It was very successful, but it fell on the wrong planet.

I only hope that we shall not wait to adopt the program until after our astronomers have reported a new and unsuspected asteroid moving across their fields of vision with menacing speed. At that point it will be too late!

Conquering the universe one has to solve two problems: gravity and red tape. We could have mastered gravity.

Everybody knows what the moon is, everybody knows what this decade is, and everybody can tell a live astronaut who returned from the moon from one who didn't

The same forces of nature which enable us to fly to the stars, enable us also to destroy our star.

Man is not made for space. But with the help of biologists and medical doctors, he can be prepared and accommodated.

I find it as difficult to understand a scientist who does not acknowledge the presence of a superior rationality behind the existence of the universe as it is to comprehend a theologian who would deny the advances of science.