Ray Bradbury is one who is contributing to the understanding of the imagination and the curiosity of the human race.

Exploration is wired into our brains. If we can see the horizon, we want to know what's beyond.

The purpose of going to Mars is for humans to first begin to occupy, permanently, another planet in the solar system. The astronauts or pilgrims, whatever you might call them, are going to be very historically unique human beings.

There may be aliens in our Milky Way galaxy, and there are billions of other galaxies. The probability is almost certain that there is life somewhere in space.

At the core of the risk-free society is a self-indulgent failure of nerve.

We should go boldly where man has not gone before. Fly by the comets, visit asteroids, visit the moon of Mars. There's a monolith there. A very unusual structure on this potato shaped object that goes around Mars once in seven hours. When people find out about that they're going to say 'Who put that there? Who put that there?' The universe put it there. If you choose, God put it there.

One of the major problems with long-term deep space human flight is the requirement for radiation shielding.