"Hell, lots of reasons, Julius. You can't get a whole relief crew and let them take over cold. They have to know where you left off. They have to know where things are, how things work, what to watch out for. And then, because you've been here a year and a half and know the ropes, you have to watch them to see that they stay alive in spite of themselves. The Moon's a new environment and you have to learn how to live in it. There's a lot of things to learn--and some people just never learn." "You're nursemaid, then." "I suppose you could call it that." * * * * * Klein said, "You're not a scientist, are you?" "No, you should know that. I came as the pilot of the first ship. We made the bunker out of parts of the ship so there wasn't anything to go back on. I'm a good mechanic and I made myself useful with the machinery. When it occurred to us that somebody was going to have to stay over, I volunteered. I thought the others were so important that it was better they should take their samples and data back to Earth when the first relief ship came." "You wouldn't do it again, though, would you?" "No, I wouldn't." "Do you think Dahl will do as good a job as you've done here?" Chapman frowned. "Frankly, I hadn't thought of that. I don't believe I care. I've put in my time; it's somebody else's turn now. He volunteered for it. I think I was fair in explaining all about the job when you talked it over among yourselves." "You did, but I don't think Dahl's the man for it. He's too young, too much of a kid. He volunteered because he thought it made him look like a hero. He doesn't have the judgment that an older man would have. That you have." Chapman turned slowly around and faced Klein. "I'm not the indispensable man," he said slowly, "and even if I was, it wouldn't make any difference to me. I'm sorry if Dahl is young. So was I. I've lost three years up here. And I don't intend to lose any more." Klein held up his hands. "Look, Chap, I didn't mean you should stay. I know how much you hate it and the time you put in up here. It's just--" His voice trailed away. "It's just that I think it's such a damn important job." Klein had gone out in a last search for rock lichens and Chapman enjoyed one of his relatively few moments of privacy. He wandered over to his bunk and opened his barracks bag. He checked the underwear and his toothbrush and shaving kit for maybe the hundredth time and pushed the clothing down farther in the canvas. It was foolish because the bag was already packed and had been for a week. He remembered stalling it off for as long as he could and then the quiet satisfaction about a week before, when he had opened his small gear locker and transferred its meager belongings to the bag.