Balancing Strength and Extreme Thermal Resilience in Lunar Regolith Composites: The Role of Multi-Walled Carbon Nanotubes.

The National Aeronautics and Space Administration's (NASA) Artemis program stands at the forefront of commercial space initiatives, aiming to establish sustainable lunar habitats, demanding resilient construction materials with minimal reliance on Earth-based resources. In response to these demands, this study explores the feasibility of reinforcing lunar regolith with multi-walled carbon nanotubes (MWCNTs) while relying on minimal water and additives for composite fabrication as a potential solution for building semi-permanent Moon bases. Composites incorporating 0.00, 0.25, 0.50, and 1.00 wt.% MWCNTs are subjected to freeze-thaw cycles, vacuum pressures, ambient environments, and oven-curing methods to emulate the Moon's harsh environment. Results show that ambient-cured composites containing MWCNTs achieve compressive strengths exceeding 35 MPa, resulting in a 44.44% increase compared to the sample without MWCNTs, highlighting the reinforcing potential of carbon nanotubes (CNTs) for extraterrestrial applications. However, thermal cycling reveals performance limitations due to mismatched coefficients of thermal expansion between MWCNTs and the regolith matrix, causing microcracking. In contrast, vacuum-cured MWCNT-free samples surpass 45 MPa, indicating that curing protocols can significantly influence densification and mechanical properties. These findings underscore the trade-offs between material composition, curing approaches, and thermal stability, offering key insights into designing robust, resource-efficient lunar construction.