Too many people, when they get old, think that they have to live by the calendar.

I think no matter where we go in space to me the important thing is not only getting there and getting back, but it's also doing research, because that opens up as a possibility with that new distance of travel in space.

Exploration, of course, is going to new places, but I don't think we go to new places just solely to say: "Well, we've been there," and come back, interesting though it may be. To me, each time we go farther into space we should use that to do basic research - basic research that can't be done before you go there.

The moment of twilight is simply beautiful.

The most important thing we can do is inspire young minds and to advance the kind of science, math and technology education that will help youngsters take us to the next phase of space travel.

If there is one thing I’ve learned in my years on this planet, it’s that the happiest and most fulfilled people I’ve known are those who devoted themselves to something bigger and more profound than merely their own self interest.

This is a day we have managed to avoid for a quarter of a century. We've talked about it before and speculated about it, and it finally has occurred. We hoped we could push this day back forever.