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

To send humans back to the moon would not be advancing. It would be more than 50 years after the first moon landing when we got there, and we'd probably be welcomed by the Chinese. But we should return to the moon without astronauts and build, with robots, an international lunar base, so that we know how to build a base on Mars robotically.

I was not the commander, I was a junior person, so once both were outside, I followed my leader, because we (NASA) had not put together detailed jobs of people outside. I believe it could have been improved. But it was very successful for what it was.

Fear and worry are emotions that cloud the mind from being able to think clearly, to remember what the procedures are to deal with that emergency.

When I was a little kid, we only knew about our nine planets. Since then, we've downgraded Pluto but have discovered that other solar systems and stars are common. So life is probably quite prevalent.

My first inclination is to be a bit skeptical about the claims that human-produced carbon dioxide is the direct contributor to global warming.

I have no intention of selling any more of the historical Apollo 11 items in my possession for the remainder of my life. I intend to pass a portion of these items on to my children and to loan the most important items for permanent display in suitable museums around the country.