Curiosity is the essence of human existence. 'Who are we? Where are we? Where do we come from? Where are we going?' I don't know. I don't have any answers to those questions. I don't know what's over there around the corner. But I want to find out.

If you begin to think you're something you're not, you're looking in the wrong mirror.

I hold the world speed record downhill, in a Rover. I think it was 17 kilometers per hour, downhill.

The mass gross absence of sound in space is more than just silence.

I think America has a responsibility to maintain its leadership in technology and its moral leadership in the world, to explore, to seek knowledge.

Yes, I am the last man to have walked on the moon, and that's a very dubious and disappointing honor. It's been far too long.

It's our destiny to explore. It's our destiny to be a space-faring nation.