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

I think I need to continue to think and plan and marry all of the different things that we could do that make transportation in space from the earth to the space station, from the earth to the moon to space stations around the moon to visiting an asteroid.

I am excited to think that the development of commercial capabilities to send humans into low Earth orbit will likely result in so many more Earthlings being able to experience the transformative power of space flight.

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.

There are a lot of reasons for not doing something. And if humanity had come up with all the reasons for not doing something we wouldn't have spread across the Earth the way we have. There's a curiosity, and I would submit that that curiosity will put human beings on the surface of Mars.

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.

Exploration is wired into our brains. If we can see the horizon, we want to know what's beyond.