Implications of Lunar Simulant Geotechnical Properties on Testbed Experimentation and Engineering Analysis and Reported Properties of Colorado School of Mines Highland Simulant

Understanding the mechanical behavior of lunar regolith simulants is essential for advancing engineering analysis for surface infrastructure design and testbed experimentation. This study presents a comprehensive geotechnical characterization of the Colorado School of Mines Lunar Highlands Type Testbed simulants, including a newly developed highland-type lunar simulant contained in the new Mines Lunar Surface Simulator testbed. This investigation includes the determination of fundamental geotechnical properties like particle size distribution, density, compressibility, cohesion, friction angle, and particle morphology, utilizing standardized ASTM testing procedures. Key findings demonstrate that while particle size distribution similarities exist among the simulants and actual lunar regolith, significant differences in density-dependent mechanical behaviors such as shear strength, compressibility, and deformation responses are observed. These results highlight the complexity of simulant fidelity and how this affects testbed experiments when attempting mid-Technology Readiness Level environments. Also, we highlight the importance of density-specific testing when assessing both geotechnical properties and simulant performance. This work represents the first comprehensive publication of the full geotechnical profile of Colorado School of Mines highland simulants and emphasizes the necessity of multi-parameter evaluation beyond particle size distribution alone for assessing simulant fidelity. Future work will focus on characterizing testbed variability and conducting property assessments across a range of density states to further refine lunar simulant applicability in engineering analysis and testbed experimentation.