It's been one of the greatest challenges that ever came along in my life; it was one of the more difficult things to do.

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.

There should be an international lunar base. That is certainly doable.

Russia perhaps is still entertaining the possibility that the moons of Mars might have access to ice or water.

Long-term, I see robotics prevailing on the moon. . . . The most important decision we'll have to make about space travel is whether to commit to a permanent human presence on Mars. Without it, we'll never be a true space-faring people.

The future is about wings and wheels and new forms of space transportation, along with our deep-space ambition to set foot on another world in our solar system: Mars. I firmly believe we will establish permanence on that planet. And in reaching for that goal, we can cultivate commercial development of the moon, the asteroid belt, the Red Planet itself and beyond.

Knowledge of the past and an optimistic view of the present give you great opportunities.