I was a child of World War Two . I saw films of pilots taking off from aircraft carriers and decided that was the only thing I wanted to do. And it had to be flying from sea carriers. Airfields were not enough.

Today, we are on a path of decay. We are seeing the book close on five decades of accomplishment as the leader in human space exploration.

Another hundred years may pass before we understand the true significance of Apollo. Lunar exploration was not the equivalent of an American pyramid, some idle monument to technology, but more of a Rosetta stone, a key to unlocking dreams as yet undreamed.

When you head on out to the Moon, in very short order, and you get a chance to look back at the Earth, that horizon slowly curves around in upon himself, and all of sudden you're looking at something that is very strange, but yet is very, very familiar, because you're beginning to see the Earth evolve.

Some astronauts describe the routine flushing of urine into space, where the freezing temperatures turn the droplets into a cloud of bright, drifting crystals, as being among the most amazing sights they saw on an entire voyage.

Chemical propulsion is obsolete to go anywhere other than the moon.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.

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.