Chemical propulsion is obsolete to go anywhere other than the moon. Three days - that's acceptable. But for Mars, we need propulsion technologies to get us there in, say, 60 days - then spend whatever length of time we want to spend and return when we want to come home.

I've been asked about UFOs and I've said publicly I thought they were somebody else, some other civilization.

Here I am at the turn of the millennium and I'm still the last man to have walked on the moon, somewhat disappointing. It says more about what we have not done than about what we have done.

Am I willing to go to Mars? Yes, but I'm not willing to spend nine months getting there, then wait 18 more months until the planets align to come home.

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.

We went into darkness after being in daylight the whole time on the way to the Moon. And then we went into darkness. And we're in the shadow... of the Moon.

One of the most important things about the geology on the moon is your descriptions of what you see, comparing them to things that you've seen on Earth so that the geologists and the scientists on the ground would know what you're talking about; and then take pictures of them.