Norman Foster: We’ve done two projects: one with the European Space Agency on lunar habitation, and one with NASA on habitations on Mars. And interestingly, to inhabit Mars, the Moon becomes a staging point, which makes that possible in terms of transport.  I think that whole question of space travel — which arguably in its birth was out of a Cold War — but has been a vision of science fiction, and the science fiction of my youth is the reality now. So you could say that science fiction is reality waiting to happen. And in that sense, space travel is less about the idea that maybe the planet will one day be inhospitable, which it may be. But I think that is so far off. So I don’t think it’s about that. I think it’s about doing it because it’s there. Why would you climb a mountain? Why would you build a tall building? Of course, you can do all kinds of rationalizations and justifications. I can tell you statistically the benefits of building height in terms of density and the number of activities that you can get in a tall building, the way it can engage with the ground.  But in the end, it’s like watching kids play or going back to our own childhood where you pile one brick on top of another. I think it’s about stretching boundaries. It’s about flight — overcoming gravity, which is still a wondrous thing. And although I’ve piloted thousands of hours in helicopters, sailplanes, fast jets, vintage biplanes, I still get a thrill from seeing an aircraft take off and land. And I think that, in a way, the whole space travel, the habitations on faraway places, is like putting up the bivouac on the side of a mountain to demonstrate you can do it initially with oxygen and then without oxygen. So I think it’s the human spirit.