The final frontier may be human relationships, one person to another.

NASA needs to focus on the things that are really important and that we do not know how to do. The agency is a pioneering force, and that is where its competitive advantage lies.

It's real easy to manufacture what you think the people want to hear. But that's not very honest.

There's a tremendously satisfying freedom associated with weightlessness. It's challenging in the absence of traction or leverage, and it requires thoughtful readjustment. I found the experience of weightlessness to be one of the most fun and enjoyable, challenging and rewarding, experiences of spaceflight. Returning to Earth brings with it a great sense of heaviness, and a need for careful movement. In some ways it's not too different from returning from a rocking ocean ship.

The best way to study Mars is with two hands, eyes and ears of a geologist, first at a moon orbiting Mars... and then on the surface.

The big companies are the private industry. But they're faced with a short-term need to show a profit in short-term.

There's a historical milestone in the fact that our Apollo 11 landing on the moon took place a mere 66 years after the Wright Brothers' first flight.