Cost Breakeven Analysis of Lunar In-Situ Propellant Production for Human Missions to the Moon and Mars

NASA is preparing to return humans to the lunar surface as a first step to a human
exploration campaign of Mars. Both a sustained lunar campaign and a campaign of missions
to Mars will require tens to hundreds of tonnes of propellant. Although this propellant could
be delivered from Earth, an alternative approach is to use the potentially vast quantities of
lunar ice to enable in-situ propellant production on the lunar surface. This study evaluates
the cost breakeven for using lunar-derived propellants, as opposed to those delivered from
Earth, in support of an extended human exploration campaign with both a multi-year presence
on the Moon as well as multiple crewed missions to Mars. In so doing, the value of lunar
propellant production is considered in the context of future exploration priorities, addressing
the question: over what range of human missions to the lunar surface and Mars does in-situ
propellant production trade favorably with propellant delivery from Earth on the basis of cost?
The results of this analysis show that the magnitude and duration of the lunar campaign, more
so than the Mars campaign, drive the breakeven and that without long lifetime ISRU systems,
with greater than 5 years of autonomous operation before replacement, the demand in cis-lunar
space for a Mars campaign favors propellant delivery from Earth.