Refuge Sphere Lunar Village — Life Support Systems and Advanced Construction: In-Situ Resource Utilization, Thermal Energy Storage, 3D-Printed Regolith Structures, and Elimination of Large-Structure Launch Constraints

Technical abstract presenting the life support systems architecture and advanced construction solutions for the Refuge Sphere Lunar Village (DOI: 10.5281/zenodo.19920193). Energy architecture: Stirling engines on surface/subsurface thermal gradient (~4–6 kW continuous); liquid sodium thermal storage in underground regolith reservoirs heated by solar concentrators, discharged through Stirling engines during the 14-day lunar night (~10–13 kW); hydrogen fuel cell backup from ISRU-derived hydrogen. Vanadium dioxide photochromic coating and piezoelectric self-cleaning on solar collection surfaces. Closed-loop life support: hydroponic food production, Sansevieria trifasciata for nocturnal oxygen production (CAM metabolism), Epipremnum aureum for VOC removal, Spirulina algae bioreactors on transparent wall panels, composting, water recovery from air condensation on geothermal heat exchanger, LED circadian lighting, virtual window display panels. ISRU chain: hydrogen reduction of ilmenite (FeTiO₃ + H₂ → Fe + TiO₂ + H₂O at 800–1000°C) + water electrolysis for oxygen and hydrogen recovery. Iron oxide from ISRU used as feedstock for additive manufacturing of curved interlocking regolith blocks — enabling in-situ construction of large spherical structures and eliminating the need to launch pre-assembled large-diameter modules. Regolith-printed blocks also provide additional radiation shielding for inter-module corridors. Full technical design document in preparation.