Fabrication of intricate lunar regolith monoliths via freeze casting

Abstract

Sustainable materials processing with in-situ resource utilization is a key priority in lunar exploration to minimize dependence on Earth-supplied materials. Freeze casting is used for the first time to manufacture lunar regolith monoliths with complex shapes and controlled porosity. Stable aqueous slurries of a highlands simulant with varying solid loading were prepared using a low-volume polymeric additive and then cast into various intricately shaped molds. The freeze-dried regolith specimens were sintered between 1100 °C and 1180 °C and achieved relative densities of 35–85 % with compressive strengths of 6 MPa to 36 MPa. This technique has great potential to utilize the lunar cold and vacuum environment for the freezing and sublimation steps, which may reduce the energy consumption required for shape fabrication. Ceramics fabricated this way are candidates for insulating components, interlocking structures, and instrument parts, which are essential for sustained lunar operations.