Lunar Dust Distributions from Solar Infrared Absorption Measurements with a Fourier Transform Spectrometer

Introduction: The lunar surface is covered with a thick layer of micron/sub-micron size dust grains formed by meteoritic impact over billions of years. The fine dust grains are levitated and transported on the lunar surface, as indicated by the transient dust clouds observed over the lunar horizon during the Apollo 17 mission [1-5] Theoretical models suggest that the dust grains on the lunar surface are charged by the solar UV radiation as well as the solar wind. Even without any physical activity, the dust grains are levitated by electrostatic fields and transported away from the surface in the near vacuum environment of the Moon [6-8]. Since the abundance of dust on the Moon’s surface with its observed adhesive characteristics has the potential of severe impact on human habitat and operations and the lifetime of a variety of equipment, it is of paramount importance to investigate the dust size and density distributions, and the lunar dust levitation and transportation phenomena in order to develop appropriate mitigating strategies. This critical information is essential for understanding the lunar environment. This white paper addresses the critical need for measurements of the dust vertical density and size distributions in the lunar environment. The proposed technique for evaluation of the vertical density distribution is based on solar infrared absorption measurements with a Fourier transform spectrometer in the middle infrared spectral region (5-25 μm; 4002000 cm) with a spectral resolution of ~ 10 cm.