"I'm urging NASA to foster the development of what I call 'runway landers.' No, that's not the name of a high stakes gambler from Vegas. It's a type of spacecraft that flies to orbit like the retiring Shuttles but then glides to a landing like an airplane on a runway. Just like the Shuttles do."
"When you go to Mars, you need to have made the decision that you're there permanently. The more people we have there, the more it can become a sustaining environment. Except for very rare exceptions, the people who go to Mars shouldn't be coming back. Once you get on the surface, you're there."