Review of Lunar Regolith Properties for Design of Low Power Lunar Excavators

Lunar regolith is the product of the intermittent comminution of rocks over extremely long durations, and as such is very different from familiar terrestrial soils. A limited amount of information on lunar regolith was collected by the Apollo space program for a few locations. Additional data is required to design effective excavators to prepare outpost sites and to mine the feedstock for production of the material required for a self-sustaining crewed base on the moon. On-site manufacturing would reduce significantly the mass of material that must be launched from Earth. This paper discusses what is known and what is yet unknown about the characteristics and anticipated behavior of lunar regolith as they pertain to efficient excavation operations on the moon. It also discusses the results of tests performed on lunar simulant in dry and frozen conditions and the effects of moisture content as well as temperature on the strength of the frozen material. The results of indentation tests will be presented along with discussion of the cutting forces required for mechanical excavation of the frozen regolith. Implications of material behavior on the design of the cutterhead of excavation systems will also be reviewed.