 What motivates Pop Young to live on the far side of the moon?
Once in two weeks Earth-time a rocketship came around the horizon from Lunar City with stores for the colony deep underground. The Crack, of course, was that gaping rocky fault which stretches nine hundred miles, jaggedly, over the side of the Moon that Earth never sees. When it was first found, scientists descended into it to examine the exposed rock-strata and learn the history of the Moon before its craters were made. Pop lived in it all alone, and in his spare time he worked industriously at recovering some missing portions of his life that Sattell had managed to take away from him. There were air-tight bulkheads for safety, and a hydroponic garden to keep the air fresh, and all sorts of things to make life possible for men under if not on the Moon. In the Moon's slight gravity, a man is really adjusted to existence when he has a well-developed case of agoraphobia. With such an aid, a man can get into a tiny, coffinlike cubbyhole, and feel solidity above and below and around him, and happily tell himself that it feels delicious. He'd shipped out, whimpering, to the Moon to get far away from Pop, and Pop was just about a mile overhead and there was no way to get around him. It doesn't take too long for the low gravity to tear a man's nerves to shreds. Even now there were some who had to be carried, but there were some tougher ones who were able to walk to the rocketship if Pop put a tarpaulin over their heads so they didn't have to see the sky. In any case Pop was essential, either for carrying or guidance. All of which happened back on Earth and a long time ago. There was a warning-bell in the shack, and when a rocketship from Lunar City got above the horizon and could send a tight beam, the gong clanged loudly, and Pop got into a vacuum-suit and went out the air lock. He usually reached the moondozer about the time the ship began to brake for landing, and he watched it come in. And a cover of insulating moondust with vacuum between the grains kept even air frozen solid, though in sunlight. At first Pop followed absorbedly from city to city, to recover the years that had been wiped out by an axe-blow. When Sattell fled to another continent, Pop followed because he had some distinct memories of his wife—and the way he'd felt about her—and some fugitive mental images of his children.
 He is close to Sattell's location, which enhances his memories of his wife and children
 He is being compensated for a wrongful death suit that occurred back on Earth  He is close to Sattell's location, which enhances his memories of his wife and children  If he left his post, there would be no one to monitor the mines in the Big Crack  If he returned to Earth, he would be arrested for the murder of his family