Soil-Tool Interaction Theories as They Apply to Lunar Soil Simulant

Abstract

With the establishment of a lunar base, excavation of the lunar soil will be a necessary and time-critical activity. It is the intent of this paper to establish the importance of certain excavation parameters and how they interrelate. With this approach, an overall efficiency of an excavating system can be determined and used as a basis for comparing several excavating systems. This structured approach requires knowledge of the mechanical properties of the lunar soil in its utilization. So, the mechanical properties of the lunar soil and a terrestrial analog are also presented. The analysis of excavating parameters demonstrates that force is a parameter derived from constants. With this parameter the force required to fail the dense lunar soil is investigated. There exists some soil-tool interaction theories developed for finding the force required to fail soil with a blade, given the appropriate parameters of the blade, the soil, and their interaction. These predictive models are used to predict the force required to fail the lunar soil simulant with a flat blade. An apparatus is developed to fail the prepared lunar soil simulant while measuring the required force. Given this data, the validity of the predictive models for use in comparing alternative excavating techniques in this dense lunar soil is determined.