Every time I give a talk, I ask the audience - especially if it's kids - how many want to go to Mars. At least half raise their hands. I don't think there's going to be any shortage of volunteers.

We want to make sure we get living astronauts to the surface of Mars.

We have to ask, 'How can we break a huge challenge like sending humans to Mars into a series of doable, affordable steps? How can we break that problem down into chunks in order to keep making progress?'

So many people I talk to who work in technology, you ask them, 'What got you interested in science?' and those from my generation say, 'The Apollo landings.'

Being able to have a laboratory on Mars, being able to have some sort of sustained human presence on Mars in the future, I think, is critically important for science.

Every time I do a movie, I think it's going to be a huge hit.