Biopolymers can be used for consolidation of lunar and Martian regoliths

Abstract

Creating long-term extraterrestrial habitats to support continuous human occupation requires structures that can bear load, while remaining resilient to large temperature fluctuations. Exploiting locally available regolith is part of a paradigm termed in situ resource utilization (ISRU) that advocates minimal dependence on terrestrial supplies via local resource exploitation for construction. In this work, we report on a consolidation method for making load-bearing structures out of lunar and Martian regolith simulants using biopolymer binders. We quantify the compressive and tensile strength of the final brick-like structures, termed biopolymer regolith composites, and investigate their dependence on biopolymer concentration and chemistry. A pressure-assisted die casting process is developed that can produce bricks with compressive strengths of [~] 15 MPa and tensile strengths of around 2 MPa, from regolith simulants. We finally report on the performance of these bricks under large temperature and pressure variations and find that their strengths remain unchanged. We believe that this makes biopolymer regolith composite bricks suitable candidates for use in harsh extraterrestrial environments, while adhering to the guidelines of the ISRU paradigm. Keyword: Lunar regolith; Martian regolith; Space habitation; Extraterrestrial construction; Biopolymers; Regolith simulant