The Fountains of Paradise

38. A Place of Silent Storms

(Extract from Professor Martin Sessui's address, on receiving the Nobel Prize for Physics, Stockholm, 16 December 2154.)

Between Heaven and Earth lies an invisible region of which the old philosophers never dreamed. Not until the dawn of the twentieth century – to be precise, on 12 December 1901 – did it make its first impact upon human affairs.

On that day, Guglielmo Marconi radioed the three dots of the Morse letter “S” across the Atlantic. Many experts had declared this to be impossible, as electromagnetic waves could travel only in straight lines, and would be unable to bend round the curve of the globe. Marconi's feat not only heralded the age of world-wide communications, but also proved that, high up in the atmosphere, there exists an electrified mirror, capable of reflecting radio waves back to earth.

The Kennelly-Heaviside Layer, as it was originally named, was soon found to be a region of great complexity, containing at least three main layers, all subject to major variations in height and intensity. At their upper limit they merge into the Van Allen Radiation Belts, whose discovery was the first triumph of the early space age.

This vast region, beginning at a height of approximately fifty kilometres and extending outwards for several radii of the Earth, is now known as the ionosphere; its exploration by rockets, satellites and radio waves has been a continuing process for more than two centuries. I should like to pay a tribute to my precursors in this enterprise – the Americans Tuve and Breit, the Englishman Appleton, the Norwegian Stшrmer – and, especially, the man who, in 1970, won the very award I am now so honoured to accept, your countryman Hannes Alfvйn…

The ionosphere is the wayward child of the sun; even now, its behaviour is not always predictable. In the days when long-range radio depended upon its idiosyncrasies it saved many lives – but more men than we shall ever know were doomed when it swallowed their despairing signals without trace.

For less than one century, before the communications satellites took over, it was our invaluable but erratic servant – a previously unsuspected natural phenomenon, worth countless billions of dollars to the three generations who exploited it.

Only for a brief moment in history was it of direct concern to mankind. And yet – if it had never existed, we should not be here! In one sense, therefore, it was of vital importance even to pre-technological humanity, right back to the first ape-man – indeed, right back to the first living creatures on this planet. For the ionosphere is part of the shield that protects us from the sun's deadly X-ray and ultra-violet radiations. If they had penetrated to sea level, perhaps some kind of life might still have arisen on earth; but it would never have evolved into anything remotely resembling us…

Because the ionosphere, like the atmosphere below it, is ultimately controlled by the sun, it too has its weather. During times of solar disturbance it is blasted by planet-wide gales of charged particles, and twisted into loops and whirls by the earth's magnetic field. On such occasions it is no longer invisible, for it reveals itself in the glowing curtains of the aurora – one of Nature's most awesome spectacles, illuminating the cold polar nights with its eerie radiance.

Even now, we do not understand all the processes occurring in the ionosphere. One reason why it has proved difficult to study is because all our rocket and satellite-borne instruments race through it at thousands of kilometres an hour; we have never been able to stand still to make observations! Now, for the very first time, the construction of the proposed Orbital Tower gives us a chance of establishing fixed observatories in the ionosphere. It is also possible that the Tower may itself modify the characteristics of the ionosphere – though it will certainly not, as Dr. Bickerstaff has suggested, short-circuit it!

Why should we study this region, now that it is no longer important to the communications engineer? Well, apart from its beauty, its strangeness and its scientific interest, its behaviour is closely linked with that of the sun – the master of our destiny. We know now that the sun is not the steady, well-behaved star that our ancestors believed; it undergoes both long and short-period fluctuations. At the present time it is still emerging from the so-called “Maunder Minimum” of 1645 to 1715; as a result, the climate now is milder than at any time since the Early Middle Ages. But how long will this upswing last? Even more important, when will the inevitable downturn begin, and what effect will this have upon climate, weather and every aspect of human civilization – not only on this planet, but on the others as well? For they are all children of the sun…

Some very speculative theories suggest that the sun is now entering a period of instability which may produce a new Ice Age, more universal than any in the past. If this is true, we need every scrap of information we can get to prepare for it. Even a century's warning might not be long enough.

The ionosphere helped to create us; it launched the communications revolution; it may yet determine much of our future. That is why we must continue the study of this vast, turbulent arena of solar and electric forces – this mysterious place of silent storms.

39. The Wounded Sun

The last time that Morgan had seen Dev, his nephew had been a child. Now he was a boy in his early teens; and at their next meeting, at this rate, he would be a man.

The engineer felt only a mild sense of guilt. Family ties had been weakening for the last two centuries: he and his sister had little in common except the accident of genetics. Though they exchanged greetings and small talk perhaps half-a-dozen times a year, and were on the best of terms, he was not even sure when and where they had last met.

Yet when he greeted the eager, intelligent boy (not in the least overawed, it seemed, by his famous uncle) Morgan was aware of a certain bitter-sweet wistfulness. He had no son to continue the family name; long ago, he had made that choice between Work and Life which can seldom be avoided at the highest levels of human endeavour. On three occasions – not including the liaison with Ingrid – he might have taken a different path; but accident or ambition had deflected him.

He knew the terms of the bargain he had made, and he accepted them; it was too late now to grumble about the small print. Any fool could shuffle genes, and most did. But whether or not History gave him credit, few men could have achieved what he had done – and was about to do.

In the last three hours, Dev had seen far more of Earth Terminus than any of the usual run of VIPs. He had entered the mountain at ground level, along the almost completed approach to the South Station, and had been given the quick tour of the passenger and baggage handling facilities, the control centre, and the switching yard where capsules would be routed from the East and West DOWN tracks to the North and South up ones. He had stared up the five-kilometre-long shaft – like a giant gun barrel aimed at the stars, as several hundred reporters had already remarked in hushed voices – along which the lines of traffic would rise and descend. And his questions had exhausted three guides before the last one had thankfully handed him over to his uncle.

“Here he is, Van,” said Warren Kingsley as they arrived via the high-speed elevator at the truncated summit of the mountain. “Take him away before he grabs my job.”

“I didn't know you were so keen on engineering, Dev.”

The boy looked hurt, and a little surprised. “Don't you remember, Uncle – that No 12 Meccamax you gave me on my tenth birthday?”

“Of course – of course. I was only joking.” (And, to tell the truth, he had not really forgotten the construction set; it had merely slipped his mind for the moment.) “You're not cold up here?” Unlike the well-protected adults, the boy had disdained the usual light thermocoat.

“No – I'm fine. What kind of jet is that? When are you going to open up the shaft? Can I touch the tapes?”

“See what I mean?” chuckled Kingsley.

“One: that's Sheik Abdullah's Special – his son Feisal is visiting. Two: we'll keep this lid on until the Tower reaches the mountain and enters the shaft – we need it as a working platform, and it keeps out the rain. Three: you can touch the tapes if you want to – don't run – it's bad for you at this altitude!”

“If you're twelve, I doubt it,” said Kingsley towards Dev's rapidly receding back. Taking their time, they caught up with him at the East Face anchor.

The boy was staring, as so many thousands of others had already done, at the narrow band of dull grey that rose straight out of the ground and soared vertically into the sky. Dev's gaze followed it up – up – up – until his head was tilted as far back as it would go. Morgan and Kingsley did not follow suit, though the temptation, after all these years, was still strong. Nor did they warn him that some visitors got so giddy that they collapsed and were unable to walk away without assistance.

The boy was tough: he gazed intently at the zenith for almost a minute, as if hoping to see the thousands of men and millions of tons of material poised there beyond the deep blue of the sky. Then he closed his eyes with a grimace, shook his head, and looked down at his feet for an instant, as if to reassure himself that he was still on the solid, dependable earth.

He reached out a cautious hand, and stroked the narrow ribbon linking the planet with its new moon.

“What would happen,” he asked, “if it broke?”

That was an old question; most people were surprised at the answer.

“Very little. At this point, it's under practically no tension. If you cut the tape it would just hang there, waving in the breeze.”

Kingsley made an expression of distaste; both knew, of course, that this was a considerable over-simplification. At the moment, each of the four tapes was stressed at about a hundred tons – but that was negligible compared to the design loads they would be handling when the system was in operation and they had been integrated into the structure of the Tower. There was no point, however, in confusing the boy with such details.

Dev thought this over; then he gave the tape an experimental flick, as if he hoped to extract a musical note from it. But the only response was an unimpressive “click” that instantly died away.

“If you hit it with a sledge-hammer,” said Morgan, “and came back about ten hours later, you'd be just in time for the echo from Midway.”

“Not any longer,” said Kingsley. “Too much damping in the system.”

“Don't be a spoil-sport, Warren. Now come and see something really interesting.”

They walked to the centre of the circular metal disc that now capped the mountain and sealed the shaft like a giant saucepan lid. Here, equidistant from the four tapes down which the Tower was being guided earthwards, was a small geodesic hut, looking even more temporary than the surface on which it had been erected. It housed an oddly-designed telescope, pointing straight upwards and apparently incapable of being aimed in any other direction.

“This is the best time for viewing, just before sunset; then the base of the Tower is nicely lit up.”

“Talking of the sun,” said Kingsley, “just look at it now. It's even clearer than yesterday.” There was something approaching awe in his voice, as he pointed at the brilliant flattened ellipse sinking down into the western haze. The horizon mists had dimmed its glare so much that one could stare at it in comfort.

Not for more than a century had such a group of Spots appeared; they stretched across almost half the golden disc, making it seem as if the sun had been stricken by some malignant disease, or pierced by falling worlds. Yet not even mighty Jupiter could have created such a wound in the solar atmosphere; the largest spot was a quarter of a million kilometres across, and could have swallowed a hundred Earths.

“There's another big auroral display predicted for tonight – Professor Sessui and his merry men certainly timed it well.”

“Let's see how they're getting on,” said Morgan, as he made some adjustments to the eye-piece. “Have a look, Dev.”

The boy peered intently for a moment, then answered: “I can see the four tapes, going inwards – I mean upwards – until they disappear.”

“Nothing in the middle?”

Another pause. “No – not a sign of the Tower.”

“Correct – it's still six hundred kilometres up, and we're on the lowest power of the telescope. Now I'm going to zoom. Fasten your seatbelt.”

Dev gave a little laugh at the ancient clichй, familiar from dozens of historical dramas. Yet at first he could see no alteration, except that the four lines pointing towards the centre of the field were becoming a little less sharp. It took him a few seconds to realise that no change could be expected as his point of view hurtled upwards along the axis of the system; the quartet of tapes would look exactly the same at any point along its length.

Then, quite suddenly, it was there, taking him by surprise even though he had been expecting it. A tiny bright spot had materialised in the exact centre of the field; it was expanding as he watched it, and now for the first time he had a real sensation of speed.

A few seconds later, he could make out a small circle – no, now both brain and eye agreed that it was a square. He was looking directly up at the base of the Tower, crawling earthwards along its guiding tapes at a couple of kilometres a day. The four tapes had now vanished, being far too small to be visible at this distance. But that square fixed magically in the sky continued to grow, though now it had become fuzzy under the extreme magnification.

“What do you see?” asked Morgan.

“A bright little square.”

“Good – that's the underside of the tower, still in full sunlight. When it's dark down here you can see it with the naked eye for another hour before it enters the earth's shadow. Now, do you see anything else?”

“Nooo…” replied the boy, after a long pause.

“You should. There's a team of scientists visiting the lowest section to set up some research equipment. They've just come down from Midway. If you look carefully you'll see their transporter – it's on the south track – that will be the right side of the picture. Look for a bright spot, about a quarter the size of the Tower.”

“Sorry, Uncle – I can't find it. You have a look.”

“Well, the seeing may have got worse. Sometimes the Tower disappears completely though the atmosphere may look -”

Even before Morgan could take Dev's place at the eyepiece, his personal receiver gave two shrill double beeps. A second later, Kingsley's alarm also erupted.

It was the first time the Tower had ever issued a four-star emergency alert.

40. The End of the Line

No wonder they called it the “Transiberian Railway”. Even on the easy downhill run, the journey from Midway Station to the base of the Tower lasted fifty hours.

One day it would take only five, but that still lay two years in the future, when the tracks were energised and their magnetic fields activated. The inspection and maintenance vehicles that now ran up and down the faces of the Tower were propelled by old-fashioned tyres, gripping the interior of the guidance slots. Even if the limited power of the batteries permitted, it was not safe to operate such a system at more than five hundred kilometres an hour.

Yet everyone had been far too busy to be bored. Professor Sessui and his three students had been observing, checking their instruments, and making sure that no time would be wasted when they transferred into the Tower. The capsule driver, his engineering assistant, and the one steward who comprised the entire cabin staff were also fully occupied, for this was no routine trip. The “Basement”, twenty-five thousand kilometres below Midway – and now only six hundred kilometres from Earth – had never been visited since it was built. Until now, there had been no purpose in going there, since the handful of monitors had never reported anything amiss. Not that there was much to go wrong, as the Basement was merely a fifteen-metre-square pressurised chamber – one of the scores of emergency refuges at intervals along the Tower.

Professor Sessui had used all his considerable influence to borrow this unique site, now crawling down through the ionosphere at two kilometres a day towards its rendezvous with Earth. It was essential, he had argued forcibly, to get his equipment installed before the peak of the current sunspot maximum.

Already, solar activity had reached unprecedented levels, and Sessui's young assistants often found it hard to concentrate on their instruments; the magnificent auroral displays outside were too much of a distraction. For hours on end, both northern and southern hemispheres were filled with slowly moving curtains and streamers of greenish light, beautiful and awe-inspiring – yet only a pale ghost of the celestial firework displays taking place around the poles. It was rare indeed for the aurora to wander so far from its normal domains; only once in generations did it invade the equatorial skies.

Sessui had driven his students back to work with the admonition that they would have plenty of time for sight-seeing during the long climb back to Midway. Yet it was noticeable that even the Professor himself sometimes stood at the observation window for minutes at a time, entranced by the spectacle of the burning heavens.

Someone had christened the project “Expedition to Earth” – which, as far as distance was concerned, was ninety-eight percent accurate. As the capsule crawled down the face of the Tower at its miserable five hundred klicks, the increasing closeness of the planet beneath made itself obvious. For gravity was slowly increasing, from the delightful less-than-lunar buoyancy of Midway to almost its full terrestrial value. To any experienced space traveller, this was strange indeed: feeling any gravity before the moment of atmospheric entry seemed a reversal of the normal order of things.

Apart from complaints about the food, stoically endured by the overworked steward, the journey had been devoid of incident. A hundred kilometres from the Basement, the brakes had been gently applied and speed had been halved. It was halved again at fifty kilometers – for, as one of the students remarked: “Wouldn't it be embarrassing if we ran off the end of the track?”

The driver (he insisted on being called pilot) retorted that this was inpossible, as the guidance slots down which the capsule was falling terminated several metres short of the Tower's end; there was also an elaborate buffer system, just in case all four independent sets of brakes failed to work. And everyone agreed that the joke, besides being perfectly ridiculous, was in extremely poor taste.

41. Meteor

The vast artificial lake known for two thousand years as the Sea of Paravana lay calm and peaceful beneath the stone gaze of its builder. Though few now visited the lonely statue of Kalidasa's father, his work, if not his fame, had outlasted that of his son; and it had served his country infinitely better, bringing food and drink to a hundred generations of men. And to many more generations of birds, deer, buffalo, monkeys and their predators, like the sleek and well-fed leopard now drinking at the water's edge. The big cats were becoming rather too common and were inclined to be a nuisance, now that they no longer had anything to fear from hunters. But they never attacked men, unless they were cornered or molested.

Confident of his security, the leopard was leisurely drinking his fill, as the shadows round the lake lengthened and twilight advanced from the east. Suddenly, he pricked up his ears and became instantly alert; but no mere human senses could have detected any change in land, water or sky. The evening was as tranquil as ever.

And then, directly out of the zenith, came a faint whistling that grew steadily to a rumbling roar, with tearing, ripping undertones, quite unlike that of a re-entering spacecraft. Up in the sky something metallic was sparkling in the last rays of the sun, growing larger and larger and leaving a trail of smoke behind it. As it expanded, it disintegrated; pieces shot off in all directions, some of them burning as they did so. For a few seconds an eye as keen as the leopard's might have glimpsed a roughly cylindrical object, before it exploded into a myriad fragments. But the leopard did not wait for the final catastrophe; it had already disappeared into the jungle.

The Sea of Paravana erupted in sudden thunder. A geyser of mud and spray shot a hundred metres into the air – a fountain far surpassing those of Yakkagala, and one indeed almost as high as the Rock itself. It hung suspended for a moment in futile defiance of gravity, then tumbled back into the shattered lake.

Already, the sky was full of waterfowl wheeling in startled flight. Almost as numerous, flapping among them like leathery pterodactyls who had somehow survived into the modern age, were the big fruit-bats who normally took to the air only after dusk. Now, equally terrified, birds and bats shared the sky together.

The last echoes of the crash died away into the encircling jungle; silence swiftly returned to the lake. But long minutes passed before its mirror surface was restored and the little waves ceased to scurry back and forth beneath the unseeing eyes of Paravana the Great.

42. Death in Orbit

Every large building, it is said, claims a life; fourteen names were engraved on the piers of the Gibraltar Bridge. But thanks to an almost fanatical safety campaign, casualties on the Tower had been remarkably low. There had, indeed, been one year without a single death.

And there had been one year with four – two of them particularly harrowing. A space-station assembly supervisor, accustomed to working under zero gravity, had forgotten that though he was in space he was not in orbit – and a life-time's experience had betrayed him. He had plummeted more than fifteen thousand kilometres, to burn up like a meteor upon entry into the atmosphere. Unfortunately his suit radio had remained switched on during those last few minutes…

It was a bad year for the Tower; the second tragedy had been much more protracted, and equally public. An engineer on the counterweight, far beyond synchronous orbit, had failed to fasten her safety belt properly – and had been flicked off into space like a stone from a sling. She was in no danger, at this altitude, either of falling back to earth or of being launched on an escape trajectory; unfortunately her suit held less than two hours' air. There was no possibility of rescue at such short notice; and despite a public outcry, no attempt was made. The victim had co-operated nobly. She had transmitted her farewell messages, and then – with thirty minutes of oxygen still unused – had opened her suit to vacuum. The body was recovered a few days later, when the inexorable laws of celestial mechanics brought it back to the perigee of its long ellipse.

These tragedies flashed through Morgan's mind as he took the highspeed elevator down to the Operations Room, closely followed by a sombre Warren Kingsley and the now almost forgotten Dev. But this catastrophe was of an altogether different type, involving an explosion at or near the Basement of the Tower. That the transporter had fallen to earth was obvious, even before the garbled report had been received of a “giant meteor shower” somewhere in central Taprobane.

It was useless to speculate until he had more facts; and in this case, where all the evidence had probably been destroyed, they might never be available. He knew that space accidents seldom had a single cause; they were usually the result of a chain of events, often quite harmless in themselves. All the foresight of the safety engineers could not guarantee absolute reliability, and sometimes their own over-elaborate precautions contributed to disaster. Morgan was not ashamed of the fact that the safety of the project now concerned him far more than any loss of life. Nothing could be done about the dead, except to ensure that the same accident could never happen again. But that the almost completed Tower might be endangered was a prospect too appalling to contemplate.

The elevator floated to a halt, and he stepped out into the Operations Room – just in time for the evening's second stunning surprise.

43. Fail-Safe

Five kilometres from the terminus, driver-pilot Rupert Chang had reduced speed yet again. Now, for the first time, the passengers could see the face of the Tower as something more than a featureless blur dwindling away to infinity in both directions. Upwards, it was true, the twin grooves along which they were riding still stretched forever-or at least for twenty-five thousand kilometres, which on the human scale was much the same. But downwards, the end was already in sight. The truncated base of the Tower was clearly silhouetted against the verdant green background of Taprobane, which it would reach and unite with in little more than a year.

Across the display panel, the red ALARM symbols flashed yet again. Chang studied them with a frown of annoyance, then pressed the RESET button. They flickered once, then vanished.

The first time this had happened, two hundred kilometres 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 pure vacuum environment for which it had been designed; the ionospheric 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; Midway approved, and in any case there was no alternative.

Battery condition was, perhaps, the item that concerned him most. The nearest charging point was two thousand kilometres 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 ninety percent of its gravitational energy had been pumped back into the batteries. Now that they were fully charged, the surplus hundreds 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 had 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 kilometre 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 ionospheric 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; it was the first time that Chang had ever listened with relief to the unmistakeable shriek of atmosphere escaping from a space vehicle; he hoped it would also be the last.

He dared not rely on the automatic braking sequence as the vehicle finally crawled into the terminus; fortunately, he had been well rehearsed and recognised all the visual signals, so that he was able to stop within a centimetre of the docking adapter. In frantic haste, the airlocks were coupled together, 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 airlock 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 bleak, fifteen-metre square chamber, with considerably fewer amenities than a well-furnished prison cell, and hope that the fire would burn itself out. Perhaps 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. Though 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 twenty-five thousand kilometres 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 realise that their miraculous escape might have been wholly in vain.

44. A Cave in the Sky

Deep inside the mountain, amid the display and communications equipment of the Earth Operations Centre, 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 downwards for another sixty 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 a hundred times the elevation of this mountain – had been sealed off to form a single square chamber, fifteen metres on a side.

“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 airlocks – 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, in the section of the Tower that would eventually become part of Earth Terminus itself.

“Tilt the underside towards me,” Morgan ordered.

The Tower toppled, in a falling arc of light, and lay floating horizontally in mid-air with its lower end towards Morgan. Now he could see all the details of the twenty-metre-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 airlocks, were the hatches that allowed access from below. The only problem was to reach them – six hundred kilometres up in the sky.

“Life support?”

The airlocks faded back into the structure; the visual emphasis moved to a small cabinet at the centre of the chamber.

“That's the problem, Doctor,” the Duty Officer answered sombrely. “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 own soul. The euphoria of discovering that the lost transporter's occupants were all still alive faded swiftly away. Even if there was 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 direct – the Basement emergency phone only goes to Midway. No problem, though.”

That turned out to be not completely true. When the connexion was made, Driver-Pilot Chang came on the line.

“I'm sorry,” he said, “the Professor is busy.”

After a moment's incredulous silence Morgan replied, pausing between each word and emphasising 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 spectroscope 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 last week with him. He's – well, I guess you could say single-minded. It took three of us to stop him 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, co-operating 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.”

It now occurred to him that, in any event, Chang could probably give a much more useful report than the Professor. Though the driver-pilot's insistence on the second half of his title often caused derision among genuine astrologers, he was a highly skilled technician with a good training in mechanical and electrical engineering.

“There's not much to say. We had such short notice that there was no time to save anything – except that damned spectrometer. Frankly, I never thought we'd make it through the airlock. We have the clothes we're wearing – and that's about it. One of the students grabbed her travel bag. Guess what – it contained her draft thesis, written on paper, for heaven's sake! Not even flame-proofed, despite regulations. If we could afford the oxygen, we'd burn it to get some heat.”

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 – perhaps someone will work out that as well. Whatever the answer, I'm afraid it will be too optimistic.” 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 airlock 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”?

Crisis-management was a skill which Morgan admired but did not envy. Janos Bartok, the Tower Safety Officer up at Midway, was now in charge of the situation; those inside the mountain twenty-five thousand kilometres below – and a mere six hundred from the scene of the accident – could only listen to the reports, give helpful advice, and satisfy the curiosity of the news media as best they could.

Needless to say, Maxine Duval had been in touch within minutes of the disaster, and as usual her questions were very much to the point.

“Can Midway Station reach them in time?”

Morgan hesitated; the answer to that was undoubtedly “No”. Yet it was unwise, not to say cruel, to abandon hope as early as this. And there had been one stroke of good luck…

"I don't want to raise false hopes, but we may not need Midway. There's a crew working much closer, at the 10K – ten-thousand-kilometre – Station. Their transporter can reach the Basement in twenty hours.'

“Then why isn't it on the way down?”

“Safety Officer Bartok will be making the decision shortly – but it could be a waste of effort. We think they have air for only half that time. And the temperature problem is even more serious.”

“What do you mean?”

“It's night up there, and they have no source of heat. Don't put this out yet, Maxine, but it may be a race between freezing and anoxia.”

There was a pause for several seconds; then Maxine Duval said in an uncharacteristically diffident tone of voice: “Perhaps I'm being stupid, but surely the weather stations with their big infrared lasers -”

“Thank you, Maxine – I'm the one who's being stupid. Just a minute while I speak to Midway…”

Bartok was polite enough when Morgan called, but his brisk reply made his opinion of meddling amateurs abundantly clear.

“Sorry I bothered you,” apologised Morgan, and switched back to Maxine. “Sometimes the expert does know his job,” he told her with rueful pride. “Our man knows his. He called Monsoon Control ten minutes ago. They're computing the beam power now – they don't want to overdo it, of course, and burn everybody up.” “So I was right,” said Maxine sweetly. “You should have thought of that, Van. What else have you forgotten?”

No answer was possible, nor did Morgan attempt one. He could see Maxine's computer-mind racing ahead, and guessed what her next question would be. He was right.

“Can't you use the Spiders?”

“Even the final models are altitude-limited – their batteries can only take them up to three hundred kilometres. They were designed to inspect the Tower, when it had already entered the atmosphere.”

“Well, put in bigger batteries.”

“In a couple of hours? But that's not the problem. The only unit under test at the moment can't carry passengers.”

“You could send it up empty.”

“Sorry – we've thought of that. There must be an operator aboard to manage the docking, when the Spider comes up to the Basement. And it would still take days to get out seven people, one at a time.”

“Surely you have some plan !”

“Several, but they're all crazy. If any make sense, I'll let you know. Meanwhile, there's something you can do for us.”

“What's that?” Maxine asked suspiciously.

“Explain to your audience just why spacecraft can dock with each other six hundred kilometres up – but not with the Tower. By the time you've done that, we may have some news for you.”

As Maxine's slightly indignant image faded from the screen, and Morgan turned back once more to the well-orchestrated chaos of the Operations Room, he tried to let his mind roam as freely as possible over every aspect of the problem. Despite the polite rebuff of the Safety Officer, efficiently doing his duty up on Midway, he might be able to think of some useful ideas. Although he did not imagine that there would be any magical solution, he understood the Tower better than any living man – with the possible exception of Warren Kingsley. Warren probably knew more of the fine details; but Morgan had the clearer overall picture.

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 to safety, before they were poisoned by CO2, or the pressure dropped so low that the chamber became, in literal truth, a tomb like Mahomet's – suspended between Heaven and Earth.

45. 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 kilometres; Spider's internal battery will take it the rest of the way.”

“And how much payload will that give?”

Kingsley's smile faded.

“Marginal. 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.”

“What does Bartok think?”

“He approves. After all, no one has any better ideas.”

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 hold-ups, 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…”

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 not trying to pull rank on you, Bartok,” said Morgan. “It's a simple matter of logic. True, anyone can drive Spider – but only half-a-dozen men know all the technical details involved. There may be some operational problems when we reach the Tower, and I'm in the best position to solve them.”

“May I remind you, Dr. Morgan,” said the Safety Officer, “that you are sixty-five. It would be wiser to send a younger man.”

“I'm not sixty-five; I'm sixty-six. And age has absolutely nothing to do with it. There's no danger, and certainly no requirement for physical strength.”

And, he might have added, the psychological factors were far more important than the physical ones. Almost anybody could ride passively up and down in a capsule, as Maxine Duval had done and millions of others would be doing in the years ahead. It would be quite another matter to face some of the situations that could easily arise, six hundred kilometres up in the empty sky.

“I still think,” said Safety Officer Bartok with gentle persistence, “that it would be best to send a younger man. Dr. Kingsley, for example.”

Behind him, Morgan heard (or had he imagined?) his colleague's suddenly indrawn breath. For years they had joked over the fact that Warren had such an aversion to heights that he never inspected the structures he designed. His fear fell short of genuine acrophobia, and he could overcome it when absolutely necessary; he had, after all, joined Morgan in stepping from Africa to Europe. But that was the only time that anyone had ever seen him drunk in public, and he was not seen at all for twenty-four hours afterwards.

Warren was out of the question, even though Morgan knew that he would be prepared to go. There were times when technical ability and sheer courage were not enough; no man could fight against fears that had been implanted in him at his birth, or during his earliest childhood.

Fortunately, there was no need to explain this to the Safety Officer. There was a simpler and equally valid reason why Warren should not go. Only a very few times in his life had Vannevar Morgan been glad of his small size; this was one of them.

“I'm fifteen kilos lighter than Kingsley,” he told Bartok. “In a marginal operation like this, that should settle the matter. So let's not waste any more precious time in argument.”

He felt a slight twinge of conscience, knowing that this was unfair. Bartok was only doing his job, very efficiently, and it would be another hour before the capsule was ready. No one was wasting any time.

For long seconds the two men stared into each other's eyes as if the twenty-five thousand kilometres between them did not exist. If there was a direct trial of strength, the situation could be messy. Bartok was nominally in charge of all safety operations, and could theoretically over-rule even the Chief Engineer and Project Manager. But he might find it difficult to enforce his authority; both Morgan and Spider were far below him on Sri Kanda, and possession was nine points of the law.

Bartok shrugged his shoulders, and Morgan relaxed.

“You have a point. I'm still not too happy, but I'll go along with you. Good luck.”

“Thank you,” Morgan answered quietly, as the image faded from the screen. Turning to the still silent Kingsley, he said:

“Let's go.”

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 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? If Safety Officer Bartok had known about this…

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

46. 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 centre was the giant “saucepan lid”, sealing the shaft which would soon carry the traffic of many worlds. Strange to think that the greatest spaceport in the solar system would be deep inside the heart of a mountain.

No one could have guessed that an ancient monastery had once stood here, focusing the hopes and fears of billions for at least three thousand years. The only token that still remained was the ambiguous bequest of the Maha Thero, now crated and waiting to be moved. But, so far, neither the authorities at Yakkagala nor the director of the Ranapura Museum had shown much enthusiasm for Kalidasa's ill-omened bell. The last time it had tolled the peak had been swept by that brief but eventful gale – a wind of change indeed. Now the air was almost motionless, as Morgan and his aides walked slowly to the waiting capsule, glittering beneath the inspection lights. Someone had stencilled the name SPIDER MARK II on the lower part of the housing; and beneath that had been scrawled the promise: WE DELIVER THE GOODS. I hope so, thought Morgan.

Every time he came here 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; the regime that Dr. Sen had prescribed seemed to be working admirably.

Everything had been loaded aboard Spider, which had been jacked up so that the extra battery could be hung beneath it. Mechanics were still making hasty last-minute adjustments and disconnecting power leads; the tangle of cabling underfoot was a mild hazard to a man unused to walking in a spacesuit.

Morgan's Flexisuit had arrived from Gagarin only thirty minutes ago, and for a while he had seriously considered leaving without one. Spider Mark II was a far more sophisticated vehicle than the simple prototype that Maxine Duval had once ridden; 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 airlock on the bottom of the Tower, designed years ago for this very purpose. But a suit would provide not only insurance in case of docking problems; it would give him enormously greater freedom of action. Almost form-fitting, the Flexisuit bore very little resemblance to the clumsy armour of the early astronauts, and, even when pressurised, would scarcely restrict his movements. He had once seen a demonstration by its manufacturers of some spacesuited acrobatics, culminating in a sword-fight and a ballet. The last was hilarious – but it had proved the designer's claims.

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. Although the Mark II was certainly a one-man vehicle, it was not as claustrophobic as he had feared – even with the extra equipment that had been packed into it.

The two oxygen cylinders had been stowed under the seat, and the CO2 masks were in a small box behind the ladder that led up to the overhead airlock. 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 of a talisman; it was still one of the most effective ways of demonstrating the properties of hyperfilament, and whenever he left it behind he almost invariably found that he needed it. On this, of all trips, it might well prove useful.

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

Brilliant speeches were seldom forthcoming at such moments – and this, after all, was going to be a perfectly straightforward operation. Morgan grinned rather stiffly at Kingsley and said: “Mind the store, Warren, until I get back.” Then he noticed the small, lonely figure in the crowd around the capsule. My God, he thought to himself – I'd almost forgotten the poor kid. . . “Dev,” he called. “Sorry I haven't been able to look after you. I'll make up for it when I get back.”

And I will, he told himself. When the Tower was finished there would be time for everything – even the human relations he had so badly neglected. Dev would be worth watching; a boy who knew when to keep out of the way showed unusual promise.

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. Nevertheless, with his usual engineer's caution, Morgan observed that oxygen stood at 102 percent, main battery power at 101 percent, booster battery at 105 percent. ..

The quiet, calm voice of the controller – the same unflappable expert who had watched over all operations since that first abortive lowering years ago – 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 zeroes, then switched on power at the lowest setting.

Smoothly – si1ently -– the flood-lit mountain top 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 metres a second, said the velocity indicator; in slow, regular steps Morgan increased the power until it read fifty – just under two hundred kilometres an hour. That gave maximum efficiency at Spider's present loading; when the auxiliary battery was dropped off speed could be increased by twenty-five percent 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. If you wanted a running commentary, you should have sent Maxine Duval.”

“She's been calling you for the last hour.”

“Give her my love, and say I'm busy. Maybe when I reach the Tower. . . . What's the latest from there?”

“Temperature's stabilised at twenty – Monsoon Control zaps them with a modest megawattage every ten minutes. But Professor Sessui is furious – complains that it upsets his instruments.”

“What about the air?”

“Not so good. The pressure has definitely dropped, and of course the CO2's building up. But they should be O.K. 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.”

“A very good idea – Bartok's, I suppose.”

“Probably. 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. Yet all did seem to be going as well as could be expected; and there was certainly nothing else that he could do for the next three hours except admire the ever-expanding view.

He was already thirty kilometres 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. Soon he could see the whole island of Taprobane, faintly outlined by the lights of the coastal settlements. Far to the north a dull glowing patch was creeping up over the horizon like the herald of some displaced dawn. It puzzled him for a moment, until he realised that he was looking at one of the great cities of Southern Hindustan.

He was higher now than any aircraft could climb, and what he had already done was unique in the history of transportation. Although Spider and its precursors had made innumerable trips up to twenty kilometres, no one had been allowed to go higher because of the impossibility of rescue. It had not been planned to commence serious operations until the base of the Tower was much closer, and Spider had at least two companions who could spin themselves up and down the other tapes of the system. Morgan pushed aside the thought of what could happen if the drive mechanism jammed; that would doom the refugees in the Basement, as well as himself.

Fifty kilometres; 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 metres 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 centimetres across – running along the tape just below me. It's keeping at 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 St. Elmo's Fire. We've had similar displays along the tape during thunderstorms; they can make your hair stand on end aboard the Mark I. But you won't feel anything – you're too well shielded.”

“I'd no idea it could happen at this altitude.”

“Neither did we. You'd better take it up with the Professor.”

“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 towards 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; now he could see it directly, for it extended halfway down the sky. A cage of light, with flickering, moving bars, was descending upon the earth; and now Morgan could understand how a man like Professor Sessui could devote his life to unravelling its secrets.

On one of its rare visits to the equator, the aurora had come marching down from the Poles.

47. Beyond the Aurora

Morgan doubted if even Professor Sessui, five hundred kilometres above, had so spectacular a view. The storm was developing rapidly; short-wave radio – still used for many non-essential 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 pale green 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 before the gusts of the solar wind, the million-kilometre-an-hour 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.

Two hundred kilometres; 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 now rising between the walls of a canyon of fire.

The illusion lasted only for seconds; then the momentary unstable balance between magnetic fields and incoming electric clouds was destroyed. But for that brief instant Morgan could truly believe that he was ascending out of a chasm that would dwarf even Valles Marineris – the Grand Canyon of Mars. Then the shining cliffs, at least a hundred kilometres high, became translucent and were pierced by stars. He could see them for what they really were – mere phantoms of fluorescence.

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. Some of the greens and blues flickering below him now matched the plankton-generated colours he had seen then, and he could easily imagine that he was again watching the byproducts of life – the play of giant, invisible beasts, denizens of the upper atmosphere. . .

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

“How's power holding up?” asked Kingsley “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 five percent. I'm doing 220 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 in a seat and wearing several kilos of spacesuit. Yet Morgan felt positively buoyant, and he wondered if he was getting too much oxygen.

No, the flow-rate was normal. It must be the sheer exhilaration produced by that marvellous spectacle beneath him – though it was diminishing now, drawing back to north and south, as if retreating to its polar strongholds. That, and the satisfaction of a task well begun, using a technology that no man had ever before tested to such limits.

This explanation was perfectly reasonable, but he was not satisfied with it. It did not wholly account for his sense of happiness – even of joy. Warren Kingsley, who was fond of diving, had often told him that he felt such an emotion in the weightless environment of the sea. Morgan had never shared it, but now he knew what it must be like. He seemed to have left all his cares down there on the planet hidden below the fading loops and traceries of the aurora.

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 was yet in sight. But he could make out only the first few metres, still lit by the faint auroral glow, of the narrow ribbon up which Spider was swiftly and smoothly climbing. That thin band upon which his own life – and seven others' – now depended was so uniform and featureless that it gave no hint of the capsule's speed; Morgan found it difficult to believe that it was flashing through the drive mechanism at more than two hundred kilometres an hour. And, with that thought, he was suddenly back in his childhood, and knew the source of his contentment.

He had quickly recovered from the loss of that first kite, and had graduated to larger and more elaborate models. Then, just before he had discovered Meccano and abandoned kites forever, he had experimented briefly with toy parachutes. Morgan liked to think that he had invented the idea himself, though he might well have come across it somewhere in his reading or viewing. The technique was so simple that generations of boys must have rediscovered it.

First he had whittled a thin strip of wood about five centimetres long, and fastened a couple of paper-clips on to it. Then he had hooked these around the kite-string, so that the little device could slide easily up and down. Next he had made a handkerchief-sized parachute of rice paper, with silk strings; a small square of cardboard served as payload. When he had fastened that square to the wooden strip by a rubber band – not too firmly – he was in business.

Blown by the wind, the little parachute would go sailing up the string, climbing the graceful catenary to the kite. Then Morgan would give a sharp tug, and the cardboard weight would slip out of the rubber band. The parachute would float away into the sky, while the wood-and-wire rider came swiftly back to his hand, in readiness for the next launch.

With what envy he had watched his flimsy creations drift effortlessly out to sea! Most of them fell back into the water before they had travelled even one kilometre, but sometimes a little parachute would still be bravely maintaining altitude when it vanished from sight. He liked to imagine that these lucky voyagers reached the enchanted islands of the Pacific; but though he had written his name and address on the cardboard squares he never received any reply.

Morgan could not help smiling at these long-forgotten memories, yet they explained so much. The dreams of childhood had been far surpassed by the reality of adult life; he had earned the right to his contentment.

“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 kilometres, it will have done its job. How do you feel?”

Morgan was tempted to answer with superlatives, but his natural caution dissuaded him. “I'm fine,” he said. “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 this was no cause for alarm; Spider had reached 385 kilometres out of the expected 400, and the booster battery still had some life in it.

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

“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, like one of Morgan's kite-riders. And though a parachute had been available, it was feared that the shrouds might become entangled with the tape. Fortunately the impact area, just ten kilometres east of the earth terminus, lay in dense jungle. The wild life of Taprobane would have to take its chances, and Morgan was prepared to argue with the Department of Conservation later.

He 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 two hundred klicks; it was doing less than one hundred, even at full power. No tests or calculations were necessary; Morgan's diagnosis was instant, for the figures spoke for themselves. Sick with frustration, he reported back to Earth.

“We're in trouble,” he said. “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 several hundred kilos of dead-weight.

48. Night at the Villa

Ambassador Rajasinghe needed little sleep these nights; it was as if a benevolent Nature was granting him the maximum use of his remaining years. And at a time like this, when the Taprobanean skies were blazing with their greatest wonder for centuries, who could have stayed abed?

How he wished that Paul Sarath was here to share the spectacle! He missed his old friend more than he would have thought possible; there was no-one who could annoy and stimulate him in the way that Paul had done – no-one with the same bond of shared experience stretching back to boyhood. Rajasinghe had never thought that he would outlive Paul, or would see the fantastic billion-ton stalactite of the Tower almost span the gulf between its orbital foundation and Taprobane, thirty-six thousand kilometres below. To the end Paul had been utterly opposed to the project; he had called it a Sword of Damocles, and had never ceased to predict its eventual plunge to earth. Yet even Paul had admitted that the Tower had already produced some benefits.

For perhaps the first time in history, the rest of the world actually knew that Taprobane existed, and was discovering its ancient culture. Yakkagala, with its brooding presence and its sinister legends, had attracted special attention; as a result, Paul had been able to get support for some of his cherished projects. The enigmatic personality of Yakkagala's creator had already given rise to numerous books and videodramas, and the son-et-lumiиre display at the foot of the Rock was invariably sold out. Shortly before his death Paul had remarked wryly that a minor Kalidasa industry was in the making, and it was becoming more and more difficult to distinguish fiction from reality.

Soon after midnight, when it was obvious that the auroral display had passed its climax, Rajasinghe had been carried back into his bedroom. As he always did when he had said goodnight to his household staff, he relaxed with a glass of hot toddy and switched on the late news summary. The only item that really interested him was the progress that Morgan was making; by this time he should be approaching the base of the Tower.

The news editor had already starred the latest development; a line of continuously flashing type announced

MORGAN STUCK 200 KM SHORT OF GOAL

Rajasinghe's fingertips requested the details, and he was relieved to find that his first fears were groundless. Morgan was not stuck; he was unable to complete the journey. He could return to earth whenever he wished – but if he did Professor Sessui and his colleagues would certainly be doomed.

Directly above his head the silent drama was being played out at this very moment. Rajasinghe switched from text to video, but there was nothing new – indeed, the item now being screened in the news recap was Maxine Duval's ascent, years ago, in Spider's precursor.

“I can do better than that,” muttered Rajasinghe, and switched to his beloved telescope.

For the first months after he had become bed-ridden he had been unable to use it. Then Morgan had paid one of his brief courtesy calls, analysed the situation, and swiftly prescribed the remedy. A week later, to Rajasinghe's surprise and pleasure, a small team of technicians had arrived at the Villa Yakkagala, and had modified the instrument for remote operation. Now he could lie comfortably in bed, and still explore the starry skies and the looming face of the Rock. He was deeply grateful to Morgan for the gesture; it had shown a side of the engineer's personality he had not suspected.

He was not sure what he could see, in the darkness of the night – but he knew exactly where to look, for he had long been watching the slow descent of the Tower. When the sun was at the correct angle, he could even glimpse the four guiding tapes converging into the zenith, a quartet of shining hair-lines scratched upon the sky.

He set the azimuth bearing on the telescope control, and swung the instrument around until it pointed above Sri Kanda. As he began to track slowly upwards, looking for any sign of the capsule, he wondered what the Maha Thero was thinking about this latest development. Though Rajasinghe had not spoken to the prelate – now well into his nineties – since the Order had moved to Lhasa, he gathered that the Potala had not provided the hoped-for accommodation. The huge palace was slowly falling into decay while the Dalai Lama's executors haggled with the Chinese Federal Government over the cost of maintenance. According to Rajasinghe's latest information, the Maha Thero was now negotiating with the Vatican – also in chronic financial difficulties, but at least still master of its own house.

All things were indeed impermanent, but it was not easy to discern any cyclic pattern. Perhaps the mathematical genius of Parakarma-Goldberg might be able to do so; the last time Rajasinghe had seen him, he was receiving a major scientific award for his contributions to meteorology. Rajasinghe would never have recognised him; he was clean-shaven and wearing a suit cut in the very latest neo-Napoleonic fashion. But now, it seemed, he had switched religions again. . . . The stars slid slowly down the big monitor screen at the end of the bed, as the telescope tilted up towards the Tower. But there was no sign of the capsule, though Rajasinghe was sure that it must now be in the field of view.

He was about to switch back to the regular news channel when, like an erupting nova, a star flashed out near the lower edge of the picture. For a moment Rajasinghe wondered if the capsule had exploded; then he saw that it was shining with a perfectly steady light. He centred the image and zoomed to maximum power.

Long ago he had seen a two-century-old video-documentary of the first aerial wars, and he suddenly remembered a sequence showing a night attack upon London. An enemy bomber had been caught in a cone of searchlights, and had hung like an incandescent mote in the sky. He was seeing the same phenomenon now, on a hundredfold greater scale; but this time all the resources on the ground were combined to help, not to destroy, the determined invader of the night.

49. A Bumpy Ride

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

“We're trying to stop that 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…. Such things happened with monotonous regularity; sometimes they were merely annoying, sometimes they were disastrous, and the man responsible had to carry the guilt for the rest of his days. In any event, 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 infra-red 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 forty thousand kilometres. 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 metre beneath his feet. The end that he could see was secured to the base of Spider by a large butterfly nut; all be had to do was to unscrew that, and the battery would drop off.

Morgan sat silently analysing 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 here four hundred kilometres 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.

Morgan was tempted to retort: “Are you after my job?” but then thought better of it. Warren would be amused; other unknown listeners might not.

After the third fall – he felt he had dropped kilometres, but it was only about a hundred metres – 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 centimetres in front of my nose. I'm going outside to get at it.”

50. The Falling Fireflies

01 15 24

This is Friendship Seven. I'll try to describe what I'm in here. I am in a big mass of some very small particles that are brilliantly lit up like they're luminescent. . . . They're coming by the capsule, and they look like little stars. A whole shower of them coming by.

01 16 10

They're very slow; they're not going away from me more than maybe three or four miles an hour. .

01 19 38

Sunrise has just come up behind in the periscope, as I looked back out of the window, I had literally thousands of small, luminous particles swirling round the capsule.

(Commander John Glenn, Mercury “Friendship Seven”, 1962 Feb. 20.)

With the old-style spacesuits, 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, depressurise 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 spacegloves – against the average small wrench.

He was just about to describe his plan of operations in case anyone on the ground could find a fatal flaw when he became aware of a certain mild discomfort. He could readily tolerate it for much longer, if necessary, but there was no point in taking chances. If he used the capsule's own plumbing, he would not have to bother with the awkward Diver's Friend incorporated in the suit.

When he had finished he turned the key of the Urine Dump – and was startled by a tiny explosion near the base of the capsule. Almost instantly, to his astonishment, a cloud of twinkling stars winked into existence, as if a microscopic galaxy had been suddenly created. Morgan had the illusion that, just for a fraction of a second, it hovered motionless outside the capsule; then it started to fall straight down, as swiftly as any stone dropped on earth. Within seconds it had dwindled to a point, and then was gone.

Nothing could have brought home more clearly the fact that he was still wholly a captive of the earth's gravitational field. He remembered how, in the very early days of orbital flight, the first astronauts were puzzled and then amused by the haloes of ice crystals that accompanied them around the planet; there had been some feeble jokes about the “Constellation Urion”. That could not happen here; anything that he dropped, however fragile it might be, would crash straight back into the atmosphere. He must never forget that, despite his altitude, he was not an astronaut, revelling in the freedom of weightlessness. He was a man inside a building four hundred kilometres high, preparing to open the window and go out on to the ledge.

51. On the Porch

Though it was cold and uncomfortable on the summit, the crowd continued to grow. There was something hypnotic about that brilliant little star in the zenith, upon which the thoughts of the world, as well as the laser beam from Kinte, were now focused. As they arrived, all the visitors would head for the north tape, and stroke it in a shy, half-defiant manner as if to say: “I know this is silly, but makes me feel I'm in contact with Morgan”. Then they would gather round the coffee dispenser and listen to the reports coming over the speaker system. There was nothing new from the refugees in the Tower; they were all sleeping – or trying to sleep – in an attempt to conserve oxygen. As Morgan was not yet overdue, they had not been informed of the hold-up; but within the next hour they would undoubtedly be calling Midway to find what had happened.

Maxine Duval had arrived at Sri Kanda just ten minutes too late to see Morgan. There was a time when such a near-miss would have made her very angry; now she merely shrugged her shoulders and reassured herself with the thought that she would be the first to grab the engineer on his return. Kingsley had not allowed her to speak to him, and she had accepted even this ruling with good grace. Yes, she was growing old. ..

For the last 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 thirty 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 head-room.

"Just getting the feel of the suit – quite flexible – now I'm going out on 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 five minutes and would descend ten kilometres to the east, looked genuinely alarmed.

Only Warren Kingsley failed to share the rejoicing. “Don't cheer too soon,” he said to Maxine. “We're not out of the woods yet.”

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 weight of the battery 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 turn-around 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 last 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 megawatt-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.

52. 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,” be said. “Leave me alone for a few minutes.”

He picked up the fibre 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 metre 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 realised how much he had come to regard it as a talisman – almost a good luck charm. Of course, he did not really believe in such things; he always had a perfectly logical reason for carrying the spinnerette around with him. On this ascent it had occurred to him that it might be useful because of its strength and unique lifting power. He had almost forgotten that it had other abilities as well. ..

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 centimetres 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 metre of coated fibre, 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 round the grille until he could grab the swinging weight. This was not as easy as he had expected, because even this remarkable spacesuit would not allow his arm to bend quite freely, and the ring eluded his grasps 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 fibre around the shank of the bolt, just behind the strap it was still holding in place. Now for the really tricky part.

He released just enough filament from the spinnerette for the naked fibre 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 tempered steel more than a centimetre 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 badly, and could not tell if he had made any progress at all. He was afraid to slacken the tension, lest the fibre should 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.

“Van,” said Kingsley, “just what are you up to? The people in the, Tower have been calling – what shall I say to them?”

“Give me another few minutes – I'm trying to cut the bolt -”

The calm but authoritative woman's voice that interrupted Morgan gave him such a shock that he almost let go of the precious fibre. 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. Back and forth, back and forth he worked the filament, as he crouched over the grille and the four-hundred-kilometre distant earth. He could feel considerable resistance, so he must be making some progress through that stubborn steel. But just how much there was no way of telling.

“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 spacesuit. 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. And he was also sure that – like one of his bridges – she had a built-in safety factor. Her diagnosis would be pessimistic; his condition would not be as serious as she was pretending. Or so he devoutly hoped.

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 fibre. He would keep going, he told himself grimly, just as long as was necessary.

The warning he had relied upon never came. 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 realised that it was clamped around the hinges of the open door. Yet still he did not pull himself back into the cabin; he was hypnotised 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 got 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 Co to expect me in just over an hour. And thank Kinte for the light – I don't need it now.”

He repressurised 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 realised 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.

53. Fade Out

The fact that he was still only thirty 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. Up there in the Tower, now much less than two hundred kilometres away, the reception committee would be preparing to welcome him. He refused even to consider the possibility of any further problems.

When he passed the five-hundred-kilometre mark, still going strong, there was a message of congratulations 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 five-fifty kilometres. By now the rate of ascent should have been over two hundred klicks; it was only one nine eight. Slight though the discrepancy was – and it would make no appreciable difference to his arrival time – it worried Morgan.

When he was only thirty kilometres 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 kilometres to go – a mere fifteen 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 optimise 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 towards the zenith.

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

Just twenty kilometres 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, bearing presents like some troglodytic Father Christmas. Despite his determination to relax, and obey CORA's orders, it was quite impossible to do so. He found himself tensing his muscles, as if by his own physical exertions he could help Spider along the last fraction of its journey.

At ten kilometres there was a distinct change of pitch from the drive motor; Morgan had been expecting this, and reacted to it at once. Without waiting for advice from the ground, he cut speed back to fifty klicks. At this rate he still had twelve minutes to go, and he began to wonder despairingly if he was involved in an asymptotic approach. This was a variant of the race between Achilles and the tortoise; if he halved his speed every time he halved the distance, would he reach the Tower in a finite time? Once he would have known the answer instantly; now he felt too tired to work it out.

At five kilometres 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 airlock towards which he was now crawling with such agonising slowness.

And then it no longer mattered. Two kilometres short of the goal Spider's motors stalled completely. The capsule even slid downwards a few metres, 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 kilometres.”

It was one of the longest ten minutes that Morgan had ever known. Though he could have made it pass more swiftly by responding to Maxine Duval's increasingly desperate pleas, he felt too emotionally exhausted to talk. He was genuinely sorry about this, and hoped that Maxine would understand and forgive him.

He did have one brief exchange with Driver-Pilot Chang, who reported that the refugees in the Basement were still in fairly good shape, and much encouraged by his nearness. They were taking turns to peer at him through the one small porthole of the airlock's outer door, and simply could not believe that he might never be able to bridge the trifling space between them.

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 kilometre 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 be had not exerted himself physically; it only felt that way.

In his preoccupation with Spider he had been neglecting himself. For the last 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 metres to go. ..

He was whistling in the dark, of course. How many aircraft had crashed at the very edge of the runway, after safely crossing an ocean? How many times had machines or muscles failed, when there were only millimetres to go? Every possible piece of luck, bad as well as good, happened to somebody, somewhere. He had no right to expect any special treatment.

The capsule heaved itself upwards 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 twenty metres above him.

54. 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 had possessed a spacesuit, someone could have lowered a rope to him – but there had been no time to collect a suit from the burning transporter.

Of course, if this was a videodrama, and not a real-life problem, some heroic volunteer could sacrifice himself – better still, herself – by going into the lock and tossing down a rope, using the fifteen 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 commonsense 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 had elapsed. Then Warren Kingsley asked a question which, 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, in the sort of tone one uses to address a small child or a difficult invalid. “It makes all the difference in the world. Did you say twenty metres?”

“Yes – that's about it.”

Incredibly – unmistakeably – 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 metres 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 adaptors sometimes failed to latch together properly, because of minute errors in manufacturing tolerances. And, of course, there had never been a chance of testing 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. And until this very moment the now dominant factor in the situation had been so unimportant that it could be completely ignored.

It was all a matter of Relativity. He could not reach the Tower; but the Tower would reach him – at its inexorable two kilometres a day.

55. Hard Dock

The record for one day's construction had been thirty kilometres, 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 kilometres. That was quite fast enough; it would give Morgan time to check the adaptor 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 fifteen minutes – time enough, Morgan hoped, to pacify CORA. Towards 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 of the sky descended upon him. One second the base of the Tower was still metres away; an instant later 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 was not airtight. . . . Morgan tried to interpret the medley of sounds reaching his ears, but he was not skilled enough to read their messages.

Then, like a signal of victory, the DOCKING COMPLETED sign flashed on the indicator board. There would be ten seconds while the telescopic elements could still absorb the movement of the advancing Tower; Morgan used half of them before he cautiously released the brakes. He was prepared to jam them on again instantly if Spider started to drop – but the sensors were telling the truth. Tower and capsule were now firmly mated together. Morgan had only to climb a few rungs of ladder, and he would have reached his goal.

After he had reported to the jubilant listeners on Earth and Midway, he sat for a moment recovering his breath. Strange to think that this was his second visit, but he could remember little of that first one, twelve years ago and thirty-six thousand kilometres away. During what had, for want of a better term, been called the foundation laying, there had been a small party in the Basement, and numerous zero-gee toasts had been squirted. For this was not only the very first section of the Tower to be built; it would also be the first to make contact with Earth, at the end of its long descent from orbit. Some kind of ceremony therefore seemed in order, and Morgan now recalled that even his old enemy, Senator Collins, had been gracious enough to attend and to wish him luck with a barbed but good-humoured speech. There was even better cause for celebration now.

Already Morgan could hear a faint tattoo of welcoming raps from the far side of the airlock. He undid his safety belt, climbed awkwardly on to the seat, and started to ascend the ladder. The overhead hatch gave a token resistance, as if the powers marshalled against him were making one last feeble gesture, and air hissed briefly while pressure was equalised. Then the circular plate swung open and downwards, and eager hands helped him up into the Tower. As Morgan took his first breath of the fetid air he wondered how anyone could have survived here; if his mission had been aborted, he felt quite certain that a second attempt would have been too late.

The bare, bleak cell was lit only by the solar-fluorescent panels which 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 dishevelled 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 labelled 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 be saw masked shapes hovering over him. For a moment he wondered if he was 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 CO2 but allow oxygen to pass. Simple yet technologically sophisticated, they would enable men to survive in an atmosphere which would otherwise cause instant suffocation. It required a little extra effort to breathe through them, but Nature never gives 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? He did not wish to raise the subject, but he wondered.

“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, in the kind of psychological infinite regress that occurs when a group of people share completely a secret which nobody will ever mention again.

He took a few deep breaths – it was amazing how quickly one got used to the masks – and then sat down on the proffered seat. I'm not going to faint again, he told himself with grim determination. I must deliver the goods, and get out of here as quickly as possible – hopefully, before there are any more pronouncements from CORA.

“That can of sealant,” he said, pointing to the smallest of the containers he had brought, “should take care of your leak. Spray it round the gasket of the airlock; it sets hard in a few seconds. Use the oxygen only when you have to; you may need it to sleep. There's a CO2 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. Sessui's people could now take care of themselves, but he still had one further job to do – and the sooner the better.

Morgan turned to Driver Chang and said quietly: “Please help me to suit up again. I want to inspect the track.”

“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.”

Morgan gave a tired smile. Chang was right, and the excuse of immediate danger no longer applied. But an emergency was whatever the Chief Engineer said it was.

“I want to look at the damage,” he answered, “and examine the tracks. It would be a pity if the people from 10K can'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.

Just before he closed the visor Morgan asked, “Any more trouble with the Professor?”

Chang shook his head. “I think the CO2 has slowed him down. And if he starts up again – well, we outnumber him six to one, though I'm not sure if we can count on his students. Some of them are just as crazy as he is; look at that girl who spends all her time scribbling in the corner. She's convinced that the sun's going out, or blowing up – I'm not sure which – and wants to warn the world before she dies. Much good that would do. I'd prefer not to know.”

Though Morgan could not help smiling, he felt quite sure that none of the professor's students would be crazy. Eccentric, perhaps – but also brilliant; they would not be working with Sessui otherwise. One day he must find out more about the men and women whose lives he had saved; but that would have to wait until they had all returned to earth, by their separate ways.

“I'm going to take a quick walk around the Tower,” said Morgan, “and I'll describe any damage so that 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 Chang's reply, as he closed the inner door of the airlock, was very practical and very brief. “How the hell could I?” he asked.

56. View from the Balcony

The outer door of the north airlock opened without difficulty, framing a rectangle of complete darkness. Running horizontally across that darkness was a line of fire – the protective hand-rail 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 metres wide; beyond it the safety net had been stretched out for another thirty metres. 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 that stretched above him like a roadway to the stars – which, 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 electro-chemical one. The twin grooves of the track, now awaiting their first arrival, stretched endlessly upwards in their pristine perfection. And fifty metres below the balcony – though it was hard to look in that direction because of the glare – he could just make out the terminal buffers, ready for a task which they should never have to perform.

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

He felt a curious mixture of elation and fear, such as he had not known since he had learned to swim and found himself for the first time, in water out of his depth. Although he was certain that there was no real danger, there could be. He was acutely aware of CORA, biding her time; but Morgan bad always hated to leave any job undone, and his mission was not yet complete.

The west face was exactly like the north one, except for the absence of an airlock. Again, 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 into 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 guard rail that still remained.

There was a good deal of debris stuck in the track, and the face of the Tower had been discoloured 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.

“Don't worry,” said Morgan. “I've still got ten minutes and all of thirty metres to go. I could manage on the air I have in my lungs now.”

But he did not intend to put it to the test. He had already had quite enough excitement for one night. More than enough, if CORA was to be believed; from now on he would obey her orders implicitly.

When he had walked back to the open door of the airlock he stood for a few final moments beside the guard-rail, 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 upwards towards the stars. That shadow must stretch for thousands of kilometres, 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 a week. That was not a sensible alternative, since he could be back on Sri Kanda in less than three hours.

Time to go inside – his air must be getting low and there was nothing more to see. That was a disappointing irony, considering the spectacular view one would normally have here, by day or by night. Now, however, the planet below and the heavens above were both banished by the blinding glare from Sri Kanda; he was floating in a tiny universe of light, surrounded by utter darkness on every side. It was almost impossible to believe that he was in space, if only because of his sense of weight. He felt as secure as if he were standing on the mountain itself, instead of six hundred kilometres above it. That was a thought to savour, and to carry back to earth.

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

“See you on earth in a year's time,” Morgan whispered, and slowly closed the airlock door behind him.

57. 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 still 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 downwards, becoming weightless for several seconds.

When the speed indicator reached three hundred klicks, the automatic 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 aurora 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, poised forever above Hindustan – and only a few hundred kilometres from the Tower complex. Halfway down in the east was Confucius, much lower still 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 kilometres in extent, or linked by cables which 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 some day, 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 hundred years, perhaps he need not have disturbed the Maha 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 disc so brilliantly that Morgan could see much of the nightland 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 two hundred kilometers – less than an hour to go. There was no point in trying to keep awake; Spider had automatic 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 recognise 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 recognised 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 trajectory 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 ME PLEASE COME AT ONCE!

THIS IS A CORA EMERGENCY!

HELP! WILL ANYONE WHO HEARS ME PLEASE COME AT ONCE!

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

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.

58. Epilogue: Kalidasa's Triumph

In the last days of that last brief summer, before the jaws of ice clenched shut around the equator, one of the Starholme envoys came to Yakkagala.

A Master of the Swarms, It had recently conjugated Itself into human form. Apart from one minor detail, the likeness was excellent; but the dozen children who had accompanied the Holmer in the autocopter were in a constant state of mild hysteria – the younger ones frequently dissolving into giggles.

“What's so funny?” It had asked in Its perfect Solar. “Or is this a private joke?”

But they would not explain to the Starholmer, whose normal colour vision lay entirely in the infra-red, that the human skin was not a random mosaic of greens and reds and blues. Even when It had threatened to turn into a Tyrannosaurus Rex and eat them all up, they still refused to satisfy Its curiosity. Indeed, they quickly pointed out – to an entity that had crossed scores of light-years and collected knowledge for thirty centuries – that a mass of only a hundred kilogrammes would scarcely make an impressive dinosaur.

The Holmer did not mind; It was patient, and the children of Earth were endlessly fascinating, in both their biology and their psychology. So were the young of all creatures – all, of course, that did have young. Having studied nine such species, the Holmer could now almost imagine what it must be like to grow up, mature, and die. . . almost, but not quite.

Spread out before the dozen humans and one non-human lay the empty land, its once luxuriant fields and forests blasted by the cold breaths from north and south. The graceful coconut palms had long since vanished, and even the gloomy pines that had succeeded them were naked skeletons, their roots destroyed by the spreading permafrost. No life was left upon the surface of the Earth; only in the oceanic abyss, where the planet's internal heat kept the ice at bay, did a few blind, starveling creatures crawl and swim and devour each other.

Yet to a being whose home had circled a faint red star, the sun that blazed down from the cloudless sky still seemed intolerably bright. Though all its warmth had gone, drained away by the sickness that had attacked its core a thousand years ago, its fierce, cold light revealed every detail of the stricken land, and flashed in splendour from the approaching glaciers.

For the children, still revelling in the powers of their awakening minds, the sub-zero temperatures were an exciting challenge. As they danced naked through the snowdrifts, bare feet kicking up clouds of powder-dry, shining crystals, their symbiotes often had to warn them: “Don't over-ride your frost-bite signals!” For they were not yet old enough to replicate new limbs without the help of their elders.

The oldest of the boys was showing off; he had launched a deliberate assault on the cold, announcing proudly that he was a fire-elemental. (The Starholmer noted the term for future research, which would later cause It much perplexity.) All that could be seen of the small exhibitionist was a column of flame and steam, dancing to and fro along the ancient brickwork; the other children pointedly ignored this rather crude display.

To the Starholmer, however, it presented an interesting paradox. Just why had these people retreated to the inner planets, when they could have fought back the cold with the powers that they now possessed – as, indeed, their cousins were doing on Mars? That was a question to which It had still not received a satisfactory answer. It considered again the enigmatic reply It had been given by ARISTOTLE, the entity with which It most easily communicated.

“For everything there is a season,” the global brain had replied. “There is a time to battle against Nature, and a time to obey her. True wisdom lies in making the right choice. When the long winter is over, Man will return to an Earth renewed and refreshed.”

And so, during the past few centuries, the whole terrestrial population had streamed up the equatorial Towers and flowed sunwards towards the young oceans of Venus, the fertile plains of Mercury's Temperate Zone. Five hundred years hence, when the sun had recovered, the exiles would return. Mercury would be abandoned, except for the polar regions; but Venus would be a permanent second home. The quenching of the sun had given the incentive, and the opportunity, for the taming of that hellish world.

Important though they were, these matters concerned the Starholmer only indirectly; Its interest was focused upon more subtle aspects of human culture and society. Every species was unique, with its own surprises, its own idiosyncrasies. This one had introduced the Starholmer to the baffling concept of Negative Information – or, in the local terminology, Humour, Fantasy, Myth.

As it grappled with these strange phenomena, the Starholmer had sometimes said despairingly to Itselves: We shall never understand human beings. On occasion It had been so frustrated that It had feared an involuntary conjugation, with all the risks that entailed. But now It had made real progress; It could still remember Its satisfaction the first time It had made a joke – and the children had all laughed.

Working with children had been the clue, again provided by ARISTOTLE. “There is an old saying; the child is father of the man. Although the biological concept of 'father' is equally alien to us both, in this context the word has a double meaning -”

So here It was, hoping that the children would enable It to understand the adults into which they eventually metamorphosed. Sometimes they told the truth; but even when they were being playful (another difficult concept) and dispensed negative information, the Starholmer could now recognise the signs.

Yet there were times when neither the children, nor the adults, nor even ARISTOTLE knew the truth. There seemed to be a continuous spectrum between absolute fantasy and hard historical facts, with every possible graduation in between. At the one end were such figures as Columbus and Leonardo and Einstein and Lenin and Newton and Washington, whose very voices and images had often been preserved. At the other extreme were Zeus and Alice and King Kong and Gulliver and Siegfried and Merlin, who could not possibly have existed in the real world. But what was one to make of Robin Hood or Tarzan or Christ or Sherlock Holmes or Odysseus or Frankenstein? Allowing for a certain amount of exaggeration, they might well have been actual historic personages.

The Elephant Throne had changed little in three thousand years, but never before had it supported the weight of so alien a visitor. As the Starholmer stared into the south, It compared the half-kilometre-wide column soaring from the mountain peak with the feats of engineering It had seen on other worlds. For such a young race, this was indeed impressive. Though it seemed always on the point of toppling from the sky, it had stood now for fifteen centuries.

Not, of course, in its present form. The first hundred kilometres was now a vertical city-still occupied at some of its widely-spaced levels – through which the sixteen sets of tracks had often carried a million passengers a day. Only two of those tracks were operating now; in a few hours the Starholmer and Its escorts would be racing up that huge, fluted column, on the way back to the Ring City that encircled the globe.

The Holmer everted Its eyes to give telescopic vision, and slowly scanned the zenith. Yes, there it was – hard to see by day, but easy by night when the sunlight streaming past the shadow of Earth still blazed upon it. The thin, shining band that split the sky into two hemispheres was a whole world in itself, where half-a-billion humans had opted for permanent zero-gravity life.

And up there beside Ring City was the starship that had carried the envoy and all the other Companions of the Hive across the interstellar gulfs. Even now it was being readied for departure – not with any sense of urgency, but several years ahead of schedule, in preparation for the next six-hundred-year lap of its journey. That would represent no time at all to the Starholmer, of course, for It would not reconjugate until the end of the voyage, but then It might well face the greatest challenge of Its long career. For the first time a Starprobe had been destroyed – or at least silenced – soon after it had entered a solar system. Perhaps it had at last made contact with the mysterious Hunters of the Dawn, who had left their marks upon so many worlds, so inexplicably close to the Beginning itself. If the Starholmer had been capable of awe, or of fear, It would have known both, as It contemplated its future, six hundred years hence.

But now It was on the snow-dusted summit of Yakkagala, facing mankind's pathway to the stars. It summoned the children to Its side (they always understood when It really wished to be obeyed) and pointed to the mountain in the south.

“You know perfectly well,” It said, with an exasperation that was only partly feigned, “that Earthport One was built two thousand years later than this ruined palace.” The children all nodded in solemn agreement. “Then why,” asked the Starholmer, tracing the line from the zenith down to the summit of the mountain, “why do you call that column – the Tower of Kalidasa?”