I wrote 'Reaching for the Moon' because I wanted to tell kids that all of us have a moon, a dream, that we can strive for. Even if you don't attain it, you can at least reach for it.

Over the years, I think I've matured in my spiritual evolution and development to understand a bit more than the narrow religious thinking - to move beyond that through a sort of perfection of the grandiose nature of the universe, and how perfect it is it in its sense and how satisfied we should all be in our place in that.

There are always door openings. And gradually, it accumulates. The opportunities open up in front of you.

I was given permission to serve myself Communion, with wine and a wafer, on the surface on the Moon. But I was advised not to say anything about it at the time. Someone had strongly objected to the Apollo 8 crew reading from the Bible. We didn't want to get into any further trouble with the religious critics.

Retain the vision for space exploration. If we turn our backs on the vision again, we're going to have to live in a secondary position in human space flight for the rest of the century.

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.

To appropriately respond to an emergency requires a very clear mind, to cooly analyze what the observations are and how to fix it.