The magnetometer was a biaxial, closed-loop, fluxgate magnetometer with the two sensors aligned at right angles to one another. After mounting on a short boom (about .61 m), one sensor was aligned parallel to the spacecraft spin axis and the other perpendicular to this axis. Each sensor had a selectable range (50, 100, 200, or 400 nT), an offset field capability (plus or minus 1200 nT in 40-nT steps), and an inflight calibration capability.