Magnetometer data errors and lunar induction studies

摘要: In this paper we discuss errors in lunar magnetic field data obtained by the Apollo 12, 15, and 16 surface orbiting Explorer 35 Ames Goddard magnetometers implications of these on investigations electromagnetic induction moon. The instruments measure fields up to 300 γ with fluctuations about 15 10 5 fluctuations. Typical measurements are found be order 1 or 1% largest measured. Comparison from 12 has allowed measurement relative gains offsets three between day 323 1969 179 1970. During first half period, (i.e., four lunations magnetometer operation), all generally good agreement differing 2% 0.5 γ, respectively. Commencing fifth lunation two significantly different. degraded operation one both results gain differences increasing 60% offset over eighth lunation. Neither agrees well instrument during later period. x Alsep axis coincides better that but y corresponds magnetometer. It is probable begin malfunction Coincident increase an additional anomaly appears which associated exit spacecraft sun shadow. This error spin plane attains a maximum value 7 decays monotonically within approximately 3 hours shadow exit. probably orientation sensors. Three other also discussed. effects electrical conductivity estimated determining envelope profiles resulting delineated study. Adjustment previously published bulk permeability account for uncertainties, yields µ=1.012±0.011. We conclude careful selection used any study moon its environment best procedure minimizing errors.