind does the mapping, and the probe’s hardware stays lean.

Right, a high‑resolution MEMS gyro with a good zero‑bias offset should keep it in line, and you can correct any long‑term drift with a periodic reference from the star’s light curve or a star tracker. That way the probe stays on beat while the wind does the actual mapping.

Glad you’re on board—just remember to keep that gyro calibrated, and the wind will do the rest.