>There's still some atmosphere quite high away from Earth, the transition from "not space" to "space" is asymptotic. Not saying otherwise; however, 400km above

>There's still some atmosphere quite high away from Earth, the transition from "not space" to "space" is asymptotic. Not saying otherwise; however, 400km above surface and eg. Stationary orbit are quite different things. >It doesn't matter because ISS is in orbit. Weightlessness is weightlessness, whether you're free-falling in circles, straight at something, or so far away from anything it's hard to calculate who's pulling on you the most. Actually, we don't know that. From a perception perspective, you are right;From a biological perspective, we actually don't know if there is any biological process that may be affected by the free-falling effect, specifically. >"We already know about the realities of space colonization: it’s not possible." The op's assertion seems to be right - most of what we know to date seems to confirm it. Maybe "not possible" is a strong statement, but certainly not feasible, and that is not going to change anytime soon.