Just to nitpick the gravity argument: I think a major reason there currently is no spacecraft with artificial gravity is that microgravity is the whole point of

Just to nitpick the gravity argument: I think a major reason there currently is no spacecraft with artificial gravity is that microgravity is the whole point of space currently. You could probably build a spacestation with two sides and a long tether, but you don’t want that because you couldn’t do the interesting research anymore.