I think we need to move to the moons of Mars and learn how to control robots that are on the surface. It's not the impatient way of getting there, but Mars has been there a long time.

This has been far more than three men on a mission to the Moon; more still than the efforts of a government and industry team; more, even, than the efforts of one nation. We feel this stands as a symbol of the insatiable curiosity of all mankind to explore the unknown.

Is the destiny of the human species to sit back and play with our mouse and computer and imagine, fantasize?

I'm not in favor of just taking short-term isolated situations and depleting our resources to keep our climate just the way it is today.

The honor you have given us goes not to us as a crew, but to ... all Americans, who believed, who persevered with us. What Apollo has begun we hope will spread out in many directions, not just in space, but underneath the seas, and in the cities to tell us unforgettably what we will and must do. There are footprints on the moon. Those footprints belong to each and every one of you, to all mankind. They are there because of the blood, sweat, and tears of millions of people. Those footprints are the symbol of true human spirit.

The energy varies with the square of the velocity, so if you need five times the velocity, that's 25 times the energy.

I inherited depression from my mother's side of the family.