“Curiosity is the essence of our existence.”

“I think America has a responsibility to maintain its leadership in technology and its moral leadership in the world, to explore, to seek knowledge.”

“When you head on out to the Moon, in very short order, and you get a chance to look back at the Earth, that horizon slowly curves around in upon himself, and all of sudden you're looking at something that is very strange, but yet is very, very familiar, because you're beginning to see the Earth evolve.”

“Here I am at the turn of the millennium and I'm still the last man to have walked on the moon, somewhat disappointing. It says more about what we have not done than about what we have done.”

“I do believe there is life in outer space. Mathematically, there has to be, and if you believe as I do that there is a creator of the universe, then how can we be so arrogant to believe he created life here and nowhere else?”

“Am I willing to go to Mars? Yes, but I'm not willing to spend nine months getting there, then wait 18 more months until the planets align to come home.”

“After Apollo 17, America stopped looking towards the next horizon. The United States had become a space-faring nation, but threw it away. We have sacrificed space exploration for space exploitation, which is interesting but scarcely visionary.”

“Today, we are on a path of decay. We are seeing the book close on five decades of accomplishment as the leader in human space exploration.”

“We found out the Gemini spacesuit was, well, oxygen was flowing to keep me cool as well as to breathe, and it wasn't good enough. My visor got fogged.”

“To become an astronaut, someone has to have a dream of his own to do something that he or she has always wanted to do, then commit himself to making that dream come true.”

“Curiosity is the essence of our existence.”