New Soviet investigations of lunar soil and its analogs: Fid-Bau Portal

New Soviet investigations of lunar soil and its analogs

Cherkasov, I. I. / Shvarev, V. V.

Conclusions In recent years the expedition of the Soviet Lunokhod 2, in which detailed investigations over a 37-km route were carried out, had greatest significance for lunar soil mechanics. A working hypothesis on the origin and composition of the regolith was formulated by scientists of A. P. Vinogradov's school. In terrestrial laboratories the mechanical properties of the regolith from three different regions of the moon were investigated and its analogs were studied. The decisive role of density for the mechanical properties of the regolith and other mineral powders was established and the effect of gases adsorbed on the surface of grains on their interaction at contacts was studied. It was possible to achieve almost complete removal of adsorbed substances from the surface and to show that as a result of this, cohesion increases markedly. Experiments on simulating the processes of formation of glass spheres in the regolith were conducted and indicated two different causes of their formation. Investigations of compressibility and shear strength made it possible to obtain new formulas for the dependence of the void ratio on compressive stress and shear strength, on the angle of internal friction, and on two types of cohesion. A study of the regolith by Soviet scientists is continuing. Specimens of the regolith delivered by Soviet automatic stations are sent to scientists of a number of foreign countries in keeping with international scientific collaboration.