As soon as he had relocated Selene, Lawrence had started drilling again. On the monitor screen, Spenser could see the thin shaft of the oxygen-supply tube making its second descent into the dust. Why was Lawrence bothering to do this, he wondered, if he was not even sure whether anyone was still alive aboard Selene? And how was he going to check this, now that the radio had failed?
That was a question that millions of people were asking themselves as they watched the pipe sink down into the dust, and perhaps many of them thought of the right answer. Yet, oddly enough, it never occurred to anyone aboard Selene not even to the Commodore.
As soon as they heard that heavy thump against the roof, they knew at once that this was no sounding rod, delicately probing the Sea. When, a minute later, there came the unmistakable whirr of a drill chewing its way through Fiberglas, they felt like condemned men who had been granted a last-minute reprieve.
This time, the drill missed the cable conduit not that it mattered now. The passengers watched, almost hypnotized, as the grinding sound grew louder and the first flakes planed down from the ceiling. When the head of the drill appeared and descended twenty centimeters into the cabin, there was a brief but heartfelt burst of cheering.
Now what? said Pat to himself. We can't talk to them; how will I know when to unscrew the drill? I'm not going to make that mistake a second time.
Startlingly loud in this tense, expectant silence, the metal tube resonated with the DIT DIT DIT DAH which, surely, not one of Selene's company would forget, however long he lived. Pat replied at once, banging out an answering V with a pair of pliers. Now they know we're alive, he thought. He had never really believed that Lawrence would assume that they were dead and abandon them, yet at the same time there was always that haunting doubt.
The tube signaled again, this time much more slowly. It was a nuisance having to learn Morse; in this age, it seemed such an anachronism, and many were the bitter protests among pilots and space engineers at the waste of effort. In your whole lifetime, you might need it only once.
But that was the point. You would really need it then.
DIT DIT DAH, rapped the tube. DAH DIT.. DIT DIT DIT.. DAH DIT DAH DIT.. DIT DAH DIT.. DIT.. DIT DAH DAH.
Then, so that there would be no mistake, it started to repeat the word, but both Pat and the Commodore, rusty though they were, had got the message.
They're telling us to unscrew the drill, said Pat. Well, here we go.
The brief rush of air gave everyone a moment of unnecessary panic as the pressure equalized. Then the pipe was open to the upper world, and twenty-two anxious men and women waited for the first breath of oxygen to come gushing down it.
Instead, the tube spoke. Out of the open orifice came a voice, hollow and sepulchral, but perfectly clear. It was so loud, and so utterly unexpected, that a gasp of surprise came from the company. Probably not more than half a dozen of these men and women had ever heard a speaking tube; they had grown up in the belief that only through electronics could the voice be sent across space. This antique revival was as much a novelty to them as a telephone would have been to an ancient Greek.
This is Chief Engineer Lawrence speaking. Can you hear me?
Pat cupped his hands over the opening, and answered slowly: Hearing you loud and clear. How do you receive us?
Very clear. Are you all right?
Yes what's happened?
You've dropped a couple of meters no more than that. We hardly noticed anything up here, until the pipes came adrift. How's your air?
Still good but the sooner you start supplying us, the better.
Don't worry, we'll be pumping again as soon as we get the dust out of the filters, and can rush out another drill head from Port Roris. The one you've just unscrewed was the only spare; it was lucky we had that.
So it will be at least an hour, Pat told himself, before their air supply could be secured again. That, however, was not the problem that now worried him. He knew how Lawrence had hoped to reach them, and he realized that the plan would not work now that Selene was no longer on an even keel.
How are you going to get at us? he asked bluntly.
There was only the briefest of hesitations before Lawrence answered.
I've not worked out the details, but we'll add another section to the caisson and continue it down until it reaches you. Then we'll start scooping out the dust until we get to the bottom. That will take us to within a few centimeters of you; we'll cross that gap somehow. But there's one thing I want you to do first.
What's that?
I'm ninety per cent sure that you won't settle again but if you're going to, I'd rather you did it now. I want you all to jump up and down together for a couple of minutes.
Will that be safe? asked Pat doubtfully. Suppose this pipe tears out again?
Then you can plug it again. Another small hole won't matter but another subsidence will, if it happens when we're trying to make a man-sized opening in the roof.
Selene had seen some strange sights, but this was undoubtedly the strangest. Twenty-two men and women were solemnly jumping up and down in unison, rising to the ceiling and then pushing themselves back as vigorously as possible to the floor. All the while Pat kept a careful watch on that pipe leading to the upper world; after a minute's strenuous exertion on the part of her passengers, Selene had moved downward by less than two centimeters.
He reported this to Lawrence, who received the news with thankfulness. Now that he was reasonably sure that Selene would not shift again, he was confident that he could get these people out. Exactly how, he was not yet certain, but the plan was beginning to form in his mind.
It took shape over the next twelve hours, in conferences with his brains trust and experiments on the Sea of Thirst. The Engineering Division had learned more about the dust in the last week than during the whole of its previous existence. It was no longer fighting in the dark against a largely unknown opponent. It understood which liberties could be taken, and which could not.
Despite the speed with which the changed plans were drawn up and the necessary hardware constructed, there was no undue haste and certainly no carelessness. For this was another operation that had to work the first time. If it failed, then at the very least the caisson would have to be abandoned and a new one sunk. And at the worst those aboard Selene would be drowned in dust.
It's a pretty problem, said Tom Lawson, who liked pretty problems and not much else. The lower end of the caisson's wide open to the dust, because it's resting against Selene at only one point, and the tilt of the roof prevents it from sealing. Before we can pump out the dust, we have to close that gap.
Did I say 'pump'? That was a mistake. You can't pump the stuff; it has to be lifted. And if we tried that as things are now, it would flow in just as fast at the bottom of the tube as we took it out of the top.
Tom paused and grinned sardonically at his multimillion audience, as if challenging it to solve the problem he had outlined. He let his viewers stew in their own thoughts for a while, then picked up the model lying on the studio table. Though it was an extremely simple one, he was rather proud of it, for he had made it himself. No one could have guessed, from the other side of the camera, that it was only cardboard sprayed with aluminum paint.
This tube, he said, represents a short section of the caisson that's now leading down to Selene and which, as I said, is full of dust. Now this with his other hand, he picked up a stubby cylinder, closed at one end fits snugly inside the caisson, like a piston. It's very heavy, and will try to sink under its own weight. But it can't do so, of course, while the dust is trapped underneath it.