Carbothermal Reduction System Overview and Developments in Support of the Artemis Program and a Commercial Lunar Economy

Sierra Space has continued to develop the carbothermal reduction system to create oxygen from lunar regolith, optimizing the system to process highlands regolith in support of the Artemis program. Continuous carbothermal processing of GreenSpar250 highlands simulant has been demonstrated in a largely autonomous laboratory system. Production of CO & CO2 has been demonstrated in excess of the target production key performance parameter using direct optical energy at the power level and distribution anticipated in the final lunar application. The system does not require consumables due to the innovative handling methods employed for the melted material. Regolith handling processes were validated to transfer the simulant through a pressure boundary, meter and flow the simulant through the system using various protected mechanisms, and to remove the processed material from the reactor. Optical interfaces were successfully protected from dust and other materials. A new proprietary valve design was tested which showed exceptional resistance to wear from the abrasive regolith simulant material. This valve design was tested for over 10,000 cycles with virtually no change in the overall leak rate, and total leakage of 1 +/- 0.5 SCCM at a pressure differential of one atmosphere. Sierra Space believes this valve design can be easily scaled and utilized for other processes requiring regolith or dust tolerant pressure seals, including crew air locks. Current work is underway to test these aforementioned processes in a thermal vacuum chamber at NASA Johnson Space Center to advance the carbothermal and regolith handling systems to technology readiness level six (TRL 6) for an anticipated Commercial Lunar Payload Services (CLPS) mission.