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.

My own American Dream was to serve my country as best I could and make a difference in America - and in the world.

Anything we can do in the near future that begins to stimulate the interest of people - seeing somebody down the street have an opportunity to go into space - buoys up the whole neighborhood.

There's a tremendously satisfying freedom associated with weightlessness. It's challenging in the absence of traction or leverage, and it requires thoughtful readjustment. I found the experience of weightlessness to be one of the most fun and enjoyable, challenging and rewarding, experiences of spaceflight. Returning to Earth brings with it a great sense of heaviness, and a need for careful movement. In some ways it's not too different from returning from a rocking ocean ship.

There are a lot of reasons for not doing something. And if humanity had come up with all the reasons for not doing something we wouldn't have spread across the Earth the way we have. There's a curiosity, and I would submit that that curiosity will put human beings on the surface of Mars.

My favourite thing to do on this planet is to scuba dive.

A hybrid human-robot mission to investigate an asteroid affords a realistic opportunity to demonstrate new technological capabilities for future deep-space travel and to test spacecraft for long-duration spaceflight.