A 2026 Nature study models an evolutionary thermal architecture for sustainable lunar bases, extending 3D-printed or sintered regolith structures with cavities containing phase-change materials (PCMs).[1] During the lunar day, the PCM melts and stores heat; during the night, it solidifies and releases that latent heat, while the regolith supplies structural support, insulation, and radiation shielding.[1] Related numerical work identifies a 200–300 mm regolith wall as an effective design range; walls above 200 mm suppress temperature fluctuations, requiring more than 12.1 m³ of regolith—roughly 20 tonnes—while walls above 300 mm require more than 18.7 m³.[3]
For civilisation preservation, this converts habitat thermal control from a continuous power burden into a partly passive, locally manufacturable system. Water is a demonstrated candidate PCM, but importing sufficient high-heat-capacity material from Earth would be prohibitive, making lunar sourcing, encapsulation, leak tolerance, and long-duration phase-cycle stability decisive.[1] Thermal buffering should be treated as a life-support function: it can protect seed banks, microbial libraries, electronics, cryogenic systems, and human crews against radiator faults, heater failures, dust degradation, and extended power loss. The design does not eliminate active control; external coatings, radiators, heat rejection, and emergency heating remain necessary.[1]
The Ark team should establish a technology-demonstration programme combining coaxial regolith–PCM printing, lunar simulant testing, vacuum thermal cycling, micrometeoroid and radiation exposure, and fire- and leak-containment trials. Prioritize a 200–300 mm wall trade study; quantify PCM mass, thermal-cycle lifetime, structural performance, radiation dose reduction, and recovery time after power loss. Integrate passive thermal walls into habitat and archive specifications, while monitoring lunar water availability and alternative locally producible PCMs such as salts or metals. Require full-scale tests covering the approximately 14-Earth-day lunar day/night cycle before committing the architecture to permanent repositories.[1][3]