>>13016942Not that guy but the point of MOXIE is to demonstrate the engineering feasibility of ISRU as Zubrin has been hawking at space agencies since 1993. Of course nothing practical or efficient, but the point is you can get it to work now, with existing technologies which means you can start sending humans now.
The underlying issue for ISRU is that for any number of reasons, fuel mix, life support, system losses or drawoff for other uses, the stoichiometric results from any reaction is not going to match actual demand for the mission as a whole which makes long-term (and lets face it any expedition to mars is going to be long-term) habitation and maintenance extremely uncertain, the space agencies hate that.
And to answer the other anon, too much. But its what you want according to Musk. As far as I know, the Raptor engines are designed to run fuel-rich, at an oxygen-methane mixture ratio of somewhere between 3.5:1 and 3.8:1 by mass.
