Demonstration of the low-temperature carbothermal process for producing oxygen from lunar regolith: Terrestrial test campaign

The solid-gas carbothermal reduction is one of the processes available for extracting oxygen from the lunar regolith, a crucial capability for supporting lunar exploration and establishing a sustainable human presence on the Moon's surface. This article presents the findings of the experimental campaign conducted at the Politecnico di Milano, which confirmed the feasibility of the process. Water is extracted from dry regolith, and the production of carbon oxides is monitored to gather data on the process. The campaign studied the influence of various parameters to enhance water and oxygen production, including reaction temperatures, regolith granularity and mass, solid-to-gas ratio, processing duration, and others. The extracted water is collected in a condensation stage, while the evolution of the gaseous mixture is monitored using gas chromatography, and the exhaust batch of simulant is analysed through SEM and XRD. These analyses provided qualitative and quantitative assessments of the reaction's effectiveness, yielding important information about the impact of changing parameters. The study concludes by proposing a set of process parameters to serve as a baseline for future implementation of the low-temperature carbothermal process on the lunar surface.