 What effect does Sattell's proximity have on Pop?
His name was Sattell and he had reason not to talk. There is nothing like it on Earth, of course. 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. 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. Sattell got the shakes when he thought of Pop, and Pop rather probably knew it. And Sattell turned gray and frantically denied that he'd ever seen Pop before. It seemed to Pop that the sight of Sattell had brought back some vague and cloudy memories. The pilot killed all forward motion just above the field and came steadily and smoothly down to land between the silvery triangles that marked the landing place. And a cover of insulating moondust with vacuum between the grains kept even air frozen solid, though in sunlight. He'd started to follow Sattell knowing what had happened to his wife and children, but it was hearsay only. 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. Even when Sattell—whimpering—signed up for Lunar City, Pop tracked him. The sun rose very, very slowly in what by convention was called the east. Near Sattell, he found memories of times when he was a young man with a young wife who loved him extravagantly. And when he was near Sattell he literally recovered them—in the sense that he came to know new things about them and had new memories of them every day. He simply wanted to be near him because it enabled him to recover new and vivid parts of his youth that had been lost. Otherwise, he was wholly matter-of-fact—certainly so for the far side of the Moon. At the same time, liquid air from another tank evaporated to maintain the proper air pressure in the shack. Sattell clearly remembered the crime Pop Young hadn't yet recalled.
 It restores Pop's memories of his wife and children
 It brings Pop's memory of the murder of his family into clarity  It motivates him to plot his revenge against his family's murderer  It amplifies the pain of his Pop's head injury  It restores Pop's memories of his wife and children