answer:It depends if you’re going for the life-support systems or the real thing I guess. Building some artificial dome and grow enough plants to form oxygen would be something that can be created within one generation. People would rely heavily on earth’s support for food, clothes, spare parts and such. Creating something like the ozone layer to re-create an actual atmosphere on the moon is not possible (yet). This would be ideal, creating a much more acceptable size to colonise, grow and produce things to our needs on planet moon. But what happens when this would be reality… I think it would be scary like “the terminator killing all human lifeforms -scary”. A select group of people all lost on planet moon, killing each other to survive. I think it would end in some mad-max weirdo stuff up there…