Space is not just going up and coming back down again. Space is getting into orbit and being there, living there, establishing a presence, a permanence.

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 was given permission to serve myself Communion, with wine and a wafer, on the surface on the Moon. But I was advised not to say anything about it at the time. Someone had strongly objected to the Apollo 8 crew reading from the Bible. We didn't want to get into any further trouble with the religious critics.

A mind concerned about danger is a clouded mind. It's paralyzing.

In my mind, public space travel will precede efforts toward exploration -- be it returning to the moon, going to Mars, visiting asteroids, or whatever seems appropriate. We've got millions and millions of people who want to go into space, who are willing to pay. When you figure in the payload potential of customers, everything changes.

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

When we get there, if we don't find any life on Mars, from that point on there will be life on Mars because we'll bring it there, whether it's germs and leftover urine bags, whatever it is.