My first biography written in '73 was not 'Journey To The Moon.' It was 'Return To Earth.' Because for me, that was the more difficult task - disappointment.

Exploring and colonizing Mars can bring us new scientific understanding of climate change, of how planet-wide processes can make a warm and wet world into a barren landscape. By exploring and understanding Mars, we may gain key insights into the past and future of our own world.

Space is not just going up and coming back down again. Space is getting into orbit and being there, living there, establishing a presence, a permanence.

History gets reinterpreted as time goes on. Many times, the participants are lost in the retelling of the story.

I think I need to continue to think and plan and marry all of the different things that we could do that make transportation in space from the earth to the space station, from the earth to the moon to space stations around the moon to visiting an asteroid.

There's a need for accepting responsibility - for a person's life and making choices that are not just ones for immediate short-term comfort. You need to make an investment, and the investment is in health and education.

There's no doubt that there will be many trials and tribulations along the way in taming space for the benefit of all, unmasking its truths and using the boundless resources available to us. Taking a chance allows us to seek new horizons -- and we all benefit from being horizon hunters.