An Overview of Planetary Regolith Simulant Development and Testing for Geomechanics and ISRU Research

Sustained human and robotic exploration of the Moon, Mars, and beyond requires a thorough understanding of planetary regolith, the granular surface material covering rocky bodies. Limited availability of returned extraterrestrial samples makes terrestrially manufactured regolith simulants essential for technology development in mobility, excavation, in situ resource utilization, and infrastructure. Designing and using simulants involves trade-offs between compositional fidelity, physical property fidelity, safety, and material availability. This paper provides an overview of best practices and considerations in simulant development, informed by work at the University of Central Florida’s Center for Lunar and Asteroid Surface Science (CLASS). Key factors in simulant design, including mechanical, thermal, and electromagnetic properties, are discussed alongside standard characterization methods. The influence of environmental conditions and preparation protocols on experimental outcomes is also examined. Many of these lessons are not widely published, so this work aims to provide researchers, engineers, and technologists with guidance for creating high-fidelity, well-characterized simulants and experimental protocols. Recommendations include advancing standardized testing procedures, developing open-access simulant property databases, and building large-scale test facilities to improve reproducibility and relevance. A systems-level, interdisciplinary approach to simulant design and testing is critical for ensuring that terrestrial experiments accurately represent extraterrestrial surface conditions, supporting safe and effective planetary exploration and resource utilization.