IN THE BACKGROUND of Colorado Springs, Pikes Peak dominates the sky. But just to that mountain’s southeast looms another geological ripple. Cheyenne Mountain—a rounded, rocky thing that rises 9,565 feet above sea level—looks wild and quiet. But deep inside the mountain, a crew of humans toils in one of the nation’s most secure military installations. Shielded by 2,500 feet of granite, these people gather and analyze data from a global surveillance system, in an attempt to (among other, undisclosed things) warn the government’s highest officials of launches and missile threats to North America.