Dynamic Cone Penetrometer (DCP) testing on the moon

During the Apollo missions to the moon, penetrometer testing was performed using a device called the Lunar Surface Penetrometer (LSP), which was designed to measure the mechanical properties of the lunar soil. The LSP was a cylindrical penetrometer that was driven into the lunar soil by striking it with a hammer. The force required to drive the penetrometer into the soil was measured and used to calculate the strength and stiffness of the soil.

The results of the penetrometer tests on the moon indicated that the lunar regolith is a loose and porous material with low strength and a low bearing capacity. The tests showed that the regolith was easily compacted by the astronauts' boots, but that it would quickly return to its original state when the pressure was removed. The results also showed that the strength of the regolith was influenced by the grain size and shape of the individual particles, as well as the packing and interlocking of the particles.

The penetrometer tests conducted during the Apollo missions provided valuable information about the mechanical properties of the lunar soil and helped to inform the design of subsequent lunar missions, including the design of lunar habitats, rovers, and other equipment. The results of the tests also helped to further our understanding of the processes that have shaped the moon's surface and the composition of the lunar regolith.

In addition to the penetrometer tests, a number of other in situ measurements were made on the moon during the Apollo missions. These included soil samplings and measurements of the chemical and mineralogical composition of the regolith, as well as studies of the physical properties of the regolith, such as its grain size distribution, porosity, and bulk density. All of these measurements helped to build a comprehensive understanding of the nature and properties of the lunar regolith and its potential applications.

The closest analogue to moon regolith found on Earth is probably volcanic ash or cinder. Volcanic ash is a loose and porous material that is similar in grain size and composition to the lunar regolith. It is formed by the fragmentation of solid rock and ash during volcanic eruptions and is similar to the lunar regolith in that it is composed of a mixture of fine-grained dust and rock fragments.

Volcanic ash and cinder have a similar mechanical behavior to the lunar regolith, in that they are loose and easily compacted under pressure, but quickly return to their original state when the pressure is removed. The physical and mechanical properties of volcanic ash and cinder are therefore useful in studying and understanding the behavior of the lunar regolith, and in developing models to predict the behavior of similar materials on other planetary bodies.

In conclusion, while there is no exact analogue to moon regolith on Earth, volcanic ash and cinder are considered to be the closest terrestrial equivalents and have been used in a number of studies to better understand the mechanical properties of the lunar regolith.