In the mid-20th century, a routine mission to the moon resulted in an unmanned rocket missing its mark and tumbling toward the sun. The rocket was presumed lost. Life went on. A century later, the rocket came back. Believed at first to be a piece of space debris, it was soon confirmed to match the description of the ship from the long-lost moon mission. It looks like our rocket, it feels like our rocket, but it is not our rocket. What is it? How did...