When Apollo 11‘s Eagle lunar module landed on the moon on July 20, 1969, astronauts Neil Armstrong and Buzz Aldrin had to do something hard: Wait. They were scheduled to open the door of their lunar lander and step onto the unknown surface of a completely different world. But for now, their mission ordered them to take a pause before the big event. And so Aldrin spent his time doing something unexpected, something no man had ever attempted before. Alone and overwhelmed by anticipation, he took part in the first Christian sacrament ever performed on the moon—a rite of Christian...