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.

Crash programs fail because they are based on theory that, with nine women pregnant, you can get a baby in a month.

If we were to start today on an organized and well-supported space program I believe a practical passenger rocket can be built and tested within ten years.

The best computer is a man, and it’s the only one that can be mass-produced by unskilled labor.

Get me a broom. I'll sweep my own office.

The logistic requirements for a large, elaborate mission to Mars are no greater that those for a minor military operation extending over a limited theatre of war.

Man belongs wherever he wants to go - and he'll do plenty well when he gets there.