A lot of my role is advocacy, and as a scientist, you're an advocate, too, because you are coming up with a theory and having to convince your fellow scientists that you're right.

One of the big things about space exploration is that it is as expensive as it is complicated, and you need all the countries of the world to help if you want to accomplish big goals.

With the mission to Mars, the whole world wants to get involved. So we actually have 13 different space agencies from around the world working on the global exploration road map.

My key aim is to get man on the surface of Mars by the mid-2030s.

City farming is not only possible, it is the very definition of the kind of meaningful, sustainable innovation we will need to meet the grand challenges of the 21st century: climate change; population growth; ageing population; urbanization; rising demand for energy, food and water; poverty; and access to healthcare.

At Roden Crater, I was interested in taking the cultural artifice of art out into the natural surround. I wanted the work to be enfolded in nature in such a way that light from the sun, moon and stars empowered the spaces. I wanted to bring culture to the natural surround as if one was designing a garden.

Sustainability makes good business sense, and we're all on the same team at the end of the day. That's the truth about the human condition.

Environmental problems cannot be resolved here the way they are resolved in other countries. I heard that 80 per cent of the environmental problems in the U.S. are solved in court. That can't happen here.