Before deciding what to do about national space policy, Obama set up an outside review panel of space experts, headed up by my friend Norm Augustine, former head of Lockheed Martin and a former government official.

I expected the unexpected and went [on the Moon] with an open mind. I think the visual scene was described by my words on first landing - "magnificent desolation." Magnificent for the achievement of being there, and desolate for the eons of lifelessness.

There are always door openings. And gradually, it accumulates. The opportunities open up in front of you.

By refocusing our space program on Mars for America's future, we can restore the sense of wonder and adventure in space exploration that we knew in the summer of 1969. We won the moon race; now it's time for us to live and work on Mars, first on its moons and then on its surface.

I'm in favor of changing the destination of humans. There are a lot of manned missions that can be done, but not in the direction of the moon.

We're number one on the runway.

Mars is the symbolic and totally stimulating next objective that could so dominate the next century's exploration efforts. From Mars, the resources of all the asteroids will become readily available.