Physiologically, humans need shelter from the elements, a breathable atmosphere and nutrients. All of those are engineering problems.<p>What happens to a human body when it&#x27;s spent long time in zero-g? I have no idea.<p>Can humans survive psychologically away from earth? Quite a many of us spend quite a lot of time just watching screens so the tiny boxes of first generation colonists might be livable.<p>If we belive physiological and psychological survival is feasible, then the only matter left considering I think is acquisition of raw materials and bootstrapping a colony-based industry.<p>I have no idea of the chemical composition of say, mars, and does is have all of the elements we need for our precious technology. But I would imagine earth is not the only place in the solar system with abundance of the all of the important ones.<p>This last one is a bit of an unknown to me but otherwise you would need to convince  me pretty hard that colonization is not a feasible concept.