It was immediately pointed out that to be probed by a laser beam, even though the damage was restricted to an area only a few inches across, might be regarded as an unfriendly act. So Bowman had been directed to use the instrument only if he was satisfied, beyond all reasonable doubt, that he was not aiming it at an inhabited body.
He had rather mixed feelings about the device. Although he approved of the expedition's "no weapons" policy, he could easily imagine circumstances when the laser spectrograph's nonscientific applications might be more than useful. It was reassuring to know that they were not completely defenseless.
JUPITER V
Moving more and more slowly as she approached the far point of her ellipse, Discovery soared past the orbits of Ganymede and Callisto-but they were out of range on the other side of Jupiter. The ship began to fall back, cutting again across their orbits, as well as those of Europa and Io. She was about to make her first approach to the closest and in some ways oddest of all the satellites, tiny Jupiter V.
Only seventy thousand miles above the turbulent Jovian cloudscape, and completing each orbit in less than twelve hours, Jupiter V is the nearest thing to a natural synchronous satellite in the whole Solar System. For as Jupiter revolves in about ten hours, V stands almost still in its sky, drifting very slowly indeed from east to west.
It was not easy to observe Jupiter V. The tiny moonlet, only a hundred miles in diameter, was so close to Jupiter that it spent much of its time eclipsed in the planet's enormous cone of shadow. And even when it was in the sunlight, it moved so rapidly that it was hard to find and to keep in the field of view.
The fly-by on the morning of that second Joveday was not very favorable, the satellite was twenty thousand miles away, and visible only for about ten minutes. There was time for nothing more than a quick look through the telescopes, while the cameras snapped a few hundred shots of the rapidly vanishing little world.
The detailed examination of the photos would take several hours; after a while the endless repetition of impact craters, fractured rocks, and occasional patches of frozen gas produced something close to boredom. But no one could tear himself away from the screen; and at last, after more than half the stored images had been scanned, patience was rewarded.
The crucial sequence had been taken with a telephoto lens, just as Jupiter V was emerging from shadow. At one moment there was a black screen; then, magically, a thin crescent suddenly materialized, as the little moon came out of eclipse.
Kimball was the first to spot the curious oval patch near the terminator. He froze the picture, and zoomed in for full magnification. As he did so, there were simultaneous gasps from all his colleagues.
Part of the side facing Jupiter had been sheared off flat, as if by a cosmic bulldozer, leaving a perfectly circular plateau several miles across. At its center was a clear-cut, sharply defined rectangle, about five times as long as it was wide, and pitch-black. At first glance it seemed to be a solid object; then they realized that they were staring into shadow; this was an enormous hole or slot, wide enough to engulf Discovery, and extending deep into the heart of Jupiter V. It was at least a quarter of a mile in length, and perhaps a hundred yards wide.
Time and geology could play some odd tricks with a world; but this was not one of them.
It was an unusually quiet and subdued group that gathered in the artificial gravity of the carousel for the luxury of coffee that could actually be drunk from cups, not squirted from plastic bulbs.
The wonder and the excitement of the discovery had already passed, to be replaced by more somber feelings. What until now had been only a possibility-and, to tell the truth, rather a remote one-had suddenly become an awesome reality. That pyramid on the Moon had been astonishing, but it was only a tiny thing. This was something altogether different-a whole world with a slice carved off, just as one may behead an egg with a knife.
"We're up against a technology," said Bowman soberly, "that makes us look like children building sandcastles on the beach."
"Well," answered Kaminski, "we suspected that from the beginning. Now the big question is-are they still here?"
Jupiter V looked utterly lifeless, but an entire civilization could exist, miles below the surface, at the bottom of that rectangular chasm. The creatures who put TMA-1 on the Moon, three million years ago, could still be going about their mysterious business.
Perhaps they had already observed Discovery, and knew all about this mission. They might be totally uninterested in the primitive spacecraft orbiting at their threshold; or they might be biding their time.
FINAL ORBIT
This was the situation classified in the mission profile as "Evidence of intelligent life-no sign of activity," and the response had been outlined in detail. They would do nothing for ten days except transmit the prime numbers 1 . . . 2 . . . 3 . . . 5 . . . 7 . . . 11 . . . 13 . . . 17, at intervals of two minutes, over a broad band of the radio spectrum. Luckily, the loss of the main antenna complex did not affect this operation; the low-powered equipment on the Control Deck was quite adequate for such short-range work.
They called, and they listened on all possible frequencies; but there was no reply. Though this could indicate many things, it began to seem more and more likely that the tiny moonlet was abandoned. It was hard to believe that it could ever have been anything except a temporary encampment for an expedition-from Jupiter itself, or from the stars?
While they were waiting and watching, and continuing to survey the other four moons whenever the opportunity arose, Bowman prepared for the next step. If it was physically possible, Discovery would make a rendezvous with Jupiter V.
Kaminski spent hours considering approach orbits; Athena spent seconds computing them. The maneuver was a very difficult one, for though Jupiter V's own gravity was negligible, the satellite was trapped deep in Jupiter's enormous gravitational field. Discovery would have to make a speed change of over twenty thousand miles an hour to match orbits and achieve a rendezvous.
It could just be done-and, ironically, only the earlier disasters made it possible. The ship was more than a ton lighter than expected at this stage of the mission, for it had lost two crew members, a spacepod, and the antenna complex. That was enough to make the difference between a maneuver that was barely feasible, and one which had a good safety margin.
Once Discovery had entered the parking orbit around Jupiter V, she could never leave it; her propellant reserves would be completely exhausted. And though the recovery ship would hardly expect to find her here, it would soon spot her radio beacon and her flashing strobe lights. Nuclear batteries would power them for twenty years; their detectable range was only about a million miles, but that was ample.
As soon as he was sure of the calculations, Bowman wasted no more time. The ten days were up: Jupiter V was still silent. The mission profile said: "Proceed with caution-in the event of hostility, withdraw."
That was excellent advice-except that retreat would be impossible. Once they had used their final reserves, they would be wholly committed.
After more than fifty orbits of Jupiter V, they had mapped and inspected its entire surface, most of which was covered with an icy rime of frozen ammonia. There was no sign of life, no hint of any activity. A search for radio emissions or electrical interference was fruitless; the little moon appeared to be completely dead. The theory that it was some kind of abandoned base, perhaps even a deserted city-world that ages ago had come here from some other solar system, slowly gained ground. Hunter was its chief advocate; when asked where he thought the hypothetical star- people had gone, he answered: "I think they were our ancestors." He was more than half serious about this, and refused to budge in the face of all the anthropological and geological evidence that could be thrown at him.
On the fourth day they dropped two of the ship's soft-landing probes-one on Kimball's Plain, the other at its antipodes. The radioed reports were inconclusive: the seismographs could detect no tremors-the sensitive geophones, not a whisp
er of internal sound. As far as the instruments could tell, Jupiter V was a dead lump of rock.
After two more days of waiting to see if anything had emerged to investigate the probes, Bowman made his decision. The others had been expecting it; from time to time, each had quietly hinted to Bowman that he should be the one to make the first reconnaissance.
In the carousel lounge, which had once seemed so small but was now, alas, larger than they required, he outlined the plan.
"We have only two pods," Bowman began, "and I'm going to commit them both: I think it will be safer that way. If one gets in trouble, the other will be there to help.
"Two pods will go down to the surface; one will stay on the brink of the chasm and the other will go in for a distance of not more than a thousand meters-less, if there's the slightest sign of danger. I'll take the forward one; Jack will be my Number Two."
At this, there were groans from Kaminski and Hunter; Bowman smiled and shook his head firmly.
"You have to stay behind and run the ship. If we don't come back, there's absolutely nothing you can do to help us. Your job is to watch, record what happens, and see that Earth gets the story-even if it's five years from now."
He listened patiently while Hunter and Kaminski pressed their superior claims, but he had already made up his mind. They were all equally qualified, but Kimball had discovered this place, and it now bore his name. It was only fair that he should be first to set foot on it.
Within an hour, the airlocks opened and the two little pods jetted themselves slowly out into space. After a few seconds of careful braking, they had checked their orbital speed, and Discovery was pulling away from them at her regular two hundred miles an hour. They were falling free, in the weak gravity field of Jupiter V. Their tenthousand-foot drop here was equivalent to a fall of less than a hundred feet on earth; they could wait until they were quite close to the surface before attempting to brake.
After a one-minute hover at a thousand feet, Bowman gave the signal for the final descent. There were no landing problems on this utterly flat plain, and he had decided to come down within a hundred yards of the pit. A last burst of power canceled the space pod's five or six pounds of weight, and he hovered for a second to give Kimball the privilege of landing first. Then he touched down on Jupiter V with scarcely a bump.
He glanced out of the port, saw that Kimball was O.K., and called the ship.
"Bowman to Discovery. Landed on Jupiter V. Can you read me?"
The answer, as he had expected, was already fading. In the few minutes of their descent, the ship's orbit had taken it down to the horizon, and was dropping below the edge of the satellite.
"Discovery to Bowman. Message received but signal strength fading. Good luck. Will listen out and call you in ninety minutes."
"Roger."
Discovery was gone-not yet twenty miles away, but out of reach. It was true that she would be back again, by the inexorable laws of celestial mechanics, in just one and a half hours as she came up over the opposite horizon of this tiny world. That knowledge was some help, but not as much as they would have liked, to a pair of lonely men faced with a three-million-year-old enigma
Jetting the pod twenty feet off the surface, Bowman aimed toward the opening of the pit. As he approached that dark, gaping cavity, he suddenly remembered a childhood impression. When he was about ten years old, his father had taken him to the Grand Canyon, and the shock of first seeing that stupendous wound on the face of the earth had left a permanent imprint on his mind. The rectangular cleft toward which he was now drifting was tiny by comparison-but in this setting, on this desolate world, with the ominous half-moon of Jupiter hanging forever fixed in the inky sky-it seemed as awe-inspiring as the Grand Canyon. More so, indeed, for it was far deeper, and he could not guess what it concealed.
He brought the pod to rest a few feet from the brink, and surveyed the smooth, polished walls converging into the depth. The far walls were brilliant in the light of the sun, which ended abruptly in a slashing line of shadow about four hundred feet down. The feebler light of Jupiter, shining straight into the cleft, seemed to lose its power at a distance which Bowman could not even guess. Their was no sign of a bottom; the pit was like a classical exercise in perspective, all its parallel lines meeting at infinity. He tied the small, portable light which hooked onto the side of his space pod to his safety line, and let it fall the full length of the thousand meters. It took three minutes of uncannily slow-motion descent for the line to become taut; then the lamp was a bright star far down against the face of the shadowed wall. It had encountered no obstacles, provoked no reaction. Jupiter V had maintained its usual indifference.
Bowman suddenly decided that he had been cautious long enough. Not only were they running out of time, but there was only limited fuel for the pods. They had to make every minute count.
"I'm going in," he told Kimball. "I won't go further than the end of your safety line. Haul me out when I give the signal-or if I don't answer when you call me."
He could have made a free fall and come back on the jets, but there was no need to waste precious fuel. Kimball could reel him back without difficulty, for the safety line would have an apparent weight of only about five pounds at its end.
"Keep talking all the way, skipper," said Kimball. "It's kinda lonely up here."
Bowman was perfectly willing to comply. No matter how accustomed one became to low gravity, the ingrained responses of a million terrestrial ancestors died hard. He had to keep reminding himself that this pit in which he was dangling was not a miles-deep shaft on earth, down which he could go crashing to destruction if the slim thread of the safety line snapped. Though there might be danger here, it was not from gravity, and he must ignore the insistent warnings of his instincts.
"I must be two hundred feet down now," he said to Kimball. "Keep lowering me at the same rate-there's nothing to see yet, but I'll get a better view as soon as I'm out of the sunlight. Radiation count still negligible. There goes the sun-now I'm in the shadow, but there's still plenty of light from Jupiter. Still no sign of a bottom- this thing must be at least five miles deep-I feel like an ant crawling down a chimney-HELLO . . . !"
His voice trailed off in sudden excitement.
"What is it? Do you see something?" Kimball demanded.
"Yes-I think so. Now I'm out of the glare, my eyes are getting more sensitive. There's a light down there- a very dim one-a hell of a long way off. Just a minute while I unship the telescope."
There were sounds of heavy breathing and metallic clankings from Bowman's pod, now almost half a mile below the surface of Jupiter V. From the lip of the shaft where his own tiny private spacecraft was balanced as far over the brink as he dared risk it, Kimball could see the other pod only as a little group of red and white identification lights. He waited, with mounting excitement and impatience, as Bowman took his time with the telescope.
Then, coming from far below via the speaker of the radio link, came three simple words that chilled him to the bone.
"Oh my God . . ." said David Bowman, very quietly in a tone that conveyed no fear or alarm-only utter, incredulous, surprise.
"What is it?!"
He heard Bowman draw a deep breath, then answer in a voice that he would not have recognized, yet was completely under control.
"You won't believe this, Jack. That light down there-I wasn't mistaken. I've got the telescope on it-the image is perfectly dear. I can see the bottom end of the shaft. And it's full of stars."
THE IMPOSSIBLE STARS
"Say it again, Dave," said Kimball. "I didn't hear you clearly."
"I said it's full of stars."
"Do I read you correctly-stars?"
"Yes-thousands of them. It's like looking at the Milky Way."
"Listen, Dave-I'm going to haul you up and have a look myself-okay?"
To Kimball's surprise, Bowman agreed at once to this change of plan. Usually it was very difficult to divert the skipper from any procedure he ha
d decided upon: he was fond of quoting Napoleon's "Order plus counterorder equals disorder." But now, he seemed not only willing but anxious to change places.
The line came up effortlessly; Bowman was obviously using the jets to help. When the pod floated up over the edge of the slot, Kimball peered into the bay-window, and was relieved to see his friend smile back, though in a slightly dazed manner.
"Sure you're okay?" he asked.
Bowman nodded.
"Sure," he said. "Go down and look yourself."