Instead of planning the retirement of the Space Shuttle program, America should be preparing the shuttles for their next step in space: evolving, not shutting them down and laying off thousands of people.

Unless we are able to commit to a permanent growing settlement [on Mars], then I don't think just going there with humans and coming back is worth doing. The expense of planning to come back is like the people who left Europe to come to America and then to turn around and go back to Europe, it really doesn't make any sense at all.

The pilgrims on the Mayflower landed at Plymouth Rock. To my knowledge, they didn't wait around for a return trip to Europe. You settle some place with a purpose. If you don't want to do that, stay home. You avoid an awful lot of risks by not venturing outward.

We can't start over and develop a Saturn 5-type vehicle from scratch.

It's not easy to get human beings into orbit. So far only three nations have been able to do that, with all the resources that they put together. And I'm just a little skeptical that that's going to be done by the private sector without making use of what has been done by the government.

The society of life on Mars, or the challenge of making Mars more livable, will have significant benefits on our attempts to modify and change in some ways the environment here on Earth.

Mars could very well be a staging location for the resources of the asteroid belt. We have to learn how to get a payback somewhere, but it's beyond Mars that the real payoff will come from minerals.