“Duster Two calling. This is it, I'm afraid. I've not reached Crater Lake yet; I'm still heading up the gorge. But the Observatory was right about the quake. There have been several slides, and we had difficulty in getting past some of them. There must be ten thousand tons of rock in the one I'm looking at now. If Selene's under that lot, we'll never find her. And it won't be worth the trouble of looking.”

The silence in Traffic Control lasted so long that the ski called back: “Hello, Traffic Control—did you receive me?”

“Receiving you,” said the Chief Engineer in a tired voice. “See if you can find some trace of them. I'll send Duster One in to help. Are you sure there's no chance of digging them out?”

“It might take weeks, even if we could locate them. I saw one slide three hundred meters long. If you tried to dig, the rock would probably start moving again.”

“Be very careful. Report every fifteen minutes, whether you find anything or not.”

Lawrence turned away from the microphone, physically and mentally exhausted. There was nothing more that he could do—or, he suspected, that anyone could do. Trying to compose his thoughts, he walked over to the southward-facing observation window, and stared into the face of the crescent Earth.

It was hard to believe that she was fixed there in the southern sky, that though she hung so close to the horizon, she would neither rise nor set in a million years. However long one lived here, one never really accepted this fact, which violated all the racial wisdom of mankind.

On the other side of that gulf (already so small to a generation that had never known the time when it could not be crossed), ripples of shock and grief would soon be spreading. Thousands of men and women were involved, directly or indirectly, because the Moon had stirred briefly in her sleep.

Lost in his thoughts, it was some time before Lawrence realized that the Port signals officer was trying to attract his attention.

“Excuse me, sir—you've not called Duster One. Shall I do it now?”

“What? Oh yes—go ahead. Send him to help Two in Crater Lake . Tell him we've called off the search in the Sea of Thirst .”

CHAPTER 6

The news that the search had been called off reached Lagrange II when Tom Lawson, red-eyed from lack of sleep, had almost completed the modifications to the hundred-centimeter telescope. He had been racing against time, and now it seemed that all his efforts had been wasted. Selene was not in the Sea of Thirst at all, but in a place where he could never have found her—hidden from him by the ramparts of Crater Lake, and, for good measure, buried by a few thousand tons of rock.

Tom's first reaction was not one of sympathy for the victims, but of anger at his wasted time and effort. Those YOUNG ASTRONOMER FINDS MISSING TOURISTS headlines would never flash across the news-screens of the inhabited worlds. As his private dreams of glory collapsed, he cursed for a good thirty seconds, with a fluency that would have astonished his colleagues. Then, still furious, he started to dismantle the equipment he had begged, borrowed, and stolen from the other projects on the satellite.

It would have worked; he was sure of that. The theory had been quite sound—indeed, it was based on almost a hundred years of practice. Infrared reconnaissance dated back to at least as early as World War II, when it was used to locate camouflaged factories by their telltale heat.

Though Selene had left no visible track across the Sea, she must, surely, have left an infrared one. Her fans had stirred up the relatively warm dust a foot or so down, scattering it across the far colder surface layers. An eye that could see by the rays of heat could track her path for hours after she had passed. There would have been just time, Tom calculated, to make such an infrared survey before the sun rose and obliterated all traces of the faint heat trail through the cold lunar night.

But, obviously, there was no point in trying now.

It was well that no one aboard Selene could have guessed that the search in the Sea of Thirst had been abandoned, and that the dust-skis were concentrating their efforts inside Crater Lake . And it was well, also, that none of the passengers knew of Dr. McKenzie's predictions.

The physicist had drawn, on a piece of homemade graph paper, the expected rise of temperature. Every hour he noted the reading of the cabin thermometer and pinpointed it on the curve. The agreement with theory was depressingly good; in twenty hours, one hundred ten degrees Fahrenheit would be passed, and the first deaths from heatstroke would be occurring. Whatever way he looked at it, they had barely a day to live. In these circumstances, Commodore Hansteen's efforts to maintain morale seemed no more than an ironic jest. Whether he failed or succeeded, it would be all the same by the day after tomorrow.