I know: If you're looking down at Earth, you're looking through an atmosphere that has a bit of haze in many places and not just occasional clouds.

There's no doubt that there will be many trials and tribulations along the way in taming space for the benefit of all, unmasking its truths and using the boundless resources available to us. Taking a chance allows us to seek new horizons -- and we all benefit from being horizon hunters.

If you want poets in space, you'll have to wait.

I have no doubt that humans will go to Mars. And I feel that America has led so many things in space - we have invested so much, and we have a lot to gain - that America could and should be the nation that should lead the settlement of Mars.

Russia perhaps is still entertaining the possibility that the moons of Mars might have access to ice or water.

Having walked on the Moon, I know something about what we need to explore, really explore, in space.

Climate has been changing for billions of years.