Trips to Mars, the Moon, even orbit, will require that we provide astrotourists with as many comforts from home as possible, including paying each other.

We need to begin thinking about building permanence on the Red Planet, not just have voyagers do some experiments, plant a flag and claim success. Having them go there, repeat this, in my view, is dim-witted. Why not stay there?

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.

I don't believe any pair of people had been more removed physically from the rest of the world than we were.

I believe that space travel will one day become as common as airline travel is today. I'm convinced, however, that the true future of space travel does not lie with government agencies -- NASA is still obsessed with the idea that the primary purpose of the space program is science -- but real progress will come from private companies competing to provide the ultimate adventure ride, and NASA will receive the trickle-down benefits.

Mars has a bit of air pressure; maybe we can build up that atmosphere to be a bit more accommodating to humans.

As we begin to have landings on the moon, we can alternate those with vertical launch of similar crew modules on similar launch vehicles for vertical-launch tourism in space, if you want to call it that adventure travel.