Impact of extreme thermal cycling on the physical and mechanical properties of lunar regolith simulant densified via spark plasma sintering, cold isostatic pressing, and biopolymer bonding using Xanthan Gum

The construction of structurally robust and thermally stable surface infrastructure using in-situ resources is a critical enabler for long-term lunar habitation and future planetary exploration missions. This study investigates three distinct regolith-based fabrication methods: Spark Plasma Sintering (SPS), Cold Isostatic Pressing (CIP) followed by pressureless sintering, and biopolymer-based stabilization using xanthan gum (XG). All specimens were subjected to two thermal cycles representative of extreme lunar temperature conditions (125 °C to –180 °C) to assess degradation pathways. Comprehensive characterization included thermogravimetric analysis, scanning electron microscopy, bulk density measurements, and unconfined compressive strength testing. SPS-fabricated specimens exhibited the highest initial compressive strength and retained superior mechanical and microstructural integrity after thermal cycling. CIP-treated samples demonstrated moderate resilience, maintaining mechanical functionality with limited degradation. XG-amended composites exhibited microstructural degradation and increased porosity associated with deterioration of biopolymer matrix. The results highlight distinct material-dependent responses to extreme thermal conditions and emphasize the importance of material selection based on thermal resilience and degradation behavior. Overall, this study provides insight into the relative performance and limitations of regolith-based materials under extreme thermal conditions, contributing to the development of resource-efficient construction strategies for extraterrestrial environments.