The Pioneer I, Explorer VI and Pioneer V High-Sensitivity Transistorized Search Coil Magnetometer

The magnetometer described in this paper was designed for the purpose of measuring the distant geomagnetic and interplanetary magnetic fields. The sensing element is a coil fixed in the frame of a spinning vehicle. The associated nonlinear amplifier has a dynamic range of approximately three decades and an equivalent noise threshold of 6.0 microgauss. This system has been flown in the Pioneer I, Explorer VI and Pioneer V payloads to detect both absolute magnitude and directional changes in the magnetic field intensity at great distances. The complete unit enclosed in an RF shielded container weighs one pound.