Our sun is one of 100 billion stars in our galaxy. Our galaxy is one
of billions of galaxies populating the universe. It would be the height
of presumption to think that we are the only living things in that
enormous immensity. [1960]
It will free man from the remaining chains, the chains of gravity
which still tie him to this planet. [on the meaning of space travel,
quoted in Time magazine, 10 February 1958]
If we continue at this leisurely pace, we will have to pass Russian
customs when we land on the moon. (Describing his frustration with the
American Space Program during the Cold War).