Lunar Production System for Extracting Oxygen from Regolith

A study was conducted to determine the mass and power of an in situ propellant production plant producing 10.5 t of liquid oxygen per year from the regolith at the lunar south pole. The carbothennal reduction process was selected for oxygen extraction from the regolith, using direct solar energy from a concentrator for the thermal heating in the carbothermal reactor, and solar arrays for the remaining electrical power needs. The baseline lander design selected for delivery of the production plant is capable of landing a payload mass of 3,600 kg and has significant cargo area available below the propulsion deck close to the ground for the in situ resource utilization (ISRU) hardware. Total mass for the 10.5-t oxygen plant, including all power systems, structure, command and control, communication, thermal management, and 30% margin, was 4,145 kg, exceeding the lander's payload capability. A second design of a smaller plant producing 7 t of oxygen per year resulted in a mass of 3,459 kg, which is within the lander's capability. Mass payback ratio for the 10.5- and 7-t oxygen plants is 0.4 and 0.5 (kg hardware)/(kg oxygen/yr), respectively, and indicates that a net gain of mass on the lunar surface can be realized in three to four months. (C) 2021 Published by American Society of Civil Engineers.