In-situ resource utilisation manufacturing of optically transparent glass from lunar regolith simulant

International space agencies are aiming to establish permanent outposts on the lunar surface. For that purpose, new technologies and equipment are being developed which will enable and augment these mission goals. To increase the duration of a long-term planetary mission and to expand mission capabilities, the ability to manufacture transparent glass in-situ could be an important enabler on the lunar surface. Results presented in this work show that it is feasible to use different lunar regolith simulants to manufacture optically transparent glass by magnetically beneficiating regolith prior to processing. Beneficiated regolith simulant was melted, cast into glass nuggets which were then ground, lapped and polished into glass slides of 1 mm thickness. The glass slides’ surface roughness and geometry were measured, prior to optical analysis, which showed an average transmission of about 80% of light in the wavelength range from 250 to 1250 nm. A comparable reference glass sample performed only about 9% (absolute) better on average. From these results, it seems viable to manufacture transparent glass from actual lunar regolith on the lunar surface as well; however, differences in regolith simulant and actual regolith still need to be fully explored—regolith may be available on the lunar surface in unlimited quantities and therefore open up new strategic possibilities.