Additive Manufacturing of Regolith Composites Through UV-Assisted Direct-Ink-write in Simulated Space Environments

Direct-ink-write (DIW) of Lunar and Martian regolith simulants is of particular interest to promote in-situ resource utilization (ISRU) in the upcoming Artemis missions. The span of formulation design parameters for DIW of high solid suspensions of regolith is wide and offers a lot of freedom for additive manufacturing in space environments. Regolith simulants, incorporated in a polymeric binder and used in conjunction with UV-curing solidification after extrusion, enable reduced energy demands for construction of parts, but require precise formulation characterization to successfully cure these dense inks. In this work we investigate several regolith simulants, including LHS-1, LMS-1, and MGS-1, in acrylate-based binders. We utilize photo-DSC in conjunction with the ISO 4049 method to assess cure degree and cure depth respectively, while rheological assessments give us insights into the flowability of these inks. The results from these preliminary tests allow us to produce dense and opaque suspensions which can be printed both at ambient and in a simulated space environment at -30°C. The adhesion at the regolith-binder interface is evaluated through tensile testing on as-printed parts and parts subjected to thermal cycling imitating the typical Lunar or Martian weather conditions. These efforts aim to help guide the future of additive manufacturing through formulation design for both processing and end-use on the Moon and Mars.