The exploration of the planets is now closer to us in time than the exploration of Africa by Stanley and Livingstone.

It was one thing to have guessed it, another to have had that guess confirmed beyond possibility of refutation.

To be a science fiction writer you must be interested in the future and you must feel that the future will be different and hopefully better than the present. Although I know that most - that many science fiction writings have been anti-utopias. And the reason for that is that it's much easier and more exciting to write about a really nasty future than a - placid, peaceful one.

Almost any seat was comfortable at one-sixth of a gravity.

The one fact about the future of which we can be certain is that it will be utterly fantastic.

We always thought the living Earth was a thing of beauty. It isn’t. Life has had to learn to defend itself against the planet’s random geological savagery.

I'm sure we would not have had men on the Moon if it had not been for Wells and Verne and the people who write about this and made people think about it. I'm rather proud of the fact that I know several astronauts who became astronauts through reading my books.