“Will we be able to go into the nucleus?”
“We’ll know when we get there. Maybe we’ll play safe and study it through telescopes from a few thousand miles away. But personally, I’ll be disappointed unless we go right inside. Won’t you?”
Pickett switched off the recorder. Yes, Martens had been right. He would have been disappointed, especially since there had seemed no possible source of danger. Nor was there, as far as the comet was concerned. The danger had come from within.
They had sailed through one after another of the huge but unimaginably tenuous curtains of gas that Randall’s comet was still ejecting as it raced away from the sun. Yet even now, though they were approaching the densest regions of the nucleus, they were for all practical purposes in a perfect vacuum. The luminous fog that stretched around Challenger for so many millions of miles scarcely dimmed the stars; but directly ahead, where lay the comet’s core, was a brilliant patch of hazy light, luring them onwards like a will-o’-the-wisp.
The electrical disturbances now taking place around them with ever-increasing violence had almost completely cut their link with Earth. The ship’s main radio transmitter could just get a signal through, but for the last few days they had been reduced to sending “O.K.” messages in Morse. When they broke away from the comet and headed for home, normal communication would be resumed; but now they were almost as isolated as explorers had been in the days before radio. It was inconvenient, but that was all. Indeed, Pickett rather welcomed this state of affairs; it gave him more time to get on with his clerical duties. Though Challenger was sailing into the heart of a comet, on a course that no captain could have dreamed of before the twentieth century, someone still had to check the provisions and count the stores.
Very slowly and cautiously, her radar probing the whole sphere of space around her, Challenger crept into the nucleus of the comet. And there she came to rest—amid the ice.
Back in the nineteen-forties, Fred Whipple, of Harvard, had guessed the truth, but it was hard to believe it even when the evidence was before one’s eyes. The comet’s relatively tiny core was a loose cluster of icebergs, drifting and turning round one another as they moved along their orbit. But unlike the bergs that floated in polar seas, they were not a dazzling white, nor were they made of water. They were a dirty grey, and very porous, like partly thawed snow. And they were riddled with pockets of methane and frozen ammonia, which erupted from time to time in gigantic gas jets as they absorbed the heat of the sun. It was a wonderful display, but Pickett had had little time to admire it. Now he had far too much.
He had been doing his routine check of the ship’s stores when he came face to face with disaster—though it was some time before he realized it. For the supply situation had been perfectly satisfactory; they had ample stocks for the return to Earth. He had checked that with his own eyes, and now had merely to confirm the balances recorded in the pinhead-sized section of the ship’s electronic memory which stored all the accounts.
When the first crazy figures flashed on the screen, Pickett assumed that he had pressed the wrong key. He cleared the totals, and fed the information into the computer once more.
Sixty cases of pressed meat to start with; 17 consumed so far; quantity left: 99999943.
He tried again, and again, with no better result. Then, feeling annoyed but not particularly alarmed, he went in search of Dr Martens.
He found the astronomer in the Torture Chamber—the tiny gym, squeezed between the technical stores and the bulkhead of the main propellant tank. Each member of the crew had to exercise here for an hour a day, lest his muscles waste away in this gravityless environment. Martens was wrestling with a set of powerful springs, an expression of grim determination on his face. It became much grimmer when Pickett gave his report.
A few tests on the main input board quickly told them the worst. “The computer’s insane,” said Martens. “It can’t even add or subtract.”
“But surely we can fix it!”
Martens shook his head. He had lost all his usual cocky self-confidence; he looked, Pickett told himself, like an inflated rubber doll that had started to leak.
“Not even the builders could do that. It’s a solid mass of microcircuits, packed as tightly as the human brain. The memory units are still operating, but the computing section’s utterly useless. It just scrambles the figures you feed into it.”
“And where does that leave us?” Pickett asked.
“It means that we’re all dead,” Martens answered flatly. “Without the computer, we’re done for. It’s impossible to calculate an orbit back to Earth. It would take an army of mathematicians weeks to work it out on paper.”
“That’s ridiculous! The ship’s in perfect condition, we’ve plenty of food and fuel—and you tell me we’re all going to die just because we can’t do a few sums.”
“A few sums!” retorted Martens, with a trace of his old spirit. “A major navigational change, like the one needed to break away from the comet and put us on an orbit to Earth involves about a hundred thousand separate calculations. Even the computer needs several minutes for the job.”
Pickett was no mathematician, but he knew enough of astronautics to understand the situation. A ship coasting through space was under the influence of many bodies. The main force controlling it was the gravity of the sun, which kept all the planets firmly chained in their orbits. But the planets themselves also tugged it this way and that, though with much feebler strength. To allow for all these conflicting tugs and pulls—above all, to take advantage of them to reach a desired goal scores of millions of miles away—was a problem of fantastic complexity. He could appreciate Martens’ despair; no man could work without the tools of his trade, and no trade needed more elaborate tools than this one.
Even after the Captain’s announcement, and that first emergency conference when the entire crew had gathered to discuss the situation, it had taken hours for the facts to sink home. The end was still so many months away that the mind could not grasp it; they were under sentence of death, but there was no hurry about the execution. And the view was still superb…
Beyond the glowing mists that enveloped them—and which would be their celestial monument to the end of time—they could see the great beacon of Jupiter, brighter than all the stars. Some of them might still be alive, if the others were willing to sacrifice themselves, when the ship went past the mightiest of the sun’s children. Would the extra weeks of life be worth it, Pickett asked himself, to see with your own eyes the sight that Galileo had first glimpsed through his crude telescope four centuries ago—the satellites of Jupiter, shuttling back and forth like beads upon an invisible wire?
Beads upon a wire. With that thought, an all-but-forgotten childhood memory exploded out of his subconscious. It must have been there for days, struggling upward into the light. Now at last it had forced itself upon his waiting mind.
“No!” he cried aloud. “It’s ridiculous! They’ll laugh at me!”
So what? said the other half of his mind. You’ve nothing to lose; if it does no more, it will keep everyone busy while the food and the oxygen dwindle away. Even the faintest hope is better than none at all…
He stopped fidgeting with the recorder; the mood of maudlin self-pity was over. Releasing the elastic webbing that held him to his seat, he set off for the technical stores in search of the materials he needed.
“This,” said Dr Martens three days later, “isn’t my idea of a joke.” He gave a contemptuous glance at the flimsy structure of wire and wood that Pickett was holding in his hand.