Standing on the Moon looking back at Earth - this lovely place you just came from - you see all the colours, and you know what they represent. Having left the water planet, with all that water brings to Earth in terms of colour and abudance life, the absence of water and atmosphere on the desolate surface of the Moon gives rise to a stark contrast.

Everyone who's been in space would, I'm sure, welcome the opportunity for a return to the exhilarating experiences there. For me, a flight in a shuttle, though most satisfying, would be anticlimactic after my flight to the moon. Plus, if I pursued a flight myself, people would think that was the reason I am trying to generate interest in public spaceflight. And that's not the purpose - I want to generate interest in long-range space exploration.

There's a need for accepting responsibility - for a person's life and making choices that are not just ones for immediate short-term comfort. You need to make an investment, and the investment is in health and education.

Somebody would think I was trying to get favored treatment because my ancestors had the name Moon. And that's a joke.

Anything we can do in the near future that begins to stimulate the interest of people - seeing somebody down the street have an opportunity to go into space - buoys up the whole neighborhood.

I think the public needs to be reminded just how much inspiration and intention was given throughout the world to be bold, to send human beings to the moon in the '60s and the '70s. It's important now to bring together the nations that weren't able to do it then and help them do it. We need to move forward.

Space architectures capable of supporting a permanent human presence on Mars are extraordinarily complex, with many different interdependent systems.