 What do the colony inhabitants share?
The shack and the job he filled were located in the medieval notion of the physical appearance of hell. By night—lunar night, of course, and lunar day—it was frigidity and horror. Once in two weeks Earth-time a rocketship came around the horizon from Lunar City with stores for the colony deep underground. Come nightfall Pop lowered the supplies down the long cable into the Big Crack to the colony far down inside, and freshened up the landing field marks with magnesium marking-powder if a rocket-blast had blurred them. There is nothing like it on Earth, of course. 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. They found the reason for the colony and the rocket landing field and the shack. The outside was surface moondust, piled over a tiny dome to be insulation against the cold of night and shadow and the furnace heat of day. 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. 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. All of which happened back on Earth and a long time ago. And a cover of insulating moondust with vacuum between the grains kept even air frozen solid, though in sunlight. 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. When Sattell frenziedly tried to deny knowledge of the murder in Tangier, Pop had come to remember both his children and some of the happiness of his married life. In each two Earth-weeks of working, the mine-colony nearly filled up a three-gallon cannister with greasy-seeming white crystals shaped like two pyramids base to base. But on Earth its contents would be computed in carats, and a hundred pounds was worth millions. The sun rose very, very slowly in what by convention was called the east. He simply wanted to be near him because it enabled him to recover new and vivid parts of his youth that had been lost. At the same time, liquid air from another tank evaporated to maintain the proper air pressure in the shack.
 fear of open spaces
 traumatic brain injuries  criminal backgrounds  fear of open spaces  aversion to sunlight