I have learned to use the word 'impossible' with the greatest caution.

It will free man from the remaining chains, the chains of gravity which still tie him to this planet.

What we will have attained when Neil Armstrong steps down upon the moon is a completely new step in the evolution of man.

My experiences with science led me to God. They challenge science to prove the existence of God. But must we really light a candle to see the sun?

Nature does not know extinction; all it knows is transformation. ... Everything science has taught me-and continues to teach me-strengthens my belief in the continuity of our spiritual existence after death. Nothing disappears without a trace.

Development of the space station is as inevitable as the rising of the sun; man has already poked his nose into space and he is not likely to pull it back . . . . There can be no thought of finishing, for aiming at the stars-both literally and figuratively-is the work of generations, and no matter how much progress one makes, there is always the thrill of just beginning.

My friends they were dancing here in the streets of Huntsville when our first satellite orbited the Earth. They were dancing again when the first Americans landed on the Moon. I'd like to ask you, don't hang up your dancing slippers.