As three laws were good enough for Newton, I have modestly decided to stop there.

Space is what stops everything from happening in the same place.

Judge me by my deeds, though they are few, rather than my words, though they are many.

In this single galaxy of ours there are eighty-seven thousand million suns. [...] In challenging it, you would be like ants attempting to label and classify all the grains of sand in all the deserts of the world. [...] It is a bitter thought, but you must face it. The planets you may one day possess. But the stars are not for man.

I believe any malevolent supercivilisation would have rapidly self-destructed as we may be in the process of doing ourselves. If we do have contact, physical contact with aliens, I think it will be benign.

The inspirational value of the space program is probably of far greater importance to education than any input of dollars... A whole generation is growing up which has been attracted to the hard disciplines of science and engineering by the romance of space.

I don't pretend we have all the answers. But the questions are certainly worth thinking about.