Lunar surface dielectric constant, regolith thickness, and 3He abundance distributions retrieved from the microwave brightness temperatures of CE-1 Lunar Microwave Sounder

Abstract

Lunar regolith parameters, such as physical temperature, thickness and dielectric constant, are important in studying regolith features, distribution of lunar resources and evolution of the Moon. There had been no measurement obtained by lunar-orbit-borne microwave radiometer applied to evaluate the properties of lunar regolith before CE-1 Lunar Microwave Sounder (CELMS) being launched. CEMLS is the first passive microwave radiometer in the world to sound the surface of the Moon. The brightness temperatures (T B ) sensed by CELMS include complicated information on the above geophysical parameters. In this paper, algorithms of retrieving dielectric constant, regolith thickness, and 3He content from CELMS brightness temperatures are developed, and the results are compared with those from literature. The results show that the regolith thicknesses are mostly in the range of 4.0–6.0 m, and 43% of them are bigger than 5.0 m. The content of 3He evaluated by retrieved regolith thickness is about 1.03 million tons.