[1] The lunar surface is characterized by a collisionally evolved regolith resulting from meteoroid bombardment. This lunar soil consists of highly angular particles in a broad, approximately power law size distribution, with impact-generated glasses. The regolith becomes densified and difficult to excavate when subjected to lunar quakes or, eventually, manned and unmanned activity on the surface. Solar radiation and the solar wind produce a plasma sheath near the lunar surface. Lunar grains acquire charge in this environment and can exhibit unusual behavior, including levitation and transport across the surface because of electric fields in the plasma sheath. The fine component of the lunar regolith contributes to the operational and health hazards posed to planned lunar expeditions. In this paper we discuss the mechanical response of the regolith to anticipated exploration activities and review the plasma environment near the lunar surface and the observations, models, and dynamics of charged lunar dust.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2005RG000184

Lunar surface: Dust dynamics and regolith mechanics

31008, 2012. Sternovsky, Z., et al., Dust spectroscopy of the Jovian satellites, 43rd Lunar and Planetary Science Conference, Abstract #2929, 2012. Stevens, M.H., et al., Bright polar mesospheric clouds formed by main engine exhaust from the Space Shuttle’s final launch, J. Geophys. Res., 117, D19206, doi:10.1029/2012JD017638, 2012. Stroud, R.M., et al., Constraining the origin of impact craters on A1 foils from the Stardust Interstellar Dust Collectors, LPI Science Conference Abstracts, 43, 2001-2012. Strub, P., et al., Dynamics of interstellar dust in the solar system: From in-situ measurements to models, European Planetary Science Congress 2012, 60-, 2012.

Laboratory for Atmospheric and Space Physics

Seabed Fluid Flow

Meteorite impact on the lunar surface produces a consistent, broadly graded soil. In this note, the geotechnical and geological systems are compared to characterize lunar soil. In geotechnical terms, the lunar soil particle size distribution is described as sandy silt/silty sand, well-graded. In geologic terms, it is described as very fine sand, very poorly sorted, nearly symmetrical, and mesokurtic. Because of its broad particle size distribution, lunar soil may be internally erodible.

Particle Size Distribution of Lunar Soil

For the success of planned missions to the moon in the near future, it is essential to have a thorough understanding of the geotechnical behavior of lunar soil. However, only a limited amount of information is available about geotechnical properties of lunar soils. In addition, the amount of lunar soils brought back to Earth is small. To help the development of new regolith moving machines and vehicles that will be used in future missions, a new lunar soil similant JSC-1A has been developed. A group of conventional geotechnical laboratory tests was conducted to characterize the geotechnical properties of the simulant, such as particle size distribution, maximum and minimum bulk densities, compaction characteristics, shear strength parameters, and compressibility.

Geotechnical Properties of JSC-1A Lunar Soil Simulant

The index properties of returned lunar soils from the United States Apollo and the Soviet Luna programs are reviewed. The scope of the paper includes lunar soil genesis, particle types, grain size distribution, grain shape distribution, specific gravity, minimum and maximum density, and relative density. The writers also present their own data for the latter three properties, as determined on three 1-gm submillimeter lunar samples taken on Apollo 14 and 15. The lunar soils are shown to be well-graded silty sands to sandy silts, composed of many different particle types (mineral fragments, glasses, agglutinates, basalts, and breccias) all produced primarily by meteorite impacts on the lunar surface. The specific gravity varies from 2.90 to 3.24 and the minimum and maximum bulk densities vary from 0.87 to 0.10 g/cm³ and from 1.51 to 1.89 g/cm³, respectively. The in situ lunar soil can have a low relative density at the surface, increasing rapidly to a very high relative density at depths greater than 10 to 20 cm.

The nature of lunar soil

Seafloor Sediments in Orinoco Delta, Venezuela

Characteristics of lunar soil are examined. The paper includes topics such as lunar soil genesis, particle types, grain size distribution, grain shape distribution, specific gravity, minimum and maximum density, and relative density. Lunar soil, consisting of complex mixtures of mineral fragments, miscellaneous glasses, agglutinates, and lithic fragments, is produced primarily by meteorite impacts. The grain size distributions for soils exposed to meteorite reworking for 100 million yr or more are classified as well-graded silty sands and sandy silts. The specific gravity of submillimeter lunar soil samples varies from 2.9 to 3.24 and individual particles range from 1.0 to greater than 3.32. Differences in specific gravity, intragranular porosity, particle shape, surface texture, and grain arrangements result in wide ranges in minimum and maximum densities. Meteorite impacts cause in situ lunar soil to have a low relative density at the surface which increases rapidly to a very high relative density at depths greater than 10 cm to 20 cm.

Arshud Mahmood

Papers

The nature of lunar soil

The nature of lunar soil

Seafloor Sediments in Orinoco Delta, Venezuela

The nature of lunar soil