Just now father and son were walking into Professor Bell's little laboratory.David asked his father, "Sir, we've been in the Station three weeks, and you've never been in the lab?"

"No, I haven't." Commander Rhodes snorted. "In the navy we don't waste time with this sort of thing." Another snort. "But you wouldn't understand."

His son shrugged. The old argument. Less than a month ago in routine deepsleep they had journeyed together out to this G.o.dforsaken ice ball, and on arrival they had promptly gone their separate ways: the commander to take charge of the seismic research program, the student to intern with Professor Martin Bell.

The affinity between Bell and his son puzzled the officer. Bell's military and/or naval background was worse than barren. In their mercifully brief conversations the commander had learned that the savant thought a warrant officer was a sort of process server, that Wellington was a type of boot, that Salamis was an Italian food.

The senior Rhodes looked around suspiciously. "Where's the professor?"

"Out. He knows you don't like him. Shall we start with his new s.p.a.ce suit?"

Commander Rhodes sniffed. "Make it fast. I launch at eleven hundred."

"Well, as I'm sure you know, the gravity on Jupiter is more than two and a half times Earth gravity."

"Of course."

"And Jupiter doesn't really have a surface. It's all gas, a mixture of hydrogen and helium, for hundreds of kilometers, until you hit liquid hydrogen. If you drop a probe on the planet, it will send back data for a few hours, then it sinks, disappears forever. That's what happened to the Galileo probes, and all that came after."

"I know all that, boy. Get to the magnetic stuff."

"Yes, sir. Well, the International s.p.a.ce Agency would like to be able to turn a man loose in that upper atmosphere, but they can't. Gravity would pull him into the center, where the temperature is 40,000 Kelvin and pressure is a hundred million times Earth's surface pressure.

The standard backpack retro suit doesn't work-the magnetic field fouls the instruments. The man can't tell whether he's moving up or down or sideways. He soon spins out of control."

"True, true," murmured the officer.

"So what we need, sir, is a system that deals with both magnetism and gravity, something that lets the astronaut move safely and at will in the outer reaches of the atmosphere."

"So Bell's still harping on that," muttered the commander. "Kind of sad, when you think about it. I'm told he was once a very famous scientist."

His son hesitated a moment, then continued. "Here's how it works. Jupiter's magnetic field is generated by a rotating sh.e.l.l or core of liquid metallic hydrogen. This magnetosphere is really tremendous, many times Earth's. It extends fifteen million kilometers from the planet and envelops most of the satellites. It bubbles and boils-causes all kind of problems to the circuits of s.p.a.cecraft. Prospero has to use special wavelengths. Our Station is bis.m.u.th-shielded, of course. Jupiter's poles are reversed, compared to Earth's but that's irrelevant for the professor's antigrav? ity process. The important thing is, Jupiter's north magnetic pole repels all other north magnetic poles, however created."

"Mm," murmured the officer. He looked at his watch.

The youth began to speak faster. "For travel in Jupiter's northern magnetic field theprofessor creates a north magnetic pole in his s.p.a.ce suit. For vertical movement within the planetary atmosphere, he varies the strength of the created field. Adjustments for horizontal movement are also available. The pulses are transmitted automatically and directly to a standard backpack of retro-thrusters. Response to turbulence is automatic and instantaneous.

The traveler can move in a straight line, any direction, by simple willpower."

"Willpower? Now wait a minute." The commander was trying to recall things he had heard about Bell and his notorious theories. "This . . . field. How does he create it?"

"Okay, the first thing he tried was a simple battery-powered circuit. It worked for half an hour, then the tremendous planetary magnetic field simply wiped it out. The problem was finding proper insulation. He faced a dilemma. On the one hand he had to provide a certain amount of shielding from Jupiter's field, but on the other he had to release his own little field.

He tried all the standard shielding metals. No good. If they shut out Jupiter, they killed his own field as well. Then he tried the nonmetals, such as tar, plastic, asbestos, even sulfur. They seemed to work a little better. A sh.e.l.l of mineral calcium phosphate gave him an operating life of nearly two hours. Well, the next step was obvious. He tried living calcium phosphate: the human skull. It was the-per?

feet insulator. It worked. It let enough of Jupiter's field in, enough of ours out."

"You're talking cranial implants?"

"Oh, no, sir. He uses no metals, no silicon circuitry. Nevertheless he does generate a field, a very sophisticated field, and it's instantly and precisely tunable by the operator. He uses natural brain waves-alpha, beta, theta. They are all sources of electromagnetic radiation, and every one of them creates its own little magnetic field. Under proper mental control, they provide the exact magnetic field needed to conform the astronaut to Jovian magnetism, so he can move three-dimensionally at will in the atmosphere. And the astronaut's hands are free."

He pointed to a baggy suit draped on a form by the wall. "And there it is. I loaded the retros this morning. It's ready to go." His voice vibrated with pride.

"It will never work," the commander said grimly. "It's a killer. I'll certainly never permit the professor or anyone else to test it on the planet. Including you." He put his hands on his hips and faced his son. "The professor and his s.p.a.ce suit must leave on the next packet." The words were clipped, harsh, precise. "David, you will stay, and you will register as a midshipman candidate. This is, after all, a naval outpost."

"Dad! Father!"

An overhead speaker interrupted. "Commander Rhodes, Pros? pero is ready and waiting." It was the strained voice of Lieutenant Katlin.

Noon Log They were gathered in the communications room for the noon log entry, with Lieutenant Commander Schaum at the head of the table.

Schaum smiled at the a.s.sembly. "Looks like everybody's here." His voice slowed, took on an official timbre. "We're in the comroom of Station Ganymede, on Jupiter's third moon. Time, twelve noon, July 27. Attending, myself, Eric Schaum, Lieutenant Commander, Dr. Martin Bell, consultant; Lieutenant Gunther Katlin; Dr. Derek Melchior, of 'Bourse'magazine; and Mr. David Rhodes, midshipman candidate."

He paused, glanced at the readings on the weather mainframe near his elbow. "Deborah's 'Go' is of record. Mission Seismos is underway, and we will follow the action on the globe."

He looked toward a side table, over which hovered a large illuminated holographic globe some two meters in diameter. Rank and file referred to it variously: Fatso . . . Peewee . . . Ole Devil . . . much depend? ing on mood and speaker. Schaum liked none of these but couldn't do much about it. The same names were used in casual reference to the globe's eponymic planet.

With his laser the lieutenant commander pointed to two tiny lights, one green, and under that a red, that blinked intermittently on the globe's slowly rotating surface. "As we see, Prospero, commanded by Lieutenant Gordon Leclerc, is presently in equatorial orbit over Jupiter and has lowered the probe Ariel by cable into a light-colored high-pressure cloud-zone that we call Epsilon South. It girdles the planet just below the equator.

"Ariel is commanded by Station Chief Commander Marshall Rhodes with a crew of two, Petty Officers Stimson and Hoyt. Ariel has no motive power of its own. From half a mile above, Prospero is pulling it along through the zone by cable, and adjusts...o...b..tal speed to match Epsilon's eastward flow, so that the probe encounters little or no motion relative to the belt, and no strain is placed on the cable other than the weight of the probe. Prospero hovers overhead at all times, and the cable continues to link the two vessels for purposes of motion and communication.

"In this first hour Ariel is scheduled to drop four seismic charges and to record the resultant echoes. As I speak, she has already dropped two, and within minutes will drop a third. In the second hour-" he glanced up at the wall clock, "-beginning about ten minutes from now, Ariel will move into the adjacent band, known as the South Equatorial Belt, or Zeta, where the program will be repeated. These soundings are being sent up to Prospero, then forwarded here, and from here they go to the Seismology Lab in California. With these and similar records we expect to learn a great deal about Jupiter's core. At the end of the second hour Prospero will retrieve the pod and return to base here on Ganymede."

Dr. Melchior held up a hand. "Uh, Commander, about these seismic bombs. Is this the same as prospecting for oil, back on Earth?"

"Not exactly, sir. Perhaps a word of explanation . . ."

"Please."

"If Dr. Bell would oblige," said Schaum.

The professor shrugged. "The object, of course, is to locate a discontinuity on the core surface. This discontinuity may or may rot represent an anticlinal upheaval, which may or may not be rich in heavy metals. But it all starts with finding the discontinuity. So we send forth our specially designed self-propelled seismic bomb. It's loaded with liquid oxygen, and it sucks in hydrogen from the surrounding atmosphere, and it burns and makes super-hot steam and that steam drives the bomblet. If we're lucky, it pa.s.ses through the gas atmosphere, which is at least fifteen hundred kilometers thick, and then it enters the next layer, liquid hydrogen, ten thousand kilometers deep, and hot, 700 Kelvin, but not hot enough to affect the bomb. Finally, it's through this layer and into the next one-a real oddity, more liquid hydrogen, but it's a metallic liquid.""Like mercury?" Dr. Melchior said.

"Sort of. And now things get serious. This layer is hot-eleven thousand Kelvin-twice the temperature of the surface of the Sun. So now our little blaster is put to the ultimate test. This last sh.e.l.l is 50,000 kilometers thick. Fortunately, our little fellow doesn't have to go through it."

"So what happens?"

"Our bomb lasts about fifty milliseconds in this last sh.e.l.l. But that's fine. That's the way we want it. On entry, it blows. The explosion creates the waves we need, good strong longitudinals. They travel at a fantastic rate in all directions, including down to the surface of the core. Even so, because of the distance, they may take several hours to strike and reflect back. Some of the reflections may bounce back quicker than others. When that happens, it indicates a discontinuity. Magnetic tapes in Ariel pick up the reflections, forward them to Prospero, and so on. Does the pattern show metal? In California the experts a.n.a.lyze the feedback. They say, the higher you go in the Periodic Table, the stronger the returning reflections. That's the way it works on Earth. But here? n.o.body knows for sure. With this program we hope to find out."

"Very informative, Professor," Melchior said. He turned to Schaum. "And, Commander, I gather this is not the first trip?"

"That's true. As a matter of fact, Ariel has already made three unmanned missions with substantially the same seismological program, and in these prior missions explosives were dropped. However, results were not completely satisfactory, owing to some confusion in aligning coordinates, and Commander Rhodes felt that if he personally guided the pod, it could do a much more precise job."

The officer pressed a key on his terminal and a second hologram appeared beside the big globe. "At this point I interpolate a visual into the record. We are looking through Prospero's belly camera down the cable, a stretch of about 750 meters, where it disappears into Zeta. The cable is hardened polymer, two inches thick, four times stronger than steel, and tested to endure tensions far greater than any that Ariel is expected to encounter on the mission. We pause now while Prospero pulls the ship over into Zeta's cloud belt." The two little lights moved slowly a few centimeters. During this movement Schaum stole a look at the dials on Deborah's instrument face, then looked over at the consultant. Bell, who had also been studying the instruments, looked up at Schaum and mouthed one word in silence. "Abort."

Schaum hesitated, then frowned and shook his head. He said quietly, "Off the record. I see it, Martin. Weather picking up. But we had a 'Go.' "

Deborah knew only two words: Go . . . Nogo.

It had not always been that way. The weather computer- named for the very wise Biblical prophetess-had been originally programmed to report her predictions in detailed a.n.a.lyses. "In- zone, between 40 and 45 degrees west longitude and between 1400 and 1700 UT, winds 30% higher than normal lessening to normal shortly before 1745." And then there would be an officers' conference, sometime short, sometimes prolonged. Did Debbie mean it was safe to launch the probe?

When Marshall Rhodes a.s.sumed command of the station, he solved the problem. He ordered Lieutenant Commander Schaum to reprogram Deborah. Henceforth the prophetess would say either "Go" or "Nogo." All future launches would abide by her announcements.Schaum's protests availed him nothing.

The new system seemed to prove the chief right. Three unmanned probes were launched on "Go" and all went forth and returned safely. "You see," Commander Rhodes told the staff while eyeing Schaum sternly, "no more gobbledygook."

And now Schaum envisioned the ships in his mind. Ariel resembled a miniature blimp, but with important differences. The cabin under the bag was gas-tight; the bag itself was polymer, super tough, yet flexible at temperatures as low as minus 175 decrees Centigrade. It worked like a terrestrial hot-air balloon: the bag was filled with heated Jovian atmosphere, in whose upper reaches it now floated, dangling from its mother ship.

So now ISA wanted to make comprehensive studies of the planet's distant enigmatic core.

Seismic exploration might well clear up the mystery. But the agency had run out of money and it had called on the Interplanetary Congress for help, and Congress had done the only logical thing. Before they launched a billion-dollar project, they asked for a Preliminary Report.

Hence Prospero and Ariel.

Professor Bell had already been at work in Ganymede Station for several months when Lieutenant Commander Schaum arrived. Schaum had known the scientist by reputation, but before coming here had never met him personally.

But this was here and now, and at this very instant the old man was pressuring him. Abort .

. . abort . . . and Schaum knew that powerful forces were looking over his shoulder-the chief; Congress; ISA. Abort-and end any chance for the appropriation? What would the chief say?

Would he, Schaum, be able to face Rhodes? Leclerc? Of course the mission was dangerous. A given. Nothing new about that. True, the weather was worsening. Bad, but not a calamitous increase in the risk level. No reason to quit in mid-trial. Not yet, anyway.

He looked at Bell, and he couldn't help frowning again. He well recalled the celebrated Symposium of the Naval Research Society in Paris not so long ago, where Bell had presented his theory of motion control on Jupiter via human brain waves. Schaum had been there and had listened to the jeers. One famous scientist, recipient of two n.o.bels, had enumerated six laws of physics that Bell's theory violated.

He called out, "Hold on! Something coming in! It's Ariel!" They all leaned forward and listened to the calm voice of Commander Rhodes.

"Mr. Leclerc, we will abort. . . ."

Inside Ariel The weather on the giant planet was stormy, always, everywhere Especially in the interbands. A given. The crew in Ariel didn't like it, but they were pros. They had been trained for this and they tried to adjust. But this weather was different. It had sprung up out of nowhere, and it was developing into something beyond anything that could be called a mere storm. Commander Rhodes was no coward, and he knew that aborting now would be costly, both for his career and for the future of Jovian research. But this was too much. Petty Officers Hoyt and Stimson had already strapped in. As he headed for his seat, the commander got his voice under rigid control and called the mother ship, far overhead. "Mr. Leclerc, we will abort. Bring us up, if you please." Despite the languid monotone and the scratchy reception, Lieutenant Leclerc caught something in the words that tightened his throat and made him stammer, "Yes, sir, fast."Back at the Station the listeners around the table seemed to sag with relief. Bell continued to monitor Deborah's dials. "That's a very unusual storm. Nothing like that in the records, and we go back at least a hundred years. Looks like the big one. Rhodes is smart to pull out."

Schaum wet his lips. Right, he thought. And now the next question: will they make it in time? The screen gave the Station audience a view not accessible to Ariel and perhaps not to Prospero. The Big One . . . ? They had talked about it. Not to worry, Rhodes had said. It wouldn't catch them. They were too smart. "It's probably moot," he said casually. "But I think I'll call Leclerc, get a condition report." He opened the line to Prospero.

Under other circ.u.mstances Lieutenant Katlin's bloodless face might have aroused serious concern. But just now n.o.body paid the slightest attention to him. He was thinking hard. This is a very bad storm. Deborah hadn't predicted it. The K-3 will blow, and they'll think the storm snapped the cable. Melchior gets what he wanted. I'll be in the clear. Totally.

G.o.d is looking after me. Ah, thank you, G.o.d. He stole a look at Melchior. The entrepreneur flashed him a friendly grin.

The howls of the tempest drowned out nearly all outside sounds in Ariel's little cabin. But not everything. There was a sudden "pop" from overhead. The three men looked up, listened intently. The little ship began to pitch and wobble. It rolled on its side. "The cable!" cried Hoyt. The two crewmen were already strapped in and endured the crazy motion better than Commander Rhodes, who grabbed at hand bars and worked his way back to his seat, where he eventually got himself strapped in.

Their umbilical cord to the mother ship was gone. No communication. No mobility. Just careening crazily along in winds of unimaginable fury.

The two horrified ratings looked wide-eyed at Rhodes. Stimson tried to call out, but the cataclysm outside ate his words. Hoyt was white-faced, paralyzed. Commander Rhodes knew exactly how they felt. He closed his eyes briefly, took a little comfort in the fact that his insurance was paid up, David could go on to graduate school, and that Muriel, his wife of twenty-five years, could probably remarry, have a good life. s.h.i.t.

Professor Bell pointed to the screen. He said somberly, "There goes your line, Mr.

Schaum." The cable was still visible, but it was contorting in loops. At one point it coiled upward, fully out of the clouds, and they could see the oddly shattered end, attached to nothing.

All communication between Ariel and Prospero was gone.

The Castaways The little ship continued to whirl and tumble. Not rhythmically, but spasmodically, in unpredictable twists and jerks. Inside, the three men grunted and gasped within their straps.

Hoyt's nose was bleeding. The commander smelled the acrid odor of vomit. And another odor, a stench, and no stranger in this business- fear.

Things were bouncing around in the cabin, sometimes on the floor, sometimes the ceiling was the floor. There was an illusion of ozone. Marshall Rhodes could see distant lightningstrikes through the cabin window. He shouted above the din, "They'll find us ... they'll drop another line!" And immediately he realized the futility of the statement. Even if the mother ship could find them, there was no way to reattach the cable. Th lock socket was surely destroyed. With the eyelet gone, the cable could not be fastened to the little ship.

Stimson gave him a puzzled look, tried to shrug, couldn't.

A realist, thought the commander. What now? Prospero would probably soon have grapples out and would be searching diligently. And probably fruitlessly. For if and when Prospero found the errant Ariel, then what? As of the moment he could not imagine any effective rescue mechanism. On the other hand, maybe Leclerc could figure out something. But not much time to do it. If the mother ship didn't find Ariel in the next five minutes, it probably never would. In a mere sixty seconds, orbiter and target might find themselves a hundred miles apart, in any direction, with the gap rapidly widening. Because of the planet's t.i.tanic magnetic field, radar was useless. For practical search purposes Ariel was invisible.

Rhodes choked back a moan. Oxygen for twenty-four hours, he thought. Fortunately no need to power down. Everything operated from the nuclear unit. With care, and if n.o.body goes bonkers, maybe we can stretch it out to thirty-six. And then what? He refused to think about it.

What had gone wrong? The superstorm, of course. The Big One. Still, the cable should have held. First serious miscalculation he had made in a very promising career. And very likely the last. Deborah had said, "Go," and he had launched. He couldn't blame Schaum. No, only himself. He had been so determined to do it right, make sure of that appropriation. That's why he had taken the mission himself.

Chaos and time shrieked on.

Dr. Bell hurried around and leaned over the intercom. Schaum looked up, then moved aside a little, too surprised to protest.

The scientist spoke crisply. "Station calling Prospero. Leclerc? Bell here. Ariel is by now into Zeta. She will go with the flow, two hundred miles an hour. Rhodes probably has several charges left. He may throw out one or two, set for immediate ignition. They should give a fair fix."

Schaum listened to this in amazement.

Bell continued with cold authority. "Stay overhead his estimated position. Meanwhile lower the cable an additional five hundred feet. Monitor tension on the cable. One jerk means pay out more cable. Three jerks means reel in. I will arrive at Ariel's estimated position in fifty minutes in the shuttle, which I will leave on automatic. Eventually somebody will have to pick it up. Do it, man! I return you now to the commandant. Out."

He turned away and hurried from the room.

Schaum was flabbergasted. Old Doc Bell . . . taking over? But as he collected his wits, he thought about it. Everything had sounded so right-exactly what he or Leclerc would have proposed if Bell hadn't said it first. But then he realized what the scientist was really intending.

No! This was insane. He chilled an impulse to leap up and run after the man. He didn't think he could catch him; furthermore, he didn't want to leave his post. He cried out, "No!"

then he looked around the table. "Stop him!" Dr. Melchior and Lieutenant Katlin seemedfrozen. Rhodes? Where was young Rhodes? Gone. Certainly after the professor. The youngster would bring him back. Schaum relaxed a little. But then he thought . . . better make sure.

He called the shuttle bay. "Pensol? Anybody there? Anybody? If you can hear me, listen up.

Dr. Bell will attempt to take the shuttle. Don't hurt him, but don't let him near it. h.e.l.lo? h.e.l.lo?

Pensol? d.a.m.n." Next, back to Prospero. "Lieutenant Leclerc? You hear that? Can't Ariel's own crew reattach the cable? They have suits, don't they?"

"Suits, yes, Commander, and retropaks, for that matter. If the cable comes down and rests on Ariel, or maybe a few yards away, where they can actually see it, maybe they can grapple it, bring it in, depending on the condition of the cable lock. We don't know what their situation is.

With the cable snapped, we can't communicate with them."

Schaum noted that an entry had just then appeared on the console registry. "EXIT SHUTTLE, 14:03." He went into momentary shock. Young Rhodes hadn't caught the professor.

He shuddered. "Well, there he goes."

He listened vaguely to Leclerc.

"1 got that, sir. Sorry. Permission to do as Bell says?"

"Yeah, go ahead." As good as anything, or nothing. He could predict the next steps. As soon as the shuttle arrived in the clouds of Zeta, the venerable madman would don his brand-new untried brain-controlled motor suit, and he would open the shuttle air lock, and he would jump out into the storm. Then what? Probably start falling, and he would fall and fall and fall, faster and faster and faster, h.e.l.l-bent on joining three ghosts. He would be incinerated long before he reached the monster planet's rocky core.