“One good test is worth a thousand expert opinions.”

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

Looking back, nothing seems so simple than a utopian vision realised.

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.

I believe in an immortal soul. Science has proved that nothing disintegrates into nothingness. Life and soul, therefore, cannot disintegrate into nothingness, and so are immortal.

The greatest gain from space travel consists in the extension of our knowledge. In a hundred years this newly won knowledge will pay huge and unexpected dividends.

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.

I’m convinced that before the year 2000 is over, the first child will have been born on the moon.

I believe that the time has arrived for medical investigation of the problems of manned rocket flight, for it will not be the engineering problems but rather the limits of the human frame that will make the final decision as to whether manned space flight will eventually become a reality.

With our present knowledge, we can respond to the challenge of stellar space flight solely with intellectual concepts and purely hypothetical analysis. Hardware solutions are still entirely beyond our reach and far, far away.

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.

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!

By the year 2000 we will undoubtedly have a sizable operation on the Moon, we will have achieved a manned Mars landing and it’s entirely possible we will have flown with men to the outer planets.

If we continue at this leisurly pace, we will have to pass Russian customs when we land on the moon.

Basic research is what I am doing when I don’t know what I am doing.

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

The rocket worked perfectly, except for landing on the wrong planet.

For it is the duty of an astronomer to compose the history of the celestial motions through careful and expert study.

I’m convinced that democracy cannot be exported from one country to another, like you cannot expert revolutions, ideology.

History is a matter of debate, it should be left in the hands of historians and experts.

My basic notion regarding the matter of historical recognition is basically, it’s a matter that should be left to the good hands of historians and experts.

Arguments from authority carry little weight, authorities have made mistakes in the past. They will do so again in the future. Perhaps a better way to say it is that in science there are no authorities; at most, there are experts.

So many people are on television that don’t know me, and they’re like experts on me.

It’s easy to be an expert if you’re the only one in the world with an interest.

Thus the expert in battle moves the enemy, and is not moved by him.