Soil Mechanics

Description

The purpose of the soil experiment (S-200) was to obtain data on the physical characteristics and mechanical properties of the lunar soil at the surface and subsurface and their variations in a lateral direction. The experiment provided data on the soil in the vicinity of the landing site for use in the interpretation of lunar history and processes. Specific information was acquired on (1) soil grain size and grain-size distribution from returned samples to enable estimation of in-place density and porosity profiles in the upper few tens of centimeters, (2) compaction, regional and local variability, characterization of different units such as rays, mare, and slopes, and differentiation between deposits of different chemical and mineralogical compositions in terms of density and strength, (3) slope stability, (4) seismic velocity-modulus relationships in the surface material to aid in the interpretation of results from seismic studies, (5) estimates of density, specific heat, and thermal conductivity for analysis of thermal (IR) and heat flow measurements, (6) characteristics of dielectric properties for use in radar backscatter and electrical property studies, (7) gas diffusion through the lunar surface, (8) in-place strength and compressibility of soil, (9) erosion and blowing of dust during LM descent and landing to establish limits of surface contamination by eroded particles, and (10) conditions for terrestrial simulation studies, i.e., sample density, porosity and confining pressure. The information was obtained visually and photographically. Cameras for visual and photograghic documentation, plus the returned samples from other experiments, were used.