The Fountains of Paradise Part II

seven scientists were trapped in the solar system's highest tower, and morgan was determined to rescue them before their chamber became a tomb--the conclusion of the master's "final" sci-fi thriller

Synopsis: After retiring from a distinguished diplomatic career, Johan Rajasinghe fulfills a lifelong dream by settling in a villa in Taprobane, near Sri Kanda, the sacred mountain. He is visited by Vannevar Morgan, an engineer whose most impressive achievement is the ultimate bridge, an architectural and engineering triumph linking Europe and Africa. Morgan has come to this secluded part of the world with an even more ambitious concept--a tower that will support a space elevator that will make travel to the heavens cheaper and more accessible than ever. But the hitch is that the base of the tower must be situated on Sri Kanda, location of an ancient Buddhist monastery. The engineer has come to ask the monks for permission to build the tower.

Needless to say, the monks are reluctant to give up their holy spot in the name of space technology. After fruitless negotiations, Morgan descends Sri Kanda, only to find himself in the midst of a dense swarm of butterflies in migration. The taxi driver relates an old legend: The butterflies are the souls of the warriors of Kalidasa, the former ruler of Taprobane, who had lost his army at Yakkagala. Yearly, the butterflies head for the mountain and die at its lower slopes. Occasionally, they reach the halfway point, and the legend states that if they ever reach the sacred temple at the top, Kalidasa will have conquered and the monks will have to leave. Here ends Part I.

Years later, quite unexpectedly, the legend becomes reality: The butterflies are swept up the mountain and the monks must leave. Morgan and his engineers begin work on the tower, whose structure is based on a remarkably strong substance known as hyperfilament. At the beginning of Part II, the tower has been years in the making and a research team of scientists, headed by Professor Sessui, is stranded on the tower after an operations disaster.

Five Kilometers from the terminus, the red ALARM symbols flashed again. Driver-pilot Rupert Chang studied them with a frown of annoyance, then pressed the RESET button. They flickered once, then vanished.

The first time this had happened, 200 kilometers higher, there had been a hasty consultation with Midway Control. A quick check of all systems had revealed nothing amiss; indeed, if all the warnings were to be believed, the transporter's passengers were already dead. Everything had gone outside the limits of tolerance.

It was obviously a fault in the alarm circuits themselves, and Professor Sessui's explanation was accepted with general relief. The vehicle was no longer in the vacuum environment for which it had been designed; the magnetospheric turmoil it had now entered was triggering the sensitive detectors of the warning systems.

"Someone should have thought of that," Chang had grumbled. But with less than an hour to go, he was not really worried. He would make constant manual checks of all the critical parameters.

Battery condition was, perhaps, the item that concerned him most. The nearest charging point was 2000 kilometers higher up, and if they couldn't climb back to that, they would be in trouble. But Chang was quite happy on this score; during the braking process, the transporter's drive motors had been functioning as dynamos, and 90 percent of its gravitational energy had been pumped back into the batteries. Now that they were fully charged, the surplus thousands of kilowatts still being generated should be diverted into space through the big cooling fins at the rear.

Those fins, as Chang's colleagues had often pointed out to him, made his unique vehicle look rather like an old-time aerial bomb. By this time, at the very end of the braking process, they should have been glowing a dull red. Chang would have been very worried, indeed, had he known that they were still comfortably cool. For energy can never be destroyed; it has to go somewhere. And very often it goes to the wrong place.

When the Fire--Battery Compartment sign came on for the third time, Chang did not hesitate to reset it. A real fire, he knew, would have triggered the extinguishers; in fact, one of his biggest worries was that these might operate unnecessarily. There were several anomalies on the board now, especially in the battery-charging circuits. As soon as the journey was over and he'd powered down the transporter, Chang was going to climb into the motor room and give everything a good old-fashioned eyeball inspection.

As it happened, his nose alerted him first, when there was barely more than a kilometer to go. Even as he stared incredulously at the thin wisp of smoke oozing out of the control board, the coldly analytical part of his mind was saying, "What a lucky coincidence that it waited until the end of the trip!"

Then he remembered all the energy being produced during the final braking and had a pretty shrewd guess at the sequence of events. The protective circuits must have failed to operate and the batteries had been overcharging. One fail-safe after another had let them down; helped by the magnetospheric storm, the sheer perversity of inanimate things had struck again....

Chang punched the battery-compartment fire-extinguisher button; at least that worked, for he could hear the muffled roar of the nitrogen blasts on the other side of the bulkhead. Ten seconds later, he triggered the Vacuum Dump, which would sweep the gas out into space--with, hopefully, most of the heat it had picked up from the fire. That, too, operated correctly.

He dared not rely on the automatic braking sequence as the vehicle finally crawled into the terminus; fortunately, he had been well rehearsed and recognized all the visual signals, so that he was able to stop within a centimeter of the docking adapter. In frantic haste, the air locks were coupled and stores and equipment were hurled through the connecting tube....

And so was Professor Sessui, by the combined exertions of pilot, assistant engineer and steward, when he tried to go back for his precious instruments. The air-lock doors were slammed shut just seconds before the engine-compartment bulkhead finally gave way.

After that, the refugees could do nothing but wait in the basement's bleak 15-meter-square chamber, with considerably fewer amenities than a well-furnished prison cell, and hope that the fire would burn itself out. The basement would eventually be the lowest part of the tower, but now it was 17,350 kilometers below Midway station and only 600 kilometers from Earth. It was one of scores of emergency refuges at intervals along the tower.

It was well for the passengers' peace of mind that only Chang and his engineer appreciated one vital statistic: The fully charged batteries contained the energy of a large chemical bomb, now ticking away on the outside of the tower.

Ten minutes after their hasty arrival, the bomb went off. There was a muffled explosion, which caused only slight vibrations of the tower, followed by the sound of ripping and tearing metal. Although the breaking-up noises were not very impressive, they chilled the hearts of the listeners; their only means of transport was being destroyed, leaving them stranded 35,000 kilometers from safety.

There was another, more protracted explosion--then silence; the refugees guessed that the vehicle had fallen off the face of the tower. Still numbed, they started to survey their resources; and slowly, they began to realize that their miraculous escape might have been wholly in vain.

A Cave in the Sky

Deep inside the mountain, amid the display and communications equipment of the Earth Operations Center, Vannevar Morgan and his engineering staff stood around the tenth-scale hologram of the tower's lowest section. It was perfect in every detail, even to the four thin ribbons of the guiding tapes extending along each face. They vanished into thin air just above the floor, and it was hard to appreciate that, even on this diminished scale, they should continue downward for another 60 kilometers--completely through the crust of the Earth.

"Give us the cutaway," said Morgan, "and lift the basement up to eye level."

The tower lost its apparent solidity and became a luminous ghost--a long, thin-walled square box, empty except for the superconducting cables of the power supply. The very lowest section--the basement was, indeed, a good name for it, even if it was at more than 100 times the elevation of this mountain--had been sealed off to form a single chamber, 15 meters square.

"Access?" queried Morgan.

Two sections of the image started to glow more brightly. Clearly defined on the north and south faces, between the slots of the guidance tracks, were the outer doors of the duplicate air locks--as far apart as possible, according to the usual safety precautions for all space habitats.

"They went in through the south door, of course," explained the duty officer. "We don't know if it was damaged in the explosion."

Well, there were three other entrances, thought Morgan--and it was the lower pair that interested him. This had been one of those afterthoughts, incorporated at a late stage in the design. Indeed, the whole basement was an afterthought; at one time, it had been considered unnecessary to build a refuge here.

"Tilt the underside toward me," Morgan ordered.

The tower toppled, in a falling arc of light, and lay floating horizontally in mid-air with its lower end toward Morgan. Now he could see all the details of the 15-meter-square floor--or roof, if one looked at it from the point of view of its orbital builders.

Near the north and south edges, leading into the two independent air locks, were the hatches that allowed access from below. The only problem was to reach them--600 kilometers up in the sky.

"Life support?"

The air locks faded back into the structure; the visual emphasis moved to a small cabinet at the center of the chamber.

"That's the problem, doctor," the duty officer answered somberly. "There's only a pressure-maintenance system. No purifiers and, of course, no power. Now that they've lost the transporter, I don't see how they can survive the night. The temperature's already falling--down ten degrees since sunset."

Morgan felt as if the chill of space had entered his soul. Even if there were enough oxygen in the basement to last them for several days, that would be of no importance if they froze before dawn.

"I'd like to speak to Professor Sessui."

"We can't call him directly--the (continued on page 124) Fountains of paradise (continued from page 118) basement emergency phone only goes to Midway. No problem, though."

That turned out to be not completely true. When the connection was made, driver-pilot Chang came onto the line.

"I'm sorry," he said, "the professor is busy."

After a moment's incredulous silence, Morgan replied, pausing after each word and emphasizing his name: "Tell him that Dr. Vannevar Morgan wants to speak to him."

"I will, doctor--but it won't make the slightest difference. He's working on some equipment with his students. It was the only thing they were able to save--a spectrometer of some kind--they're aiming it through one of the observation windows...."

Morgan controlled himself with difficulty. He was about to retort, "Are they crazy?" when Chang anticipated him.

"You don't know the prof--I've spent the past week with him. He's--well, I guess you could say single-minded. It took three of us to stop him from going back into the cabin to get some more of his gear. And he's just told me that if we're all going to die anyway, he'll make damn sure that one piece of equipment is working properly."

Morgan could tell from Chang's voice that, for all his annoyance, he felt a considerable admiration for his distinguished and difficult passenger. And, indeed, the professor had logic on his side. It made good sense to salvage what he could, out of the years of effort that had gone into this ill-fated expedition.

"Very well," said Morgan at length, cooperating with the inevitable. "Since I can't get an appointment, I'd like your summary of the situation. So far, I've only had it secondhand."

"There's not much to say. We had such short notice that there was no time to save anything--except that damned spectrometer. We have the clothes we're wearing--and that's about it."

Listening to that voice from space, and looking at the transparent--yet apparently solid--hologram of the tower, Morgan had a most curious illusion. He could imagine that there were tiny, tenth-scale human beings moving around there in the lowest compartment; it was only necessary to reach in his hand and carry them out to safety.

"Next to the cold, the big problem is air. I don't know how long it will be before CO2 build-up knocks us out."

Chang's voice dropped several decibels and he began to speak in an almost conspiratorial tone, obviously to prevent being overheard.

"The prof and his students don't know this, but the south air lock was damaged in the explosion. There's a leak--a steady hiss round the gaskets. How serious it is, I can't tell."

The speaker's voice rose to normal level again: "Well, that's the situation. We'll be waiting to hear from you."

And just what the hell can we say, Morgan thought to himself, except "Goodbye"?

Morgan turned back to the well-orchestrated chaos of the operations room and tried to let his mind roam as freely as possible over every aspect of the problem.

Seven men and women were stranded in the sky, in a situation that was unique in the whole history of space technology.

There must be a way of getting them to safety, before they were poisoned by CO2 or the pressure dropped so low that the chamber became, in truth, a tomb like Mahomet's--suspended between heaven and Earth.

The Man for the Job

"We can do it," said Warren Kingsley with a broad smile. "Spider can reach the basement."

"You've been able to add enough extra battery power?"

"Yes, but it's a very close thing. It will have to be a two-stage affair, like the early rockets. As soon as the battery is exhausted, it must be jettisoned to get rid of the dead weight. That will be around four hundred kilometers; Spider's internal battery will take it the rest of the way."

"And how much pay load will that give?"

Kingsley's smile faded. "Marginal. With a suited pilot of average weight, about fifty kilos, with the best batteries we have."

"Only fifty! What use will that be?"

"It should be enough. A couple of those new thousand atmosphere tanks, each holding five kilos of oxygen. Molecular filter masks to keep out the CO2. A little water and compressed food. Some medical supplies. We can bring it all in under forty-five kilos."

"Phew! And you're sure that's sufficient?"

"Yes--it will tide them over until the transporter arrives from the 10K station. And if necessary, Spider can make a second trip."

Morgan felt that a great weight had been lifted from his shoulders. Plenty of things could still go wrong, but at last there was a ray of hope; the feeling of utter helplessness had been dispelled.

"When will all this be ready?" he asked.

"If there are no holdups, within two hours. Three at the most. It's all standard equipment, luckily. Spider's being checked out right now. There's only one matter still to be decided. Who will...."

Vannevar Morgan shook his head. "No, Warren," he answered slowly, in a calm, implacably determined voice that his friend had never heard before. "There's nothing more to decide. I'm fifteen kilos lighter than you are. In a marginal operation like this, that should settle the matter. So let's not waste any more precious time discussing it."

Only as they were leaving the operations room on the way back to the summit did Morgan automatically feel for the little pendant concealed beneath his shirt. CORA--a coronary alarm--had not bothered him for months, and not even Warren Kingsley knew of her existence. Was he gambling with other lives as well as his own, just to satisfy his own selfish pride?

It was too late now. Whatever his motives, Morgan was committed.

Spider

How the mountain had changed, thought Morgan, since he had first seen it! The summit had been entirely sheared away, leaving a perfectly level plateau; at its center was the giant "saucepan lid," sealing the shaft that would soon carry the traffic of many worlds. No one could have guessed that an ancient monastery had once stood there, focusing the hopes and fears of billions for at least 3000 years.

Every time he came to the mountain, he found it more difficult to breathe, and he looked forward to the flood of oxygen that would soon gush into his starved lungs. But CORA, to his surprised relief, had never issued even a preliminary admonition when he visited the summit.

Everything had been loaded aboard Spider, which had been jacked up so that the extra battery could be hung beneath it.

Morgan's Flexisuit had arrived from Gagarin only 30 minutes earlier, and for a while, he had seriously considered leaving without one. Spider Mark II was a very sophisticated vehicle; indeed, it was a tiny spaceship with its own life-support system. If all went well, Morgan should be able to mate it with the air lock on the bottom of the tower, designed years ago for this very purpose. But a suit not only would provide insurance in case of docking problems; it would give him enormously greater freedom of action.

Almost form-fitting, the Flexisuit bore (continued on page 178) Fountains of paradise (continued from page 124) very little resemblance to the clumsy armor of the early astronauts, and, even when pressurized, would scarcely restrict his movements.

Morgan climbed the short flight of steps, stood for a moment on the capsule's tiny metal porch, then cautiously backed inside. As he settled down and fastened the safety belt, he was agreeably surprised at the amount of room. The two oxygen cylinders had been stowed under the seat and the CO, masks were in a small box behind the ladder that led up to the overhead air lock. It seemed astonishing that such a small amount of equipment could mean the difference between life and death for so many people.

Morgan had taken one personal item--a memento of that first day long ago at Yakkagala, where in a sense all this had started. The spinnerette took up little room and weighed only a kilo. Over the years, it had become something like a talisman; it was still one of the most effective ways of demonstrating the properties of hyperfilament, and when he left it behind, he almost invariably found that he needed it. And on this, of all trips, it might well prove useful.

He plugged in the quick-release umbilical of his space suit and tested the air flow on both the internal and the external supply. Outside, the power cables were disconnected: Spider was on its own.

The curving door of the capsule--the upper half of it transparent plastic--thudded softly shut against its gaskets. Morgan pressed the Check-out button and Spider's vital statistics appeared on the screen one by one. All were green; there was no need to note the actual figures. If any of the values had been outside nominal, they would have flashed red twice a second.

The quiet, calm voice of the controller sounded in his ear. "All systems nominal. You have control."

"I have control. I'll wait until the next minute comes up."

It was hard to think of a greater contrast to an old-time rocket launch, with its elaborate countdown, its split-second timing, its sound and fury. Morgan merely waited until the last two digits on the clock became zeros, then switched on power at the lowest setting.

Smoothly--silently--the floodlit mountaintop fell away beneath him. Not even a balloon ascent could have been quieter. If he listened carefully, he could just hear the whirring of the twin motors as they drove the big friction drive wheels that gripped the tape, both above and below the capsule.

Rate of ascent, five meters a second, said the velocity indicator; in slow, regular steps, Morgan increased the power until it read 50--exactly 180 kilometers an hour. That gave maximum efficiency at Spider's present loading; when the auxiliary battery was dropped off, speed could be increased to almost 250 klicks.

"Say something, Van!" said Warren Kingsley's amused voice from the world below.

"Leave me alone," Morgan replied equably. "I intend to relax and enjoy the view for the next couple of hours. What's the latest from the tower?"

"Temperature's stabilized at twenty--Monsoon Control zaps them with a modest megawattage every ten minutes. But Professor Sessui is furious--complains that it upsets his instrument."

"What about the air?"

"Not so good. The pressure has definitely dropped and, of course, the CO2,'s building up. But they should be OK if you arrive on schedule. They're avoiding all unnecessary movement to conserve oxygen."

All except Professor Sessui, I'll bet, thought Morgan. It would be interesting to meet the man whose life he was trying to save. He had read several of the scientist's widely praised popular books and considered them florid and overblown. Morgan suspected that the man matched the style.

"And the status at 10K?"

"Another two hours before the transporter can leave; they're installing some special circuits to make quite sure that nothing catches fire on this trip. And they're coming down the north track, just in case the south one was damaged by the explosion. If all goes well, they'll arrive in--oh, twenty-one hours. Plenty of time, even if we don't send Spider up again with a second load."

Despite his only half-jesting remark to Kingsley, Morgan knew that it was far too early to start relaxing.

Soon he was 30 kilometers up in the sky, rising swiftly and silently through the tropical night. There was no moon, but the land beneath was revealed by the twinkling constellations of its towns and villages. When he looked at the stars above and the stars below, Morgan found it easy to imagine that he was far from any world, lost in the depths of space.

Fifty kilometers; he had reached what would, in normal times, have been the lowest level of the ionosphere. He did not, of course, expect to see anything; but he was wrong.

The first intimation was a faint crackling from the capsule speaker; then, out of the corner of his eye, he saw a flicker of light. It was immediately below him, glimpsed in the downward-viewing mirror just outside Spider's little bay window.

He twisted the mirror around as far as it would adjust, until it was aimed at a point a couple of meters below the capsule. For a moment, he stared with astonishment and more than a twinge of fear; then he called the mountain.

"I've got company," he said. "I think this is in Professor Sessui's department. There's a ball of light--oh, about twenty centimeters across--running along the tape just below me. It's keeping a constant distance and I hope it stays there. But I must say it's quite beautiful--a lovely bluish glow, flickering every few seconds. And I can hear it on the radio link."

It was a full minute before Kingsley answered in a reassuring tone of voice.

"Don't worry--it's only Saint Elmo's fire. We've had similar displays along the tape during thunderstorms. You won't feel anything--you're too well shielded."

"Oh--it's fading out--getting bigger and fainter--now it's gone--I suppose the air's too thin for it--I'm sorry to see it go----"

"That's only a curtain raiser, said Kingsley. "Look what's happening directly above you."

A rectangular section of the star field flashed by as Morgan tilted the mirror toward the zenith. At first he could see nothing unusual, so he switched off all the indicators on his control panel and waited in total darkness.

Slowly, his eyes adapted, and in the depths of the mirror, a faint red glow began to burn, and spread, and consume the stars. It grew brighter and brighter and flowed beyond the limits of the mirror; Morgan could see it directly, for it extended halfway down the sky. A cage of light, with flickering, moving bars, was descending upon the Earth. On one of its rare visits to the equator, the auroral veil had come marching down from the poles.

Beyond the Aurora

Morgan doubted if even Professor Sessui, 500 kilometers above, had so spectacular a view. The storm was developing rapidly; short-wave radio--still used for many nonessential services--would by now have been disrupted all over the world. Morgan was not sure if he heard or felt a faint rustling, like the whisper of falling sand or the crackle of dry twigs. Unlike the static of the fireball, it certainly did not come from the speaker system, because it was still there when he switched off the circuit.

Curtains of dark-red fire, edged with crimson, were being drawn across the sky, then shaken slowly back and forth, as if by an invisible hand. They were trembling with the gusts of the solar wind, the 2,520,000-kilometer-an-hour ionic gale blowing from sun to Earth-- and far beyond. Even above Mars, a feeble auroral ghost was flickering now; and sunward, the poisonous skies of Venus were ablaze.

Above the pleated curtains, long rays like the ribs of a half-opened fan were sweeping around the horizon; sometimes they shone straight into Morgan's eyes like the beams of a giant searchlight, leaving him dazzled for minutes. There was no need, any longer, to turn off the capsule illumination to prevent it from blinding him; the celestial fireworks outside were brilliant enough to read by.

One hundred seventy kilometers; Spider was still climbing silently, effortlessly. It was hard to believe that he had left Earth exactly an hour ago. Hard, indeed, to believe that Earth still existed; for he was rising between the walls of a canyon of fire.

And now, like an airplane breaking through a ceiling of low-lying clouds, Spider was climbing above the display. Morgan was emerging from a fiery mist, twisting and turning beneath him. Many years ago, he had been aboard a tourist liner cruising through the tropical night, and he remembered how he had joined the other passengers on the stern, entranced by the beauty and wonder of the bioluminescent wake.

He had almost forgotten his mission and it was a distinct shock when he was recalled to duty.

"How's power holding up?" Kingsley asked. "You've only another twenty minutes on that battery."

Morgan glanced at his instrument panel. "It's dropped to ninety-five percent-- but my rate of climb has increased by sixteen percent. I'm doing two hundred and ten klicks."

"That's about right. Spider's feeling the lower gravity--it's already down by ten percent at your altitude."

That was not enough to be noticeable, particularly if one was strapped into a seat and wearing several kilos of space suit. Yet Morgan felt positively buoyant and he wondered if he were getting too much oxygen.

No, the flow rate was normal. It must be the sheer exhilaration produced by that marvelous spectacle beneath him-- though it was diminishing now, drawing back to north and south, as if retreating to its polar strongholds.

The stars were coming back into their own, no longer challenged by the eerie intruder from the poles. Morgan began to search the zenith, not with any high expectations, wondering if the tower were yet in sight. But he could make out only the first few meters, still lit by the faint auroral glow, of the narrow ribbon up which Spider was swiftly and smoothly climbing.

"Coming up to three-eighty," said Kingsley. "How is the power level?"

"Beginning to drop--down to eighty-five percent--the battery's starting to fade."

"Well, if it holds out for another twenty kilometers, it will have done its job. How do you feel?"

"I'm fine," Morgan answered. "If we could guarantee a display like this for all our passengers, we wouldn't be able to handle the crowds."

"Perhaps it could be arranged," laughed Kingsley. "We could ask Monsoon Control to dump a few barrels of electrons in the right places. Not their usual line of business, but they're good at improvising ... aren't they?"

Morgan chuckled but did not answer. His eyes were fixed on the instrument panel, where both power and rate of climb were now visibly dropping. But that was no cause for alarm; Spider had reached 385 kilometers out of the expected 400 and the booster battery still had some life in it.

At 390 kilometers, Morgan started to cut back the rate of climb, until Spider crept more and more slowly upward. Eventually, the capsule was barely moving, and it finally came to rest just short of 405 kilometers.

"I'm dropping the battery," Morgan reported. "Mind your heads."

A good deal of thought had been given to recovering that heavy and expensive battery, but there had been no time to improvise a braking system that would let it slide safely back. Fortunately, the impact area, just ten kilometers east of the Earth terminus, lay in dense jungle.

Morgan turned the safety key and then pressed the red button that fired the explosive charges; Spider shook briefly as they detonated. Then he switched to the internal battery, slowly released the friction brakes and again fed power into the drive motors.

The capsule started to climb on the last lap of its journey. But one glance at the instrument panel told Morgan that something was seriously wrong. Spider should have been rising at over 200 klicks; it was doing less than 100, even at full power.

"We're in trouble," Morgan reported back to Earth. "The charges blew--but the battery never dropped. Something's still holding it on."

It was unnecessary, of course, to add that the mission must now be aborted. Everyone knew perfectly well that Spider could not possibly reach the base of the tower, carrying over 200 kilos of dead weight.

A Bumpy Ride

Warren Kingsley's voice had regained its control; now it was merely dull and despairing.

"We're trying to stop the mechanic from shooting himself," he said. "But it's hard to blame him. He was interrupted by another rush job on the capsule and simply forgot to remove the safety strap."

So, as usual, it was human error. While the explosive links were being attached, the battery had been held in place by two metal bands. And only one of them had been removed. Recrimination was pointless. The only thing that mattered now was what to do next.

Morgan adjusted the external viewing mirror to its maximum downward tilt, but it was impossible to see the cause of the trouble. Now that the auroral display had faded, the lower part of the capsule was in total darkness and he had no means of illuminating it. But that problem, at least, could be readily solved. If Monsoon Control could dump kilowatts of infrared into the basement of the tower, it could easily spare him a few visible photons.

"We can use our own searchlights," said Kingsley, when Morgan passed on his request.

"No good--they'll shine straight into my eyes and I won't be able to see a thing. I want a light behind and above me--there must be somebody in the right position."

"I'll check," Kingsley answered, obviously glad to make some useful gesture. It seemed a long time before he called again; looking at his timer, Morgan was surprised to see that only three minutes had elapsed.

"Monsoon Control could manage it, but they'd have to retune and defocus--I think they're scared of frying you. But Kinte can light up immediately; they have a pseudo-white laser--and they're in the right position. Shall I tell them to go ahead?"

Morgan checked his bearings--let's see, Kinte would be very high in the west; that would be fine.

"I'm ready," he answered, and closed his eyes. Almost instantly, the capsule exploded with light.

Very cautiously, Morgan opened his eyes again. The beam was coming from high in the west, still dazzlingly brilliant despite its journey of almost 40,000 kilometers. It appeared to be pure white, but he knew that it was actually a blend of three sharply tuned lines in the red, green and blue parts of the spectrum.

After a few seconds' adjustment of the mirror, he managed to get a clear view of the offending strap, half a meter beneath his feet. The end that he could see was secured to the base of Spider by a large butterfly nut; all that he had to do was to unscrew that and the battery would drop off....

Morgan sat silently analyzing the situation for so many minutes that Kingsley called him again. For the first time, there was a trace of hope in his deputy's voice. "We've been doing some calculations, Van.... What do you think of this idea?"

Morgan heard him out, then whistled softly. "You're certain of the safety margin?" he asked.

"Of course," answered Kingsley, sounding somewhat aggrieved: Morgan hardly blamed him, but he was not the one who would be risking his neck.

"Well--I'll give it a try. But only for one second the first time."

"That won't be enough. Still, it's a good idea--you'll get the feel of it."

Gently, Morgan released the friction brakes that were holding Spider motionless on the tape. Instantly, he seemed to rise out of the seat, as weight vanished. He counted, "One, two!" and engaged the brakes again.

Spider gave a jerk and for a fraction of a second, Morgan was pressed uncomfortably down into the seat. There was an ominous squeal from the braking mechanism, then the capsule was at rest again, apart from a slight torsional vibration that quickly died away.

"That was a bumpy ride," said Morgan. "But I'm still here--and so is that infernal battery."

"So I warned you. You'll have to try harder. Two seconds at least."

Morgan knew that he could not outguess Kingsley, with all the figures and computing power at his command, but he still felt the need for some reassuring mental arithmetic. Two seconds of free fall--say half a second to put on the brakes--allowing one ton for the mass of Spider....

The question was: Which would go first--the strap retaining the battery or the tape that was holding him there 400 kilometers up in the sky? In the usual way, it would be no contest in a trial between hyperfilament and ordinary steel. But if he applied the brakes too suddenly--or they seized owing to this maltreatment--both might snap. And then he and the battery would reach the earth at very nearly the same time.

"Two seconds it is," he told Kingsley. "Here we go."

This time, the jerk was nerve-racking in its violence and the torsional oscillations took much longer to die out. Morgan was certain that he would have felt--or heard--the breaking of the strap. He was not surprised when a glance in the mirror confirmed that the battery was still there.

Kingsley did not seem too worried. "It may take three or four tries," he said.

After the third fall--Morgan felt he had dropped kilometers, but it was only about 50 meters--even Kingsley's optimism started to fade. It was obvious that the trick was not going to work.

"I'd like to send my compliments to the people who made that safety strap," said Morgan wryly. "Now what do you suggest? A three-second drop before I slam on the brakes?"

He could almost see Warren shake his head.

"Too big a risk. I'm not so much worried about the tape as the braking mechanism. It wasn't designed for this sort of thing."

"Well, it was a good try," Morgan answered. "But I'm not giving up yet. I'm damned if I'll be beaten by a simple butterfly nut, fifty centimeters in front of my nose. I'm going outside to get at it."

With the old-style space suits, reaching that butterfly nut would have been completely out of the question. Even with the Flexisuit that Morgan was now wearing, it might still be difficult--but at least he would make the attempt.

Very carefully, because more lives than his own now depended upon it, he rehearsed the sequence of events. He must check the suit, depressurize the capsule and open the hatch--which, luckily, was almost full length. Then he must release the safety belt, get down on his knees--if he could!--and reach for that butterfly nut. Everything depended upon its tightness. There were no tools of any kind aboard Spider, but Morgan was prepared to match his fingers--even in space gloves--against the average small wrench.

On The Porch

For the past five minutes, the only sound that had come from the capsule was a series of "Checks" as Morgan went through the suit routine with an expert up in Midway. That was now complete; everyone was waiting tensely for the crucial next step.

"Valving the air," said Morgan, his voice overlaid with a slight echo now that he had closed the visor of his helmet. "Capsule pressure zero. No problem with breathing."

A 30-second pause, then: "Opening the front door--there it goes. Now releasing the seat belt."

There was an unconscious stirring and murmuring among the watchers. In imagination, every one of them was up there in the capsule, aware of the void that had suddenly opened before him.

"Quick-release buckle operated. I'm stretching my legs. Not much headroom....

"Just getting the feel of the suit-- quite flexible--now I'm going out onto the porch--don't worry!--I've got the seat belt wrapped around my left arm....

"Phew! Hard work, bending as much as this. But I can see that butterfly nut, underneath the porch grille. I'm working out how to reach it....

"On my knees now--not very comfortable--

"I've got it! Now to see if it will turn...."

The listeners became rigid, silent-- then, in unison, relaxed with virtually simultaneous sighs of relief.

"No problem! I can turn it easily. Two revs already--any moment now--just a bit more--I can feel it coming off--look out down below!"

There was a burst of clapping and cheering; some people put their hands over their heads and cowered in mock terror. One or two, not fully understanding that the falling nut would not arrive for nearly five minutes and would descend ten kilometers to the east, looked genuinely alarmed.

Only Warren Kingsley failed to share the rejoicing.

The seconds dragged by ... one minute ... two minutes....

"It's no use," said Morgan at last, his voice thick with rage and frustration. "I can't budge the strap. The battery weight is holding it jammed in the threads. Those jolts we gave must have welded it to the bolt."

"Come back as quickly as you can," said Kingsley. "There's a new power cell on the way and we can manage a turnaround in less than an hour. So we can still get up to the tower in--oh, say, six hours. Barring any further accidents, of course."

Precisely, thought Morgan; and he would not care to take Spider up again without a thorough check of the much-abused braking mechanism. Nor would he trust himself to make a second trip; he was already feeling the strain of the past few hours and fatigue would soon be slowing down his mind and body, just when he needed maximum efficiency from both.

He was back in the seat now, but the capsule was still open to space and he had not yet refastened the safety belt. To do so would be to admit defeat; and that had never been easy for Morgan.

The unwinking glare of the Kinte laser, coming from almost immediately above, still transfixed him with its pitiless light. He tried to focus his mind upon the problem, as sharply as that beam was focused upon him.

All that he needed was a metal cutter--a hacksaw or a pair of shears--that could sever the retaining strap. Once again, he cursed the fact that there was no tool kit aboard Spider; even so, it would hardly have contained what he needed.

There were hundreds of kilowatt--hours of energy stored in Spider's own battery; could he use that in any way? He had a brief fantasy of establishing an arc and burning through the strap; but even if suitable heavy conductors were available--and, of course, they weren't--the main power supply was inaccessible from the control cab.

Warren and all the skilled brains gathered around him had failed to find any solution. He was on his own, physically and intellectually. It was, after all, the situation he had always preferred.

And then, just as he was about to reach out and close the capsule door, Morgan knew what he had to do. All the time, the answer had been right by his finger tips.

The Other Passenger

To Morgan, it seemed that a huge weight had lifted from his shoulders. He felt completely, irrationally confident.

This time, surely, it had to work.

Nevertheless, he did not move from his seat until he had planned his actions in minute detail. And when Kingsley, sounding a little anxious, once again urged him to hurry back, he gave an evasive answer. He did not wish to raise any false hopes--on Earth or in the tower.

"I'm trying an experiment," he said. "Leave me alone for a few minutes."

He picked up the fiber dispenser that he had used for so many demonstrations--the little spinnerette that, years ago, had allowed him to descend the face of Yakkagala. One change had been made for reasons of safety; the first meter of filament had been coated with a layer of plastic, so that it was no longer quite invisible and could be handled cautiously, even with bare fingers.

As Morgan looked at the little box in his hand, he realized how much he had come to regard it as a talisman--almost a good-luck charm.

Once more, he clambered out of the seat and knelt down on the metal grille of Spider's tiny porch to examine the cause of all the trouble. The offending bolt was only ten centimeters on the other side of the grid, and although its bars were too close together for him to put his hand through them, he had already proved that he could reach around it without too much difficulty.

He released the first meter of coated fiber and, using the ring at the end as a plumb bob, lowered it down through the grille. Tucking the dispenser itself firmly in a corner of the capsule, so that he could not accidentally knock it overboard, he then reached around the grille until he could grab the swinging weight. This was not as easy as he had expected, because even this remarkable space suit would not allow his arm to bend quite freely, and the ring eluded his grasp as it pendulumed back and forth.

After half a dozen attempts--tiring rather than annoying, because he knew that he would succeed sooner or later--he had looped the fiber around the shank of the bolt, just behind the strap it was still holding in place.

He released just enough filament from the spinnerette for the naked fiber to reach the bolt and to pass around it; then he drew both ends tight--until he felt the loop catch in the thread.

Morgan had never attempted this trick with a rod of tough alloy more than a centimeter thick and had no idea how long it would take. Bracing himself against the porch, he began to operate his invisible saw.

After five minutes, he was sweating heavily and could not tell if he had made any progress at all. He was afraid to slacken the tension, lest the fiber escape from the equally invisible slot it was--he hoped--slicing through the bolt. Several times Warren had called him, sounding more and more alarmed, and he had given a brief reassurance. Soon he would rest for a while, recover his breath--and explain what he was trying to do. This was the least that he owed to his anxious friends.

The calm but authoritative woman's voice that interrupted Morgan gave him such a shock that he almost let go of the precious fiber. The words were muffled by his suit, but that did not matter. He knew them all too well, though it had been months since he had last heard them.

"Dr. Morgan," said CORA. "Please lie down and relax for the next ten minutes."

"Would you settle for five?" he pleaded. "I'm rather busy at the moment."

CORA did not deign to reply; although there were units that could conduct simple conversations, this model was not among them.

Morgan kept his promise, breathing deeply and steadily for a full five minutes. Then he started sawing again.

"Dr. Morgan," said CORA. "You really must lie down for half an hour."

Morgan swore softly to himself.

"You're making a mistake, young lady," he retorted. "I'm feeling fine." But he was lying; CORA knew about the ache in his chest....

"Who the hell are you talking to, Van?" asked Kingsley.

"Just a passing angel," answered Morgan. "Sorry I forgot to switch off the mike. I'm going to take another rest."

"What progress are you making?"

"Can't say. But I'm sure the cut's pretty deep by this time. It must be...."

He wished that he could switch off CORA, but that, of course, was impossible, even if she had not been out of reach between his breastbone and the fabric of his space suit. A heart monitor that could be silenced was worse than useless--it was dangerous.

"Dr. Morgan," said CORA, now distinctly annoyed. "I really must insist. At least half an hour's complete rest."

This time, Morgan did not feel like answering. He knew that CORA was right; but she could not be expected to understand that his was not the only life involved.

The pain in his chest certainly seemed to be getting no worse; he decided to ignore both it and CORA and started to saw away, slowly but steadily, with the loop of fiber. He would keep going, he told himself grimly, just as long as was necessary.

Suddenly, Spider lurched violently as a quarter ton of dead weight ripped away, and Morgan was almost pitched out into the abyss. He dropped the spinnerette and grabbed for the safety belt.

Everything seemed to happen in dreamlike slow motion. He had no sense of fear, only an utter determination not to surrender to gravity without a fight. But he could not find the safety belt; it must have swung back into the cabin....

He was not even conscious of using his left hand, but suddenly he realized that it was clamped around the hinges of the open door. Yet still he did not pull himself back into the cabin; he was hypnotized by the sight of the falling battery, slowly rotating like some strange celestial body as it dwindled from sight. It took a long time to vanish completely; and not until then did Morgan drag himself to safety and collapse into his seat.

For a long time, he sat there, his heart hammering, awaiting CORA's next indignant protest. To his surprise, she was silent, almost as if she, too, had been equally startled. Well, he would give her no further cause for complaint; from now on, he would sit quietly at the controls, trying to relax his jangled nerves.

When he was himself again, he called the mountain.

"I've gotten rid of the battery," he said, and heard the cheers float up from Earth. "As soon as I've closed the hatch, I'll be on my way again. Tell Sessui and Company to expect me in just over an hour. And thank Kinte for the light--I don't need it now."

He repressurized the cabin, opened the helmet of his suit and treated himself to a long, cold sip of fortified orange juice. Then he engaged drive and released the brakes and lay back with a sense of overwhelming relief as Spider came up to full speed.

He had been climbing for several minutes before he realized what was missing. In anxious hope, he peered out at the metal grille of the porch. No, it was not there.

Well, he could always get another spinnerette to replace the one now following the discarded battery back to Earth; it was a small sacrifice for such an achievement. Strange, therefore, that he was so upset and unable fully to enjoy his triumph.

He felt that he had lost an old and faithful friend.

Fade Out

The fact that he was still only 30 minutes behind schedule seemed too good to be true; Morgan would have been prepared to swear that the capsule had halted for at least an hour.

When he passed the 500-kilometer mark, still going strong, there was a message of congratulation from the ground. "By the way," added Kingsley, "the game warden in the Ruhana Sanctuary's reported an aircraft crashing. We were able to reassure him--if we can find the hole, we may have a souvenir for you." Morgan had no difficulty in restraining his enthusiasm; he was glad to see the last of that battery. Now, if they could find the spinnerette--but that would be a hopeless task....

The first sign of trouble came at 550 kilometers. By now, the rate of ascent should have been almost 250 klicks; it was only 220. Slight though the discrepancy was--and it would make no appreciable difference to his arrival time--it worried Morgan.

When he was only 30 kilometers from the tower, he had diagnosed the problem and knew that this time there was absolutely nothing he could do about it. Although there should have been ample reserve, the battery was beginning to fade.

Perhaps those sudden jolts and restarts had brought on the malaise; possibly there was even some physical damage to the delicate components. Whatever the explanation, the current was slowly dropping and, with it, the capsule's speed.

There was consternation when Morgan reported the indicator readings back to the ground.

"I'm afraid you're right," Kingsley lamented, sounding almost in tears. "We suggest you cut speed back to one hundred klicks. We'll try to calculate battery life--though it can only be an educated guess."

Twenty-five kilometers to go--a mere 15 minutes, even at this reduced speed! If Morgan had been able to pray, he would have done so.

"We estimate you have between ten and twenty minutes, judging by the rate the current is dropping. It will be a close thing, I'm afraid."

"Shall I reduce speed again?"

"Not for the moment; we're trying to optimize your discharge rate, and this seems about right."

"Well, you can switch on your beam now. If I can't get to the tower, at least I want to see it."

Neither Kinte nor the other orbiting stations could help him, now that he wished to look up at the underside of the tower. This was a task for the searchlight on Sri Kanda itself, pointing vertically toward the zenith.

A moment later, the capsule was impaled by a dazzling beam from the heart of Taprobane. Only a few meters away--indeed, so close that he felt he could touch them--the three other guiding tapes were ribbons of light, converging toward the tower. He followed their dwindling perspective--and there it was....

Just 20 kilometers away! He should be there in a dozen minutes, coming up through the floor of that tiny square building he could see glittering in the sky.

At ten kilometers, there was a distinct change of pitch from the drive motors; Morgan had been expecting this and reacted to it at once. Without waiting for advice from the ground, he cut speed back to 50 klicks.

At five kilometers, he could see the constructional details of the tower--the catwalk and protective rails, the futile safety net provided as a sop to public opinion. Although he strained his eyes, he could not yet make out the air lock toward which he was now crawling with such agonizing slowness.

And then it no longer mattered. Two kilometers short of the goal, Spider's motors stalled completely. The capsule even slid downward a few meters before Morgan was able to apply the brakes.

Yet this time, to Morgan's surprise, Kingsley did not seem utterly downcast.

"You can still make it," he said. "Give the battery ten minutes to recuperate. There's still enough energy there for that last couple of kilometers."

Morgan gave the battery an extra minute for luck. To his relief, the motors responded strongly, with an encouraging surge of power. Spider got within half a kilometer of the tower before stalling again.

"Next time does it," said Kingsley, though it seemed to Morgan that his friend's confidence now sounded somewhat forced. "Sorry for all these delays...."

"Another ten minutes?" Morgan asked with resignation.

"I'm afraid so. And this time, use thirty-second bursts, with a minute between them. That way, you'll get the last erg out of the battery."

And out of me, thought Morgan. Strange that CORA had been quiet for so long. Still, this time he had not exerted himself physically; it only felt that way.

In his preoccupation with Spider, he had been neglecting himself. For the past hour, he had quite forgotten his zero-residue glucose-based energy tablets and the little plastic bulb of fruit juice. After he had sampled both, he felt much better and only wished that he could transfer some of the surplus calories to the dying battery.

Now for the moment of truth--the final exertion. Failure was unthinkable, when he was so close to the goal. The fates could not possibly be so malevolent, now that he had only a few hundred meters to go.

The capsule heaved itself upward in fits and starts, like a dying animal seeking its last haven. When the battery finally expired, the base of the tower seemed to fill half the sky.

But it was still 20 meters above him.

Theory Of Relativity

It was to Morgan's credit that he felt his own fate was sealed in the desolating moment when the last dregs of power were exhausted and the lights on Spider's display panel finally faded out. Not for several seconds did he remember that he had only to release the brakes and he would slide back to Earth. In three hours, he could be safely back in bed. No one would blame him for the failure of his mission; he had done all that was humanly possible.

For a brief while, he stared in a kind of dull fury at that inaccessible square, with the shadow of Spider projected upon it. His mind revolved a host of crazy schemes and rejected them all. If he still had his faithful little spinnerette--but there would have been no way of getting it to the tower. If the refugees possessed a space suit, someone could lower a rope to him--but there had been no time to collect a suit from the burning transporter.

Of course, if this were a video drama, and not a real-life problem, some heroic volunteer could sacrifice himself--better yet, herself--by going into the lock and tossing down a rope, using the 15 seconds of vacuum consciousness to save the others. It was some measure of Morgan's desperation that, for a fleeting moment, he even considered this idea before common sense reasserted itself.

From the time that Spider had given up the battle with gravity until Morgan finally accepted that there was nothing more that he could do, probably less than a minute elapsed. Then Warren Kingsley asked a question that, at such a moment, seemed an annoying irrelevance.

"Give us your distance again, Van--exactly how far are you from the tower?"

"What the hell does it matter? It could be a light-year."

There was a brief silence from the ground; then Kingsley spoke again: "It makes all the difference in the world. Did you say twenty meters?"

"Yes--that's about it."

Incredibly -- unmistakably -- Warren gave a clearly audible sigh of relief. There was even joy in his voice when he answered: "And all these years, Van, I thought that you were the chief engineer on this project. Suppose it is twenty meters exactly----"

Morgan's explosive shout prevented him from finishing the sentence. "What an idiot! Tell Sessui I'll dock in--oh, fifteen minutes."

"Fourteen point five, if you've guessed the distance right. And nothing on Earth can stop you now."

That was still a risky statement and Morgan wished that Kingsley hadn't made it. Docking adapters sometimes failed to latch together properly, because of minute errors in manufacturing tolerances. And, of course, there had never been a chance to test this particular system.

He felt only a slight embarrassment at his mental blackout. After all, under extreme stress, a man could forget his own telephone number, even his own date of birth.

It was all a matter of relativity. He could not reach the basement; but the basement would reach him--at its inexorable two kilometers a day.

Hard Dock

The record for one day's construction had been 30 kilometers, when the slimmest and lightest section of the tower was being assembled. Now that the most massive portion--the very root of the structure--was nearing completion in orbit, the rate was down to two kilometers. The approximately 15 minutes that it would take the tower to reach Spider would give Morgan time to check the adapter line-up and to mentally rehearse the rather tricky few seconds between confirming hard dock and releasing Spider's brakes. If he left them on for too long, there would be a very unequal trial of strength between the capsule and the moving megatons of the tower.

It was a long but relaxed 15 minutes--time enough, Morgan hoped, to pacify CORA. Toward the end, everything seemed to happen very quickly and, at the last moment, he felt like an ant about to be crushed in a stamping press, as the solid roof in the sky descended upon him. One second, the base of the tower was still meters away; an instant later, it appeared, he felt and heard the impact of the docking mechanism.

Many lives depended now upon the skill and care with which the engineers and mechanics, years ago, had done their work. If the couplings did not line up within the allowed tolerances; if the latching mechanism did not operate correctly; if the seal were not airtight; if the stand-by instrument battery were inoperative....

Then, like a signal of victory, the DOCKING COMPLETED sign flashed on the indicator board. Tower and capsule were firmly mated together. Morgan had only to climb a few rungs of ladder and he would have reached his goal.

Already, he could hear a faint tattoo of welcoming raps from the far side of the air lock. He undid his safety belt, climbed awkwardly onto the seat and started to ascend the ladder.

The bare, bleak cell was lit only by the solar-fluorescent panels that had been patiently trapping and releasing sunlight for more than a decade, against the emergency that had arrived at last. Their illumination revealed a scene that might have come from some old war; here were homeless and disheveled refugees from a devastated city, huddling in a bomb shelter with the few possessions they had been able to save.

Not many such refugees, however, would have carried bags labeled Projection, Lunar Hotel Corporation, Property of the Federal Republic of Mars, or the ubiquitous May/Not/Be Stowed In Vacuum. Nor would they have been so cheerful; even those who were lying down to conserve oxygen managed a smile and a languid wave. Morgan had just returned the salute when his legs buckled beneath him and everything blacked out.

Never before in his life had he fainted, and when the blast of cold oxygen revived him, his first emotion was one of acute embarrassment. His eyes came slowly into focus and he saw masked shapes hovering over him. For a moment, he wondered if he were in hospital; then brain and vision returned to normal. While he was still unconscious, his precious cargo must have been unloaded.

Those masks were the molecular sieves he had carried up to the tower; worn over nose and mouth, they would block the CO., but allow oxygen to pass. Simple yet technologically sophisticated, they would enable men to survive in an atmosphere that would otherwise cause rapid death. It required a little extra effort to breathe through them, but nature never gave something for nothing--and this was a very small price to pay.

Rather groggily, but refusing any help. Morgan got to his feet and was belatedly introduced to the men and women he had saved. One matter still worried him; while he was unconscious, had CORA delivered any of her set speeches?

"On behalf of all of us," said Professor Sessui, with sincerity yet with the obvious awkwardness of a man who was seldom polite to anyone, "I want to thank you for what you've done. We owe our lives to you."

Any logical or coherent reply to this would have smacked of false modesty, so Morgan used the excuse of adjusting his mask to mumble something unintelligible. He was about to start checking that all the equipment had been unloaded when Professor Sessui added, rather anxiously: "I'm sorry we can't offer you a chair--this is the best we can do." He pointed to a couple of instrument boxes, one on top of the other. "You really should take it easy."

The phrase was familiar; so CORA had spoken. There was a slightly embarrassed pause while Morgan registered this fact, and the others admitted that they knew, and he showed that he knew they knew--all without a word being uttered.

"That can of sealant," Morgan said, pointing to the smallest of the containers he had brought, "should take care of your leak. Spray it round the gasket of the air lock: it sets hard in a few seconds.

"Use the oxygen only when you have to; you may need it to sleep. There's a CO., mask for everyone and a couple of spares.

"And here's food and water for three days--that should be plenty. The transporter from 10K should be here tomorrow. As for the Medikit--I hope you won't need that at all...."

He paused for breath; it was not easy to talk while wearing a CO2 filter and he felt an increasing need to conserve his strength. But he still had one further job to do--and the sooner the better.

Morgan turned to driver-pilot Chang and said quietly, "Please help me suit up again. I want to inspect the tracks."

"That's only a thirty-minute suit you're wearing!"

"I'll need ten minutes--fifteen at the most."

"Dr. Morgan, I'm a space-qualified operator, you're not. No one's allowed to go out in a thirty-minute suit without a spare pack or an umbilical. Except in an emergency, of course."

"I want to look at the damage," he answered, "and examine the tracks. It would be a pity if the people from 10K couldn't reach you because they weren't warned of some obstacle."

Chang was clearly not too happy about the situation (what had that gossiping CORA jabbered while he was unconscious?) but raised no further arguments as he followed Morgan into the north lock.

"I'm going to take a quick walk around the tower," said Morgan, "and I'll describe any damage so you can report to Midway. It won't take more than ten minutes. And if it does--well, don't try to get me back."

Driver-pilot Chang's reply, as he closed the inner door of the air lock, was very practical and very brief.

"How the hell could I?" he asked.

View From The Balcony

The outer door of the north air lock opened without difficulty, framing a rectangle of complete darkness. Running horizontally across that darkness was a line of fire--the protective handrail of the catwalk, blazing in the beam of the searchlight pointed straight up from the mountain so far below.

Morgan took a deep breath and flexed the suit. He felt perfectly comfortable and waved to Chang, peering at him through the window of the inner door. Then he stepped out of the tower.

The catwalk that surrounded the basement was a metal grille about two meters wide; beyond it, the safety net had been stretched out for another 30 meters. The portion that Morgan could see had caught nothing whatsoever during its years of patient waiting.

He started his circumnavigation of the tower, shielding his eyes against the glare blasting up from underfoot. The oblique lighting showed up every least bump and imperfection in the surface, which stretched above him like a roadway to the stars--and, in a sense, it was.

As he had hoped and expected, the explosion on the far side of the tower had caused no damage here; that would have required an atomic bomb, not a mere electrochemical one. The twin grooves of the track, now awaiting their first arrival, stretched endlessly upward in their pristine perfection.

Taking his time, and keeping close to the sheer face of the tower, Morgan walked slowly westward until he came to the first corner. As he turned, he looked back at the open door of the air lock and the--relative, indeed!--safety that it represented. Then he continued boldly along the blank wall of the west face.

The west face was exactly like the north one--there was no sign of damage, even though it was closer to the scene of the explosion.

Checking the impulse to hurry--after all, he had been outside for only three minutes--Morgan strolled on to the next corner. Even before he turned it, he could see that he was not going to complete his planned circuit of the tower. The catwalk had been ripped off and was dangling out in space, a twisted tongue of metal. The safety net had vanished altogether, doubtless torn away by the falling transporter.

I won't press my luck, Morgan told himself. But he could not resist peering round the corner, holding on to the section of the guardrail that remained.

There was a good deal of debris stuck in the track and the face of the tower had been discolored by the explosion. But as far as Morgan could see, even here there was nothing that could not be put right in a couple of hours by a few men with cutting torches. He gave a careful description to Chang, who expressed relief and urged Morgan to get back into the tower as soon as possible.

When he had walked back to the open door of the air lock, he stood for a few final moments beside the guardrail, drenched by the fountain of light leaping up from the summit of Sri Kanda far below. It threw his own immensely elongated shadow directly along the tower, vertically upward toward the stars. That shadow must stretch for thousands of kilometers, and it occurred to Morgan that it might even reach the transporter now dropping swiftly down from the 10K station. If he waved his arms, the rescuers might be able to see his signals; he could talk to them in Morse code....

This amusing fantasy inspired a more serious thought. Would it be best for him to wait here, with the others, and not risk the return to Earth in Spider? But the journey up to Midway, where he could get good medical attention, would take more than a day. That was not a sensible alternative, since he could be back on Sri Kanda in less than three hours.

He patted the smooth, unyielding surface of the tower, more enormous in comparison with him than an elephant with an amoeba. But no amoeba could ever conceive of an elephant--still less create one.

"See you on Earth in ten months," Morgan whispered, and slowly closed the air-lock door behind him.

The Last Dawn

Morgan was back in the basement for only five minutes; this was no time for social amenities and he did not wish to consume any of the precious oxygen he had brought here with such difficulty. He shook hands all round and scrambled back into Spider.

It was good to breathe again without a mask--better yet to know that his mission had been a complete success and that in less than three hours he would be safely back on Earth. Yet after all the effort that had gone into reaching the tower, he was reluctant to cast off again and to surrender once more to the pull of gravity--even though it was now taking him home. But presently, he released the docking latches and started to fall downward, becoming weightless for several seconds.

When the speed indicator reached 300 klicks, the automatic mechanical braking system came on and weight returned. The brutally depleted battery would be recharging now, but it must have been damaged beyond repair and would have to be taken out of service.

There was an ominous parallel here; Morgan could not help thinking of his own overstrained body, but a stubborn pride still kept him from asking for a doctor on stand-by. He had made a little bet with himself; he would do so only if CORA spoke again.

She was silent now, as he dropped swiftly through the night. Morgan felt totally relaxed and left Spider to look after itself while he admired the heavens. Few spacecraft provided so panoramic a view, and not many men could ever have seen the stars under such superb conditions. The auroral veil had vanished completely, the searchlight had been extinguished and there was nothing left to challenge the constellations.

Except, of course, the stars that man himself had made. Almost directly overhead was the dazzling beacon of Ashoka, only a few hundred kilometers from the tower complex. Halfway down in the east was Confucius, much lower yet Kamehameha, while high up from the west shone Kinte and Imhotep. These were merely the brightest signposts along the equator; there were literally scores of others, all of them far more brilliant than Sirius. How astonished one of the old astronomers would have been to see this necklace around the sky. And how bewildered he would have become when, after an hour or so's observation, he discovered that they were quite immobile--neither rising nor setting, while the familiar stars drifted past in their ancient courses.

As he stared at the diamond necklace stretched across the sky, Morgan's sleepy mind slowly transformed it into something far more impressive. With only a slight effort of the imagination, those man-made stars became the lights of a titanic bridge....

He drifted into still wilder fantasies. What was the name of the bridge into Valhalla, across which the heroes of the Norse legends passed from this world to the next? He could not remember, but it was a glorious dream.

And had other creatures, long before man, tried in vain to span the skies of their own worlds? He thought of the splendid rings encircling Saturn, the ghostly arches of Uranus and Neptune. Although he knew perfectly well that none of these worlds had ever felt the touch of life, it amused him to think that here were the shattered fragments of bridges that had failed.

He wanted to sleep, but against his will, imagination had seized upon the idea. Like a dog that had just discovered a new bone, it would not let go.

The concept was not absurd; it was not even original. Many of the synchronous stations were already kilometers in extent or linked by cables that stretched along appreciable fractions of their orbit. To join them together, thus forming a ring completely around the world, would be an engineering task much simpler than the building of the tower and involving much less material.

No--not a ring, a wheel. This tower was only the first spoke. There would be others (four? six? a score?) spaced along the equator. When they were all connected rigidly up there in orbit, the problems of stability that plagued a single tower would vanish. Africa, South America, the Gilbert Islands, Indonesia--they could all provide locations for Earth terminals, if desired.

For someday, as materials improved and knowledge advanced, the towers could be made invulnerable even to the worst hurricanes, and mountain sites would no longer be necessary. If he had waited another 100 years, perhaps he need not have disturbed the Mahanayake Thero....

While he was dreaming, the thin crescent of the waning moon had lifted unobtrusively above the eastern horizon, already aglow with the first hint of dawn. Earthshine lit the entire lunar disk so brilliantly that Morgan could see much of the night-land detail; he strained his eyes in the hope of glimpsing that loveliest of sights, never seen by earlier ages--a star within the arms of the crescent moon. But none of the cities of man's second home was visible tonight.

Only 200 kilometers--less than an hour to go. There was no point in trying to keep awake; Spider had automatic stand-by mechanical terminal programming and would touch gently down without disturbing his sleep....

The pain woke him first; CORA was a fraction of a second later.

"Don't try to move," she said soothingly. "I've radioed for help. The ambulance is on the way."

That was funny. But don't laugh, Morgan ordered himself; she's only doing her best. He felt no fear; though the pain beneath his breastbone was intense, it was not incapacitating. He tried to focus his mind upon it and the very act of concentration relieved the symptoms. Long ago, he had discovered that the best way of handling pain was to study it objectively.

Warren was calling him, but the words were far away and had little meaning. He could recognize the anxiety in his friend's voice and wished that he could do something to alleviate it; but he had no strength left to deal with this problem--or with any other.

Now he could not even hear the words; a faint but steady roar had obliterated all other sounds. Though he knew that it existed only in his mind--or the labyrinthine channels of his ears--it seemed completely real; he could believe that he was standing at the foot of some great waterfall....

It was growing fainter, softer--more musical. And suddenly he recognized it. How pleasant to hear once more, on the silent frontier of space, the sound he remembered from his very first visit to Yakkagala!

Gravity was drawing him home again, as through the centuries its invisible hand had shaped the trajectories of the Fountains of Paradise. But he had created something that gravity could never recapture, as long as men possessed the wisdom and the will to preserve it.

How cold his legs were! What had happened to Spider's life-support system? But soon it would be dawn; then there would be warmth enough.

The stars were fading, far more swiftly than they had any right to do. That was strange; though the day was almost here, everything around him was growing dark. And the fountains were sinking back into the Earth, their voices becoming fainter ... fainter ... fainter....

And now there was another voice, but Vannevar Morgan did not hear it. Between brief, piercing bleeps, CORA cried to the approaching dawn:

Help! Will Anyone Who Hears MePlease Come At Once!This Is a Cora Emergency!

Help! Will Anyone Who Hears MePlease Come At Once!

•

She was still calling when the sun came up and its first rays caressed the summit of the mountain that had once been sacred. Far below, the shadow of Sri Kanda leaped forth upon the clouds, its truncated cone otherwise unblemished by any act of man.

There were no pilgrims now, to watch that symbol of eternity lie across the face of the awakening land. But millions would see it, in the centuries ahead, as they rode in comfort and safety to the stars.

"Was he gambling with other lives as well as his own, just to satisfy his own selfish pride?"

"Slowly, in the depths of the mirror, a faint red glow began to burn, and spread, and consume the stars."

This is the conclusion of "The Fountains of Paradise."