Jupiter (40 page)

'Maintain this distance from them,' Krebs repeated. 'Conform to their course and speed.'

Grant had never felt so small, so dwarfed. From a distance of fifty-some kilometers the Jovians reminded him of a stately herd of elephants, but they were so blessedly
big
. Bigger than any creature that had ever lived on Earth. Bigger than a city. We're just puny little insects, compared to them. Ants. Microbes.

'They're following the flow of organics,' O'Hara said.

'Cruising in the current,' Karlstad agreed.

'I can see that,' snapped Krebs. 'Stop this chattering! Check all systems. Now.'

Grant felt resentful as he disengaged from the sensor data. Why can't we all watch them? he grumbled to himself. We don't need to check the damned systems. If there's something wrong we'll know it right away.

He realized that his headache was still pulsing away; he had ignored it during the excitement of seeing the Jovians. But the pain in his back was nagging at him, too, no longer merely stiffness but an ache that he couldn't quite pin down, like an itch that moved when you tried to scratch it.

Then he saw it in razor-sharp clarity. The number two thruster was sputtering, its plasma flow no longer smoothly laminar. The hot ionized gas was crinkling, twisting in the thruster tube. The magnetic fields that should be guiding and accelerating the plasma were pulsating fitfully.

Grant felt the thruster's imminent failure as an increasingly sharp pain. His first instinct was to shut down the thruster and allow the automated repair program time to reline the tube with heat-shielding ceramic spray and replenish the liquid nitrogen coolant for the magnets.

To do that, though, he needed the captain's approval. The thruster could not be shut down unless Krebs physically relinquished her control of the propulsion system.

'Captain, thruster number two—'

'I see it,' Krebs said.

'We should take it off-line for repair,' Grant told her.

'Not now.'

'But it's headed for catastrophic failure.'

'Not for another twenty hours.'

Grant saw the diagnostic and double-checked it with a glance at his console screens. 'But Captain, that's only an estimate. It could fail much sooner.'

Her voice heavy with disdain, Krebs said, 'If we shut down the thruster we will slow down. The beasts out there will move away from us. We must keep pace with them.'

'Even if we lose the thruster altogether and can't get ourselves out of the ocean?' Grant demanded.

'We are here to get data. We can always fire off a data capsule.'

'But we'll die!'

'The data comes first. That is what is important.'

She doesn't care if we live or die, Grant said to himself. Our lives, even her own life, isn't as important to her as observing these creatures.

'The thruster can be repaired without taking it off-line,' Krebs said calmly.

Grant checked into the maintenance program and found that she was right, up to a point. 'It would only be a temporary patch," he said. 'The program recommends complete shutdown for necessary repairs.'

'Do what you can, Mr Archer,' Krebs said. 'The rest of us have observations to make.'

Fuming at the idea that he was forced to do a grease-monkey's work while the others were acting as scientists, Grant rechecked the maintenance program, then activated the automated sequence that started the repair work without shutting down the thruster.

The problem was a vicious circle, a closed negative feedback loop. The ceramic lining that shielded the thruster tube from the star-hot plasma flowing through it had eroded away in spots, allowing too much heat to soak through the metal walls of the tube and boil away some of the liquid nitrogen that kept the thruster's superconducting magnet properly cooled. The magnetic field was wavering, kinking in spots, which became hotter than normal, thereby eroding away more of the ceramic heat-shield material.

Grant saw the problem as a visual image against his closed eyelids, felt it as a twitching pain that was spreading across his back. I've got to get the magnetic coil cooled down properly, he knew. If it heats up past its critical temperature, the whole magnetic field will collapse and release enough energy to explode like a bomb.

But pumping more liquid nitrogen to the magnetic coils was like sticking a finger in a dike that was crumbling. Nothing more than a stopgap. I've got to resurface the tube with ceramic. But how can I do that while the plasma's still flowing through the goddamned tube?

The maintenance program showed him how. He saw the recommended emergency procedure: pump the liquified ceramic into the plasma stream while alternating the magnetic field so that it made the electrically-conducting plasma swirl in a helical motion as it moved down the tube. The ceramic will be forced to the outer edge of the swirling helix, plastered against the wall of the tube. Some of the ceramic will stick to the wall and begin to solidify.

Fine, Grant thought as the images flashed through his brain. But most of the ceramic will flow right down the tube and out the thruster nozzle.

It's a brute-force fix, he realized, but the only one that could be done as long as Krebs refused to shut down the thruster for proper repairs.

Swallowing hard, Grant spoke the sequence of alpha-numerics that triggered the repair system. He watched the ceramic being injected into the plasma as the magnets began pulsing according to the preset program. His back throbbed and twitched, his head felt slightly giddy. This isn't going to work, he told himself. All I'm doing is pumping the ceramic out of the ship.

But slowly the temperature along the thruster tube wall began to creep down. A single sharp
ping
rang in his ears and the program automatically increased the flow of liquid nitrogen to the superconducting coils. Grant saw the magnetic field stabilize, the plasma's swirling smoothed to a clean laminar flow.

It's done, he saw. The heat transfer across the tube wall is back to within tolerable levels. The pain in his back had eased away.

But it was only temporary, Grant realized. A stopgap repair, a Band-aid on a gushing wound. The problem would recur. Checking the system reserves, Grant saw that he had used more than half of the available ceramic. If— no,
when
the thruster got into trouble again it would take all the ceramic that was left to fix it. If that would be enough.

'Karlstad, prepare a data capsule,' Krebs ordered. 'I want everything we have recorded to go into it. Every bit of data.'

'Captain, that's the communications specialist's job,' Karlstad replied.

'You do it,' Krebs snapped. 'Dr O'Hara must devote her full attention to piloting.'

Zheng He
was still cruising some fifty kilometers from the herd of Jovians. The creatures were still grazing placidly along the stream of organic particles. Grant was still worried about the plasma thruster. It was performing well enough, but the thrusters were running at almost full capacity as the ship struggled to keep pace with the Jovians.

They're gliding along easily, Grant thought, almost lolling in the water. Even so they're going so fast that we're barely able to stay with them. What do we do if they get frightened and run away?

But the idea of anything frightening such massive beasts almost made Grant laugh. What could possibly bother them? They are the lords of this creation, stately and immense, unperturbed in their power.

He had lost track of time. They had all been on the bridge continuously since they'd first detected the Jovians, taking only quick breaks to plug in a squirt of food when the life support program called out their scheduled meal times.

The lights that the Jovians flashed back and forth among themselves fascinated Grant. What can it mean? Are they signaling to one another? Could it be a language of some sort, a visual language? Or is it just some kind of display, like a peacock showing off his feathers?

'They don't seem to be using sound for communications,' Muzorawa reported aloud. 'Our audiophones are not picking up anything except the slight turbulence caused by their rowing motions.'

'They swim stealthily,' Krebs observed.

'Yes,' Muzorawa agreed, nodding. 'They hardly make a sound.'

'That could be to keep them from being noticed by predators,' Karlstad said.

'Who would even think of preying on some great huge creature like them?' O'Hara asked.

Karlstad snickered. 'You've got predators in your bloodstream right now, Lane. We're millions of times bigger than bacteria.'

'Less talk, Dr Karlstad,' Krebs grumbled. 'Get that data capsule prepared.'

'It's almost ready, Captain,' said Karlstad, tapping at his console's touchscreens.

Grant asked, 'Could they be talking to each other at sound frequencies that the phones don't pick up?'

'They go down to ultralow frequency,' Muzorawa answered, 'less than ten cycles per second.'

'What's the upper limit?' asked Karlstad.

'Nearly a hundred kiloHertz, far beyond the range of human hearing.'

'We should have brought a dog aboard,' Karlstad muttered.

'Or a few of the dolphins,' said O'Hara.

'Sound waves of that intensity,' said Krebs, 'can destroy living tissue.'

'Or crack this submersible like an eggshell, if they have enough power behind them,' Muzorawa said.

'Happy thought,' Karlstad groused.

'My point is,' Krebs said,'that those creatures would not use such a high frequency to communicate. It would hurt them.'

'But they might use it as a weapon,' Karlstad said.

'If they're communicating with each other,' Muzorawa said slowly, 'I would think it would be visually.'

'They light up like signboards, don't they,' O'Hara said.

'Like those airships that hovered over football matches when I was a child,' Karlstad agreed.

The lights flickered on and off so quickly that Grant couldn't tell if they were forming patterns of any sort. They were almost as fast as strobe lights.

'Where is my data capsule?' Krebs demanded.

'I was just about to tell you, Captain. The capsule is ready for your input.'

Scowling, Krebs pushed off the overhead and settled next to Karlstad like a bulky log sinking down beside a willowy undersea reed. Karlstad tapped one of his touchscreens and the yellow communications light winked on.

'Data capsule number two,' she said, her harsh voice flat, emotionless. 'We have encountered a group of very large organisms. They appear to be ingesting the organic particles that drift through the sea. We are following them and will continue to do so until our life support supplies go critical.' Krebs touched the screen and the light went off. 'Is that all you'll be saying?' O'Hara blurted out. 'Won't you tell them about their signaling lights?'

'They'll be able to see the lights as well as we do,' Krebs said. 'They can draw their own conclusions as to whether they are signals or not.'

'But they've got to be!' O'Hara said. 'What else could they be?'

'Launch the capsule,' Krebs said to Karlstad. Giving O'Hara a sour look, she retorted, 'They could be almost anything, anything at all. Don't leap to conclusions.'

Karlstad launched the capsule with the touch of a fingertip against a screen. Grant felt it as a slight shudder.

'The lights flicker on and off so fast,' Muzorawa said,'that it's impossible to tell what they are.'

'Can't we slow them down?' Grant asked. 'I mean, run our imagery of them at a reduced speed.'

'Slow motion?'

'Yes.'

Muzorawa thought it over for a moment, then said, 'Yes, that's a good idea. Captain?'

'Do it,' Krebs snapped.

It took several minutes for Muzorawa to program the imagery stored in the sensors' computer memory. Finally he told them he was ready.

'Put it on the main screen,' Krebs ordered.

The ache in Grant's back was returning. He could not see anything wrong in the display screens of his console, but the ache •warned him that the thruster was starting to decay again.

Looking up, he saw on the wallscreen what appeared to be a still picture of one of the Jovians. No, its flippers were moving, but so slowly that Grant could see little silvery particles in the water tumbling in the wake of those powerful paddles of flesh. Diamonds, he realized anew. They're swimming through a cloud of diamonds — and food.

Though the beasts were still some fifty kilometers distant, the cameras' magnification showed them in some detail: their skins looked gray, rubbery, but mottled with rough lumps and knobs and - eyes. Those things had to be eyes; rows of them, hundreds of them staring out into the hot, dark sea. Grant shuddered. For a moment he felt as if those eyes were looking at him, watching him, appraising the intruding aliens from another world.

They're so huge, Grant thought. How could any creature grow to such enormous size? How does its nervous system control those flippers? Where is the brain located? Lord, one of those flippers could crush us with just a flick.

He saw patches of different colors here and there on the skin of the beasts. Parasites? There's a whole biosphere in this ocean, with plenty of ecological niches for all sorts of creatures. The organics from the clouds are at the bottom of the food chain and these gigantic super-whales must be at the top. What else are we going to find?

Red and orange lights glowed along the huge flanks of the massive creatures, strange puzzling designs that lit the ocean with their eerie glow. They made no sense to Grant, they gave no hint of meaning.

'Well, at least they're not saying "Earthlings go home,"' Karlstad wisecracked.

'But look,' Muzorawa pointed toward the wallscreen,'they are all repeating the same set of symbols.' 'Is it writing?' O'Hara asked. 'Impossible,' spat Krebs. 'And yet…'

'It must mean
something
,' Karlstad said.

'It means something to them, I should think,' Muzorawa murmured.

Krebs started to say, 'Do not leap to—' She stopped, open-mouthed. Grant saw it, too. So did all the others.

One of the Jovians displayed an image of a round, saucer-shaped object, with a single row of lights dotting its forward side. The saucer was in deep red, the lights a bright orange. Almost immediately, the others began to show the same picture.