From Roxy to Mini-Roxy: The Next Step Towards an Efficient Method for Oxygen Extraction from Regolith

Future exploration missions to the Moon and beyond will be dependent on the use of lunar regolith to produce metals/alloys and oxygen, provided they can be produced very efficiently such that their mass exceeds the mass of any needed consumables or spares to sustain the process. Among the many methods that have been studied so far, molten salt electrolysis with solid oxide membranes appears to be most promising since it meets all of the viability criteria. A specific implementation of this method to lunar applications called ROXY (Regolith to Oxygen and Metals) has been developed and tested, and the design and operations of related demonstration and production facilities have been investigated. As a next step, a miniaturized version of the ROXY cell has been developed, leading to the Mini-ROXY concept and further improvements in terms of process efficiency, and is a new starting point for upscaling the technology.