Regolith-polymer composites for structurally functional components in extraterrestrial environments

Developing in-situ functional materials for Mars is essential for sustainable habitat construction and load-bearing applications. However, most regolith-based fabrication methods rely on hydration or high-temperature processing, which are incompatible with the low-pressure, anhydrous Martian environment. Here, a regolith-polymer composite is developed using Martian regolith consolidated with a minimal fraction of high-density polyethylene (HDPE) as a recyclable binder. A low-energy process combining moderate pressure (100-350 MPa) and temperature (~220 °C) enables densification without water or oxygen, while enhancing HDPE crystallinity and interfacial bonding between particles and layers. The resulting composites exhibit high mechanical performance, achieving a compressive strength of 61 MPa and a modulus of 2.56 GPa at 10 wt% HDPE, comparable to conventional construction materials. Increasing the HDPE content from 10 wt% to 30 wt% induces a transition from a stiff, strength-dominated response to a more ductile, deformation-tolerant behavior. Thermal cycling over 30 simulated Martian day-night periods shows negligible degradation in mechanical properties. These results demonstrate a sustainable, resource-efficient material system for extraterrestrial manufacturing, enabling mechanically tunable structural components from locally available regolith and recycled polymer resources.