^1,2Dorian Leger,¹Fardin Ghaffari-Tabrizi,³ Matthew Shaw,⁴Joshua Rasera,⁵David Dickson,^6,7Baptiste Valentin,⁸Anton Morlock,¹Freja Thoresen,¹Aidan Cowley Proceedings of the National Academy od Science of the USA (PNAS) 122, e2306146122 Link to Article [https://doi.org/10.1073/pnas.2306146122] ¹Spaceship, European Astronaut Center, Exploration Preparation, Research and Technology Team (ExPeRT), Directorate of Human and Robotic Exploration, European Space Agency, Cologne 51147, Germany ²Cx Bio, Luxembourg 2521, Luxembourg ³Future Mining Team, Commonwealth Scientific and Industrial Research Organisation, Mineral Resources, Clayton VIC 3168, Australia ⁴Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom ⁵Center for Space Resources, Colorado School of Mines, Golden, CO 80401, Colorado ⁶Spaceship FR, Centre National d’Etudes Spatial, Toulouse 31400, France ⁷Belgian Air and Space Component, Control & Reporting Centre, Belgian Armed Forces, Brussels 1140, Belgium ⁸Karlsruhe Institute of Technology, Karlsruhe 76131, Germany Spacecraft using combustion engines require substantial amounts of oxygen for their propellant. The Moon could be a source of oxygen for rocket propellant, since the material composing the lunar surface can be processed to extract oxygen. However, little is known about overall energy requirements of the processes described in the literature for oxygen extraction from lunar regolith. This knowledge gap constrains the planning of lunar missions, since the scale of energy infrastructure required for oxygen production facilities is not well characterized. This study presents an energy consumption model for oxygen production via hydrogen reduction of the mineral ilmenite (FeTiO₃). We consider an end-to-end production chain starting from dry regolith as the feedstock. The production includes the following process steps: excavation, transportation, beneficiation, hydrogen reduction, water electrolysis, liquefaction, and zero boil-off storage. The model predicts the energy demand per kilogram oxygen produced based on adjustable parameters for each process step. As expected, the model indicates a strong dependence on feedstock composition. For regolith composed of 10 wt% ilmenite, the model predicts that a total of 24.3 (± 5.8) kWh is needed per kg of liquid oxygen produced. This study confirms that the hydrogen reduction and electrolysis steps have the highest energy requirements in the production chain. Sensitivity analysis reveals that the enrichment factor of the beneficiation process is the most critical parameter for optimizing energy utilization. Overall, this study provides a parameterized end-to-end model of energy consumption that can serve as a foundation for various production systems on the Moon.