We want to explore. We’re curious people. Look back over history, people have put their lives at stake to go out and explore... We believe in what we’re doing. Now it’s time to go.

— Eileen Collins, STS-114 commander, a few days before the re-launch of the Space Shuttle program, reported on Space.com, 11 July 2005.

Of all investments into the future, the conquest of space demands the greatest efforts and the longest-term commitment . . . but it also offers the greatest reward: none less than a universe.

— Daniel Christlein

As we got further and further away, it (the Earth) dimished in size. Finally it shrank to the size of a marble, the most beautiful you can imagine. That beautiful, warm, living object looked so fragile, so delicate, that if you touched it with a finger it would crumble and fall apart. Seeing this has to change a man.

— James B. Irwin, Apollo 15.