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.

I came to dedicate my life to opening space to the average person and crafting designs for new spaceships that could take us far from home. But since Apollo ended, such travels were only in our collective memory.

Does it make sense for the U.S. to expend hundreds of billions of dollars to mount a new Apollo-style program to return to the moon? Or have we blazed that trail? Shouldn't we help other nations achieve this goal with their own resources but with our help?

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.

There were about six years when there was not one American who went into space. We shouldn't do that again.

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.

When President Kennedy took office, I was in the midst of my education.