Lunar Surface and Subsurface Magnetic Susceptibility Instrumentation

Multicoil induction measurements of the lunar surface and subsurface magnetic susceptibility are under study. Major considerations are the improvement of the accuracy and logging ability of various probe configurations. Special boundary conditions of high vacuum, extreme ambient temperature variation, restriction to mechanically passive systems, simple electronics, low power and light weight all contribute to degradation of the accuracy of the instrument. Measurements in the range of 10 to 100,000 micro-oersted/gauss are of interest. Nonsedimentary rocks range from 40 to 1000 ¿-oersted/gauss and the presence of nickel-iron meteoritic material may extend the range beyond the present limits of measurement. The determination of the presence or absence of meteoritic material is necessary to validate not only the accuracy of the susceptibility measurement, but also the accuracy of low level magnetometer measurements.