Kevin Cannon of the Cannon Group at the Colorado School of Mines can help find the answer. In a recent post on his Planetary Intelligence blog, the Assistant Professor of Geology and Geological Engineering describes a trade study comparing extraction of oxygen from regolith such as Metalysis’ ESA funded study to getting O2 from ice mining at the lunar poles as favored by NASA. Nothing stands out from a cursory look at the pros and cons of each approach.
In a more data driven analysis to compare apples to apples, Cannon examines energy costs of mining oxygen and plots it against the amount of bulk material that has to be processed to produce an equal amount of O2 from different sources ranging from plain silicate regolith to various grades of water ice endmembers. The analysis even includes processing material from various types of asteroid resources. The types of ice/regolith mixtures can vary widely as described in one of Cannon’s tweets.
Cannon’s analysis reaches the conclusion that “At 1.5-2% water by weight, icy regolith is essentially on par with O2-from-regolith on a joule for joule basis. In other words, if you had a pile of icy regolith already sitting on the surface, it makes sense to throw it out if the grade is less than about 1.5% and extract oxygen directly from the silicate regolith instead.”
More brilliance from the mind of Kevin Cannon can be found in these posts: Want to eat like a Martian in an environmentally friendly manner?, The logistics of dining off Earth, SpaceX will need suppliers for Mars settlement, The accessibility of lunar ice. And of course, don’t forget to visit kevincannon.rocks.
