There's no doubt who was a leader in space after the Apollo Program. Nobody came close to us. And our education system, in science, technology, engineering and math, was at the top of the world. It's no longer there. We're descending rather rapidly.

There's a need for accepting responsibility - for a person's life and making choices that are not just ones for immediate short-term comfort. You need to make an investment, and the investment is in health and education.

This has been far more than three men on a mission to the Moon; more still than the efforts of a government and industry team; more, even, than the efforts of one nation. We feel this stands as a symbol of the insatiable curiosity of all mankind to explore the unknown.

I think both the space shuttle program and the International Space Station program have not really lived up to their expectations.

Once you've been first, it cannot be done again. Not by you, not by anyone else.

To send humans back to the moon would not be advancing. It would be more than 50 years after the first moon landing when we got there, and we'd probably be welcomed by the Chinese. But we should return to the moon without astronauts and build, with robots, an international lunar base, so that we know how to build a base on Mars robotically.

Mars is there, waiting to be reached.