Excavation of Lunar Regolith with Rippers for Improved Energy Efficiency

Abstract

As humanity's activities expand to the Moon, Mars, and other extra-terrestrial bodies, it will be necessary to use local resources rather than bringing everything from the Earth. This concept is called In-Situ Resource Utilization (ISRU), which starts with excavation and earthmoving. The present study focuses on loosening and moving of the lunar regolith by a ripper (or rake) and a wide blade. After characterizing the lunar regolith and two of its simulants (JSC-1A), the relationship between the excavation energy and different conditions, namely, relative density— a ratio describing the density of a material with respect to its maximum and minimum density —, and tine spacing on a rake, is investigated with scaled experiments. Prior ripping decreases total excavation energy by up to 20% if the relative density is > 60%. This study has proven that the characteristics of the lunar regolith, i.e. angular grains and high relative density, led to the effectiveness of ripping.