"Houston... Tranquility Base here... the Eagle has landed." And with those words, mankind changed forever. We were no longer bound to one planet, one place, troglodytes adhering to the surface of Earth. We became a space-dwelling species. Future historians will divide humanity's time on Earth into two eras, and the demarcation between them was that moment. Five more times we'd go to the Moon. The next four decades were spent in low-Earth orbit, limited circles with an inevitable return to the bottom of the gravity well. But we can't help looking up, looking out, toward the stars. We've already begun our preparation to return to where we need to go, to space, to the Moon, to the planets. We're still arguing over how to do it, and even if we should. But I know we will. We have to. Millions of years of evolutionary pressure have made us explorers, engraving the need to seek things out in our genes and in our brains. We'll go back. We'll go to stay, and settle, and then move out again. The sky is full of places to go, enough to satisfy the needs and desires of a thousand generations. It's just a matter of time. Happy anniversary, Apollo 11. And we thank you.