Dielectric properties of Apollo 11 lunar samples and their comparison with Earth materials

Presented here are values of dielectric permittivity, dissipation factor, and electrical conductivity of Apollo 11 lunar samples 10020, 10057, and 10046 in the frequency range 100 Hz to 10 MHz and temperature range from −196°C to + 200°C. The dielectric properties determined on earth basalts and a simulated lunar material with the composition of the Surveyor 5 results are used to characterize the dielectric properties of these lunar samples. We conclude that: (1) the lunar samples have higher values of the dielectric constant than terrestrial basalts, an effect due probably to the presence of ilmenite in the lunar samples, and the high-frequency dielectric constant of the lunar igneous samples is about 9 to 15, whereas that of the lunar breccia is about 6 to 9; (2) the lunar samples show greater dielectric losses than terrestrial basalts, and the loss tangents measured on the lunar igneous samples are consistently higher than those of the lunar breccia, ranging from 0.09 to 0.2 for the igneous samples and 0.5 to 0.09 for the breccia; (3) the electrical conductivity values for the lunar samples are 10−9 to 10−11 (ohm cm)−1, and the electrical conductivity of the lunar igneous samples depends more strongly on temperature than that observed for the lunar brecica; (4) all the lunar samples show a temperature-dependent, low-frequency dispersion that may be due to the combined effect of impurity charges and moisture in the samples that is absorbed from the atmosphere.