In 1968, the Apollo 8 crew of Lovell, Frank Borman and William Anders was the first to leave Earth's orbit and the first to fly to and circle the moon. They could not land, but they put the U.S. ahead of the Soviets in the space race. During the harrowing Apollo 13 flight in April 1970, Lovell was supposed to be the fifth man to walk on the moon. But Apollo 13's service module, carrying Lovell and two others, experienced a sudden oxygen tank explosion on its way to the moon. The astronauts barely survived, spending four cold and clammy...