Quoth humanity.

I am convinced that of all the people on the two sides of the great curtain, the space pilots are the least likely to hate each other. Like the late Erich von Holst, I believe that the tremendous and otherwise not quite explicable public interest in space flight arises from the subconscious realization that it helps to preserve peace. May it continue to do so!

- Konrad Lorenz, On Aggression, 1963

As soon as somebody demonstrates the art of flying, settlers from our species of man will not be lacking [on the moon and Jupiter]... Given ships or sails adapted to the breezes of heaven, there will be those who will not shrink from even that vast expanse.

Johannes Kepler, letter to Galileo, 1610

In spite of the opinions of certain narrow-minded people, who would shut up the human race upon this globe, as within some magic circle which it must never outstep, we shall one day travel to the moon, the planets, and the stars, with the same facility, rapidity, and certainty as we now make the voyage from Liverpool to New York.

-Jules Verne, From the Earth to the Moon, 1865

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

- Wernher von Braun, "A Plea for a Coordinated Space Program" in The Complete Book of Outer Space, 1953

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.

-Wernher von Braun, Time magazine, 1958

The earth is the cradle of humankind, but one cannot live in the cradle forever.

-Konstantin Tsiolkovsky, 1895

The creative conquest of space will serve as a wonderful substitute for war.

-James S. McDonnell

Men might as well project a voyage to the Moon as attempt to employ steam navigation against the stormy North Atlantic Ocean.
— Dr. Dionysus Lardner, Professor of Natural Philosophy and Astronomy, University College, London, 1838.

Be humble for you are made of earth. Be noble for you are made of stars.
— Serbian proverb