¹Simon Stapperfend,²Donald B. Dingwell,²Kai-Uwe Hess,³Jennifer Sutherland,⁴Axel Müller,²Dirk Müller,²Michael Eitel,¹Julian Baasch,¹Stefan Linke,¹Enrico Stoll
American Mineralogist 110, 1171-1185 Open Access Link to Article [https://doi.org/10.2138/am-2023-9263]
¹Chair of Space Technology, Technische Universität Berlin, Marchstr. 12-14, 10587 Berlin,
Germany
²Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Theresienstraße 41/III, 80333 München, Germany
³Institut Laue-Langevin, 71 Av. des Martyrs, 38000 Grenoble, France
⁴OHB System AG, Manfred-Fuchs-Str. 1, 82234 Weßling, Germany
Copyright: The Mineralogical Society of America

In the context of evaluating lunar construction options, this study focuses on characterizing the viscosities and glass transition properties of lunar regolith simulants to support the development of additive manufacturing processes using molten regolith. Employing the modular TUBS lunar regolith simulant system, we measured the viscosities of different simulants through high-temperature experiments conducted between 1051 and 1490 °C using concentric cylinder viscometry in air. Additionally, differential scanning calorimetry (DSC) was utilized to evaluate the glass transition temperatures, which were in the range between 689 and 815 °C. The measured viscosity data were parameterized by the Vogel-Fulcher-Tammann (VFT) equation, which is adept at describing the viscosities and related properties of silicate liquids. The measured viscosities were compared with the predicted values of six viscosity models. The model by Sehlke and Whittington (2016) best predicts the viscosities of the tested lunar regolith simulants at superliquidus temperatures, and no model adequately predicts viscosities at the glass transition temperature, indicating a need for further research in this area. We infer that 3D printing technologies based on molten lunar regolith are, viscosity-wise, best constrained to highland regions. The reduced environment on the Moon influences the 3D printing process in a positive manner.