carrying it headlong into the depths. There was nothing he could do but attempt to keep on an even keel, and to hope that their speed would carry them up the far side of the crater before it collapsed upon them.
If the passengers screamed or cried out, Pat never heard them. He was conscious only of that dreadful, sickening slide, and of his own attempts to keep the cruiser from capsizing. Yet even as he fought with the controls, feeding power first to one fan, then to the other, in an effort to straighten Selene's course, a strange, nagging memory was teasing his mind. Somewhere, somehow, he had seen this happen before.
That was ridiculous, of course, but the memory would not leave him. Not until he reached the bottom of the funnel and saw the endless slope of dust rolling down from the crater's star-fringed lip did the veil of time lift for a moment.
He was a boy again, playing in the hot sand of a forgotten summer. He had found a tiny pit, perfectly smooth and symmetrical, and there was something lurking in its depths—something completely buried except for its waiting jaws. The boy had watched, wondering, already conscious of the fact that this was the stage for some microscopic drama. He had seen an ant, mindlessly intent upon its mission, stumble at the edge of the crater and topple down the slope.
It would have escaped easily enough—but when the first grain of sand had rolled to the bottom of the pit, the waiting ogre had reared out of its lair. With its forelegs, it had hurled a fusillade of sand at the struggling insect, until the avalanche had overwhelmed it and brought it sliding down into the throat of the crater.
As Selene was sliding now. No ant lion had dug this pit on the surface of the Moon, but Pat felt as helpless now as that doomed insect he had watched so many years ago. Like it, he was struggling to reach the safety of the rim, while the moving ground swept him back into the depths where death was waiting. A swift death for the ant, a protracted one for him and his companions.
The straining motors were making some headway, but not enough. The falling dust was gaining speed—and, what was worse, it was rising outside the walls of the cruiser. Now it had reached the lower edge of the windows; now it was creeping up the panes; and at last it had covered them completely. Pat cut the motors before they tore themselves to pieces, and as he did so, the rising tide blotted out the last glimpse of the crescent Earth. In darkness and in silence, they were sinking into the Moon.
CHAPTER 3
In the banked communications racks of Traffic Control, Earthside North, an electronic memory stirred uneasily. The time was one second past twenty hundred hours GMT: a pattern of pulses that should arrive automatically on every hour had failed to make its appearance.
With a swiftness beyond human thought, the handful of cells and microscopic relays looked for instructions. “WAIT FIVE SECONDS,” said the coded orders. “IF NOTHING HAPPENS, CLOSE CIRCUIT 10011001.”
The minute portion of the traffic computer as yet concerned with the problem waited patiently for this enormous period of time—long enough to make a hundred million twenty-figure additions, or to print most of the contents of the Library of Congress. Then it closed circuit 10011001.
High above the surface of the Moon, from an antenna which, curiously enough, was aimed directly at the face of the Earth, a radio pulse launched itself into space. In a sixth of a second it had flashed the fifty thousand kilometers to the relay satellite known as Lagrange II, directly in the line between Moon and Earth. Another sixth of a second and the pulse had returned, much amplified, flooding Earthside North from pole to equator.
In terms of human speech, it carried a simple message. “HELLO, SELENE,” the pulse said. “I AM NOT RECEIVING YOUR BEACON. PLEASE REPLY AT ONCE.”
The computer waited for another five seconds. Then it sent out the pulse again, and yet again. Geological ages had passed in the world of electronics, but the machine was infinitely patient.
Once more, it consulted its instructions. Now they said: “CLOSE CIRCUIT 10101010.” The computer obeyed. In Traffic Control, a green light flared suddenly to red, a buzzer started to saw the air with its alarm. For the first time, men as well as machines became aware that there was trouble, somewhere on the Moon.
The news spread slowly at first, for the Chief Administrator took a very poor view of unnecessary panic. So, still more strongly, did the Tourist Commissioner; nothing was worse for business than alerts and emergencies— even when, as happened in nine cases out of ten, they proved to be due to blown fuses, tripped cutouts, or oversensitive alarms. But on a world like the Moon, it was necessary to be on one's toes. Better be seared by imaginary crises than fail to react to real ones.
It was several minutes before Commissioner Davis reluctantly admitted that this looked like a real one. Selene's automatic beacon had failed to respond on one earlier occasion, but Pat Harris had answered as soon as he had been called on the cruiser's assigned frequency. This time, there was silence. Selene had not even replied to a signal sent out on the carefully guarded MOONCRASH band, reserved solely for emergencies. It was this news that brought the Commissioner hurrying from the Tourist Tower along the buried glideway into Clavius City .
At the entrance to the Traffic Control center, he met the Chief Engineer, Earthside. That was a bad sign; it meant that someone thought that rescue operations would be necessary. The two men looked at each other gravely, each obsessed by the same thought.
“I hope you don't need me,” said Chief Engineer Lawrence. “Where's the trouble? All I know is that a Mooncrash signal's gone out. What ship is it?”
“It's not a ship. It's Selene; she's not answering, from the Sea of Thirst .”
“My God—if anything's happened to her out there, we can only reach her with the dust-skis. I always said we should have two cruisers operating, before we started taking out tourists.”
“That's what I argued—but Finance vetoed the idea. They said we couldn't have another until Selene proved she could make a profit.”
“I hope she doesn't make a headline instead,” said Lawrence grimly. “You know what I think about bringing tourists to the Moon.”
The Commissioner did, very well; it had long been a bone of contention between them. For the first time, he wondered if the Chief Engineer might have a point.
It was, as always, very quiet in Traffic Control. On the great wall maps, the green and amber lights flashed continuously, their routine messages unimportant against the clamor of that single, flaring red. At the Air, Power, and Radiation consoles, the duty officers sat like guardian angels, watching over the safety of one quarter of a world.
“Nothing new,” reported the Ground Traffic officer. “We're still completely in the dark. All we know is that they're somewhere out in the Sea.”
He traced a circle on the large-scale map.
“Unless they're fantastically off course, they must be in that general area. On the nineteen hundred hours check, they were within a kilometer of their planned route. At twenty hundred, their signal had vanished, so whatever happened took place in that sixty minutes.”
“How far can Selene travel in an hour?” someone asked.
“Flat out, a hundred and twenty kilometers,” replied the Commissioner. “But she normally cruises at well under a hundred. You don't hurry on a sight-seeing tour.”
He stared at the map, as if trying to extract information from it by the sheer intensity of his gaze.
“If they're out in the Sea, it won't take long to find them. Have you sent out the dust-skis?”
“No, sir; I was waiting for authorization.”
Davis looked at the Chief Engineer, who outranked anyone on this side of the Moon except Chief Administrator Olsen himself. Lawrence nodded slowly.
“Send them out,” he said. “But don't expect results in a hurry. It will take awhile to search several thousand square kilometers—especially at night. Tell them to work over the route from the last reported position, one ski on either side of it, so that they sweep the widest possible band.”
When the order had gone out, Davis asked unhappily: “What do you think could have happened?”
“There are only a few possibilities. It must have been sudden, because there was no message from them. That usually means an explosion.”
The Commissioner paled; there was always the chance of sabotage, and no one could ever guard against
