(221b) Enabling Off-Earth Construction and Isru through 3D Printing of Dense Regolith Suspensions

The Artemis 2024 mission among other NASA-led initiatives, has demonstrated the imminent need for construction of operating bases on the Moon and later on, on Mars. While additive manufacturing (AM) methods are numerous and each provide potential avenues to enable the fabrication of necessary infrastructure, processing difficulties arising from local environments hinder the use of AM methods requiring large thermal or energy-demanding inputs. In contrast, direct ink write (DIW) AM offers a solution for construction in low-temperature, low-gravity, and low-atmospheric environments. However, the formulation factors of DIW suspensions and their effect on extrudability, solidification and shape-retention are typically not well understood when these suspensions are processed in such extreme climates. Utilizing an idealized particle system, we demonstrate a formulation suspended in a UV-curable binder that has the potential to enable AM on other planetary bodies and to optimize in-situ resource utilization. We vary the particle content, bimodal ratios, and binders, to gain insights into the printability of the model suspensions. We assess a curing formulation linked with a printing protocol that enables thorough cure of extruded layers, with solid loadings as high as 70 vol%. We test the compressive strength and particle-binder adhesion properties of parts printed and exposed to harsh thermal cycling emulating the Martian weather. By deconvoluting the characterization of these suspensions, and test-printing them under extreme environments, we show that we can expand the range of construction materials to provide cost-effective solutions for off-Earth construction.