The easiest thing is to drill living quarters first, then just drill out. Hardly any oxygen leakage, no solar radiation, and no breaching.
Also, it’s doable on any moon or planet with a solid surface.
Exactly!
And the excess food, oxygen and hydrogen you produce (which you must make anyway) is your export. And brings down the price of more extra-terrestrial growth.
If we’d done that 40 years ago- instead of opting for socialist stagnation- the world economy would be rich and expanding today.