Every couple of years, we could dispatch people from Earth to Mars.

The pilgrims on the Mayflower landed at Plymouth Rock. To my knowledge, they didn't wait around for a return trip to Europe. You settle some place with a purpose. If you don't want to do that, stay home. You avoid an awful lot of risks by not venturing outward.

There's no guarantee that the United States will be around 200 years from now.

Globalisation means many other countries are asserting themselves and trying to take over leadership. Please don't ask Americans to let others assume the leadership of human exploration. We can do wonderful science on the Moon, and wonderful commercial things. Then we can pack up and move on to Mars.

The urge to explore has propelled evolution since the first water creatures reconnoitered the land. Like all living systems, cultures cannot remain static; they evolve or decline. They explore or expire. . . . Beyond all rationales, space flight is a spiritual quest in the broadest sense, one promising a revitalization of humanity and a rebirth of hope no less profound than the great opening out of mind and spirit at the dawn of our modern age.

The moon I see now is the same moon I saw before. Except that before, when I looked at it, it was in anticipation of what it would be like when I got there. That's behind me now.

As we reflect back upon the tragic loss of Challenger and her brave crew of heroes who were aboard that fateful day, I am reminded that they truly represented the best of us, as they climbed aloft on a plume of propellant gasses, reaching for the stars, to inspire us who were Earthbound.