The 2025 paper "Numerical Analysis of Coaxially 3D Printed Lunar Habitats" in Microgravity Science and Technology evaluates a coaxial 3D-printing method for lunar habitat walls that deposits a regolith shell and a phase-change material (PCM) core in one process. The authors report that printing parameters such as layer height and extrusion speed can control the internal shell-core geometry, and that the PCM core becomes thicker with smaller layer height or higher extrusion speed. In simulations, adding PCM stabilizes interior temperature toward ΔTi → 0 K, while regolith-only walls require careful tuning of wall thickness and thermo-optical properties to manage mean temperature and fluctuations.
Technically, this is a major habitat-design advance because it couples structure and thermal regulation in a single wall system. The regolith shell provides load-bearing mass, while the PCM core passively buffers thermal swings, reducing reliance on powered HVAC and lowering failure risk during long lunar night or power-shortfall events. The paper also states that the approach can reduce the quantity of required regolith and binder; that matters because binder must be launched from Earth, so any reduction directly improves construction scalability, logistics resilience, and the probability of building large sealed volumes off-world.
Ark action: treat coaxial regolith-PCM printing as a candidate baseline architecture for lunar wall prototypes and thermal-test campaigns. The Ark team should monitor binder-minimization results, PCM selection and containment behavior under vacuum and temperature cycling, and nozzle geometry constraints that determine achievable shell-core ratios. Priority research should compare coaxial printing against regolith-only walls and multi-strand composite walls, with success metrics including imported binder mass, internal temperature variance, crack tolerance, and print reliability in lunar gravity or relevant analog conditions.