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10. The Ultimate Bridge

Paul and Maxine were two of his best and oldest friends, yet until this moment they had never met nor, as far as Rajasinghe knew, even communicated. There was little reason why they should; no-one outside Taprobane had ever heard of Professor Sarath, but the whole Solar System would instantly recognise Maxine Duval, either by sight or by sound.

His two guests were reclining in the library's comfortable lounge chairs, while Rajasinghe sat at the villa's main console. They were all staring at the fourth figure, who was standing motionless.

Too motionless. A visitor from the past, knowing nothing of the everyday electronic miracles of this age, might have decided after a few seconds that he was looking at a superbly detailed wax dummy. However, more careful examination would have revealed two disconcerting facts. The dummy was transparent enough for highlights to be clearly visible through it; and its feet blurred out of focus a few centimetres above the carpet.

Do you recognise this man? Rajasinghe asked.

I've never seen him in my life, Sarath replied instantly. He'd better be important, for you to have dragged me back from Maharamba. We were just about to open the Relic Chamber.

I had to leave my trimaran at the beginning of the Lake Saladin races, said Maxine Duval, her famous contralto voice containing just enough annoyance to put anyone less thick-skinned than Professor Sarath neatly in his place. And I know him, of course. Does he want to build a bridge from Taprobane to Hindustan?

Rajasinghe laughed. No we've had a perfectly serviceable causeway for two centuries. And I'm sorry to have dragged you both here though you, Maxine, have been promising to come for twenty years.

True, she sighed. But I have to spend so much time in my studio that I sometimes forget there's a real world out there, occupied by about five thousand dear friends and fifty million intimate acquaintances.

In which category would you put Dr. Morgan?

I've met him oh, three or four times. We did a special interview when the Bridge was completed. He's a very impressive character.

Coming from Maxine Duval, thought Rajasinghe, that was tribute indeed. For more than thirty years she had been perhaps the most respected member of her exacting profession, and had won every honour that it could offer. The Pulitzer Prize, the Global Times Trophy, the David Frost Award these were merely the tip of the iceberg. And she had only recently returned to active work after two years as Walter Cronkite Professor of Electronic Journalism at Columbia.

All this had mellowed her, though it had not slowed her down. She was no longer the sometimes fiery chauvinist who had once remarked: Since women are better at producing babies, presumably Nature has given men some talent to compensate. But for the moment I can't think of it. However, she had only recently embarrassed a hapless panel chairman with the loud aside: I'm a newswoman, dammit not a newsperson.

Of her femininity there had never been any doubt; she had been married four times, and her choice of REMS was famous. Whatever their sex, Remotes were always young and athletic, so that they could move swiftly despite the encumbrance of up to twenty kilos of communications gear. Maxine Duval's were invariably very male and very handsome; it was an old joke in the trade that all her REMs were also RAMS. The jest was completely without rancour, for even her fiercest professional rivals liked Maxine almost as much as they envied her.

Sorry about the race, said Rajasinghe, but I note that Marlin III won very handily without you. I think you'll admit that this is rather more important But let Morgan speak for himself.

He released the PAUSE button on the projector, and the frozen statue came instantly to life.

My name is Vannevar Morgan. I am Chief Engineer of Terran Construction's Land Division. My last project was the Gibraltar Bridge. Now I want to talk about something incomparably more ambitious.

Rajasinghe glanced round the room. Morgan had hooked them, just as he had expected.

He leaned back in his chair, and waited for the now familiar, yet still almost unbelievable, prospectus to unfold. Odd, he told himself, how quickly one accepted the conventions of the display, and ignored quite large errors of the Tilt and Level controls. Even the fact that Morgan moved while staying in the same place, and the totally false perspective of exterior scenes, failed to destroy the sense of reality.

"The Space Age is almost two hundred years old. For more than half that time, our civilisation has been utterly dependent upon the host of satellites that now orbit Earth. Global communications, weather forecasting and control, land and ocean resources banks, postal and information services if anything happened to their space-borne systems, we would sink back into a dark age. During the resultant chaos, disease and starvation would destroy much of the human race.

"And looking beyond the Earth, now that we have self-sustaining colonies on Mars, Mercury and the Moon, and are mining the incalculable wealth of the asteroids, we see the beginnings of true interplanetary commerce. Though it took a little longer than the optimists predicted, it is now obvious that the conquest of the air was indeed only a modest prelude to the conquest of space.

But now we are faced with a fundamental problem an obstacle that stands in the way of all future progress. Although generations of research have made the rocket the most reliable form of propulsion ever invented -

("Has he considered bicycles?" muttered Sarath.)

" space vehicles are still grossly inefficient. Even worse, their effect on the environment is appalling. Despite all attempts to control approach corridors, the noise of take-off and re-entry disturbs millions of people. Exhaust products dumped in the upper atmosphere have triggered climatic changes, which may have very serious results. Everyone remembers the skin-cancer crisis of the twenties, caused by ultra-violet break-through and the astronomical cost of the chemicals needed to restore the ozonosphere.

"Yet if we project traffic growth to the end of the century, we find that Earth-to-orbit tonnage must be increased almost fifty percent. This cannot be achieved without intolerable costs to our way of life perhaps to our very existence. And there is nothing that the rocket engineers can do; they have almost reached the absolute limits of performance, set by the laws of physics.

What is the alternative? For centuries, men have dreamed of anti-gravity or of 'spacedrives'. No-one has ever found the slightest hint that such things are possible; today we believe that they are only fantasy. And yet, in the very decade that the first satellite was launched, one daring Russian engineer conceived a system that would make the rocket obsolete. It was years before anyone took Yuri Artsutanov seriously. It has taken two centuries for our technology to match his vision.

Each time he played the recording, it seemed to Rajasinghe that Morgan really came alive at this point. It was easy to see why; now he was on his own territory, no longer relaying information from an alien field of expertise. And despite all his reservations and fears, Rajasinghe could not help sharing some of that enthusiasm. It was a quality which, nowadays, seldom impinged upon his life.

"Go out of doors any clear night," continued Morgan, "and you will see that commonplace wonder of our age the stars that never rise or set, but are fixed motionless in the sky. We and our parents and their parents have long taken for granted the synchronous satellites and space stations, which move above the equator at the same speed as the turning earth, and so hang forever above the same spot.

"The question Artsutanov asked himself had the childlike brilliance of true genius. A merely clever man could never have thought of it or would have dismissed it instantly as absurd.

"If the laws of celestial mechanics make it possible for an object to stay fixed in the sky, might it not be possible to lower a cable down to the surface and so to establish an elevator system linking Earth to space?

"There was nothing wrong with the theory, but the practical problems were enormous. Calculations showed that no existing materials would be strong enough; the finest steel would snap under its own weight long before it could span the thirty-six thousand kilometres between Earth and synchronous orbit.

"However, even the best steels were nowhere near the theoretical limits of strength. On a microscopic scale, materials had been created in the laboratory with far greater breaking strength. If they could be mass-produced, Artsutanov's dream could become reality, and the economics of space transportation would be utterly transformed.

"Before the end of the twentieth century, super-strength materials hyperfilaments had begun to emerge from the laboratory. But they were extremely expensive, costing many times their weight in gold. Millions of tons would be needed to build a system that could carry all Earth's outbound traffic; so the dream remained a dream.

Until a few months ago. Now the deep-space factories can manufacture virtually unlimited quantities of hyperfilament. At last we can build the Space Elevator or the Orbital Tower, as I prefer to call it. For in a sense it is a tower, rising clear through the atmosphere, and far, far beyond

Morgan faded out, like a ghost that had been suddenly exorcised. He was replaced by a football-sized Earth, slowly revolving. Moving an arm's-breadth above it, and keeping always poised above the same spot on the equator, a flashing star marked the location of a synchronous satellite.

From the star, two thin lines of light started to extend-one directly down towards the earth, the other in exactly the opposite direction, out into space.

When you build a bridge, continued Morgan's disembodied voice, you start from the two ends and meet in the middle. With the orbital tower, it's the exact opposite. You have to build upwards and downwards simultaneously from the synchronous satellite, according to a careful programme. The trick is to keep the structure's centre of gravity always balanced at the stationary point; if you don't, it will move into the wrong orbit, and start drifting slowly round the earth.

The descending line of light reached the equator; at the same moment, the outward extension also ceased.

"The total height must be at least forty thousand kilometres and the lowest hundred, going down through the atmosphere, may be the most critical part, for there the tower may be subject to hurricanes. It won't be stable until it's securely anchored to the ground.

And then, for the first time in history, we shall have a stairway to heaven a bridge to the stars. A simple elevator system, driven by cheap electricity, will replace the noisy and expensive rocket, which will then be used only for its proper job of deep-space transport. Here's one possible design for the orbital tower -

The image of the turning earth vanished as the camera swooped down towards the tower, and passed through the walls to reveal the structure's cross-section.

"You'll see that it consists of four identical tubes two for Up traffic, two for Down. Think of it as a four-track vertical subway or railroad, from Earth to synchronous orbit.

"Capsules for passengers, freight, fuel would ride up and down the tubes at several thousand kilometres an hour. Fusion power stations at intervals would provide all the energy needed; as ninety percent of it would be recovered, the net cost per passenger would be only a few dollars. For as the capsules fall earthwards again, their motors will act as magnetic brakes, generating electricity. Unlike re-entering spacecraft, they won't waste all their energy heating up the atmosphere and making sonic booms; it will be pumped back into the system. You could say that the Down trains will power the Up ones; so even at the most conservative estimate, the elevator will be a hundred times more efficient than any rocket.

And there's virtually no limit to the traffic it could handle, for additional tubes could be added as required. If the time ever comes when a million people a day wish to visit Earth or to leave it the orbital tower could cope with them. After all, the subways of our great cities once did as much

Rajasinghe touched a button, silencing Morgan in mid-sentence.

The rest is rather technical he goes on to explain how the tower can act as a cosmic sling, and send payloads whipping off to the moon and planets without the use of any rocket power at all. But I think you've seen enough to get the general idea.

My mind is suitably boggled, said Professor Sarath. But what on earth or off it has all this to do with me? Or with you, for that matter?

Everything in due time, Paul. Any comments, Maxine?

Perhaps I may yet forgive you; this could be one of the stories of the decade or the century. But why the hurry not to mention the secrecy?

There's a lot going on that I don't understand, which is where you can help me. I suspect that Morgan's fighting a battle on several fronts; he's planning an announcement in the very near future, but doesn't want to act until he's quite sure of his ground. He gave me that presentation on the understanding that it wouldn't be sent over public circuits. That's why I had to ask you here.

Does he know about this meeting?

Of course; indeed, he was quite happy when I said I wanted to talk to you, Maxine. Obviously, he trusts you and would like you as an ally. And as for you, Paul, I assured him that you could keep a secret for up to six days without apoplexy.

Only if there's a very good reason for it.

I begin to see light, said Maxine Duval. Several things have been puzzling me, and now they're starting to make sense. First of all, this is a space project; Morgan is Chief Engineer, Land.


Yhu should ask, Johan! Think of the bureaucratic in-fighting, when the rocket designers and the aerospace industry get to hear about this! Trillion dollar empires will be at stake, just to start with. If he's not very careful, Morgan will be told 'Thank you very much now we'll take over. Nice knowing you.'

I can appreciate that, but he has a very good case. After all, the Orbital Tower is a building not a vehicle.

Not when the lawyers get hold of it, it won't be. There aren't many buildings whose upper floors are moving at ten kilometres a second, or whatever it is, faster than the basement.

You may have a point. Incidentally, when I showed signs of vertigo at the idea of a tower going a good part of the way to the moon, Dr. Morgan said, 'Then don't think of it as a tower going up think of it as a bridge going out'. I'm still trying, without much success.

Oh! said Maxine Duval suddenly. That's another piece of your jig-saw puzzle. The Bridge.

What do you mean?

Did you know that Terran Construction's Chairman, that pompous ass Senator Collins, wanted to get the Gibraltar Bridge named after him?

I didn't; that explains several things. But I rather like Collins the few times we've met, I found him very pleasant, and very bright. Didn't he do some first-rate geothermal engineering in his time?

That was a thousand years ago. And you aren't any threat to his reputation; he can be nice to you.

How was the Bridge saved from its fate?

There was a small palace revolution among Terran's senior engineering staff. Dr. Morgan, of course, was in no way involved.

So that's why he's keeping his cards close to his chest! I'm beginning to admire him more and more. But now he's come up against an obstacle he doesn't know how to handle. He only discovered it a few days ago, and it's stopped him dead in his tracks.

Let me go on guessing, said Maxine. It's good practice helps me to keep ahead of the pack. I can see why he's here. The earth-end of the system has to be on the equator, otherwise it can't be vertical. It would be like that tower they used to have in Pisa, before it fell over.

I don't see said Professor Sarath, waving his arms vaguely up and down. Oh, of course His voice trailed away into a thoughtful silence.

Now, continued Maxine, there are only a limited number of possible sites on the equator it's mostly ocean, isn't it? and Taprobane's obviously one of them. Though I don't see what particular advantages it has over Africa or South America. Or is Morgan covering all his bets?

As usual, my dear Maxine, your powers of deduction are phenomenal. You're on the right line but you won't get any further. Though Morgan's done his best to explain the problem to me, I don't pretend to understand all the scientific details. Anyway, it turns out that Africa and South America are not suitable for the space elevator. It's something to do with unstable points in the earth's gravitational field. Only Taprobane will do worse still, only one spot in Taprobane. And that, Paul, is where you come into the picture.

Mamada? yelped Professor Sarath, indignantly reverting to Taprobani in his surprise.

Yes, you. To his great annoyance, Dr. Morgan has just discovered that the one site he must have is already occupied to put it mildly. He wants my advice on dislodging your good friend Buddy.

Now it was Maxine's turn to be baffled. Who? she queried.

Sarath answered at once. The Venerable Anandatissa Bodhidharma Mahanayake Thero, incumbent of the Sri Kanda temple, he intoned, almost as if chanting a litany. So that's what it's all about.

There was silence for a moment; then a look of pure mischievous delight appeared on the face of Paul Sarath, Emeritus Professor of Archaeology of the University of Taprobane.

I've always wanted, he said dreamily, to know exactly what would happen when an irresistible force meets an immovable object.

9. Filament | The Fountains of Paradise | 11. The Silent Princess