On the fourth floor of the Launch Control Center, a NASA official began leading the wives and children out of Thomas’s office, down the hallway, past rows of cubicles, and out through a heavy self-closing door. One by one, they stepped out on to the roof and mounted the big steel staircase to the very top of the building: a broad expanse of pale concrete the size of a football field, surrounded by a white railing that cast a crisp shadow in the winter sunshine.
