In May 1961, President Kennedy announced that the United States would attempt to land a man on the moon and return him safely to the earth before the end of that decade. Yet NASA did not have a specific plan for how to accomplish that goal. Over the next fourteen months, NASA vigorously debated several options. At first the consensus was to send one big rocket with several astronauts to the moon, land and explore, and then take off and return the astronauts to earth in the same vehicle. Another...