12.5 million sq. ft.? Wow...
That translates into enough space for roughly 25,000 inhabitants...
And that's only in the castle. Keep in mind we will have many theaters, libraries, dining halls, and other public spaces. Lots of room outside of it as well.
The castle enclosure is one mile in radius, and it is one of three enclosures we will be lofting into orbit, and then on to Mars, with the three enclosures acting as counterweights to each other as they rotate to produce artificial gravity.
Total capacity would be perhaps a million, but I do not think we could support so many. The green growing things will have enough to do to provide food and oxygen for up to ten thousand of us, and our pets and livestock.
We've been trying to provide for every contingency, and that's why the project has gotten so out of hand.
we are trying to avoid making a space-borne analogue of Calcutta, thankyooverrahmuch.