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.

I feel we need to remind the world about the Apollo missions and that we can still do impossible things.

When we set out to land people on the surface of Mars, I think we should as a nation, as a world, commit ourselves to supporting a growing settlement and colonization there. To visit a few times and then withdraw would be an unforgivable waste of resources.

I poured the wine into the chalice our church had given me. In the one-sixth gravity of the moon the wine curled slowly and gracefully up the side of the cup. It was interesting to think that the very first liquid ever poured on the moon, and the first food eaten there, were communion elements.

Long-term, I see robotics prevailing on the moon. . . . The most important decision we'll have to make about space travel is whether to commit to a permanent human presence on Mars. Without it, we'll never be a true space-faring people.

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

The final frontier may be human relationships, one person to another.