Now I admit I never tried using furnaces on the Moon or so, but in GC's code, I haven't seen anything which would prevent them from working. So I would suggest adding an item swapping mechanics similar to the torches for the vanilla furnace, which then doesn't work without oxygen.
As a bonus, it could work differently in a methane atmosphere, where regular fuel doesn't work, instead other stuff does. Not sure what, though. Oxygen canisters come to mind, not sure what other blocks/items could be assumed to contain enough oxygen to react with methane...
As a bonus, it could work differently in a methane atmosphere, where regular fuel doesn't work, instead other stuff does. Not sure what, though. Oxygen canisters come to mind, not sure what other blocks/items could be assumed to contain enough oxygen to react with methane...