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.

Don't tell me that man doesn't belong out there. Man belongs wherever he wants to go - and he'll do plenty well when he gets there.

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.

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.

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

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

In 1492 Columbus knew less about the far Atlantic than we do about the heavens, yet he chose not to sail with a flotilla of less than three ships. . . . So it is with interplanetary exploration: it must be done on the grand scale.