Near-Term NASA Mars and Lunar In Situ Propellant Production: Complexity versus Simplicity

Abstract

Martian in situ propellant production (ISPP) has a fundamental advantage over lunar ISPP because it has much greater leverage. The value of Martian ISPP per liftoff far exceeds that for the lunar ISPP. This study analyzes the challenges and complexity of lunar ISPP versus Mars ISPP and finds that lunar ISPP is so challenging it might not even be feasible, and if it is feasible, the payoff appears to be limited, while the investment is likely to be great. By contrast, Mars ISPP based on atmosphere only is relatively simple with high payoff. NASA is heavily focused on lunar ISPP and seemingly has diminished interest in solid oxide electrolysis of Martian CO 2 to O 2 after an extremely successful demonstration on Mars by MOXIE. This might make sense at first glance, but when the 2 leading candidates for lunar ISPP are analyzed in detail, it is found that they are extremely difficult and challenging to implement, the effort and investment involved in developing and implementing them are high, and the potential payoff is limited. By contrast, Mars ISPP by solid oxide electrolysis cell (SOEC) of CO 2 is comparatively simple and reliable and has high payoff. A SOEC system is basically landed, and a switch is turned on. The only feedstock is the ubiquitous atmosphere. Lunar ISPP involves a seemingly endless number of complex dynamic steps including autonomous traverses of excavator/haulers to unearth (unmoon?) regolith and deliver it to and from a reactor.