Chapter 17 17. The Dancing Bridge

Morgan spends an average of about ten days a month in his office at the "Land" branch on the sixth floor of the Global Construction Association building in Nairobi.The bottom floor is the "Ocean" branch, while the upper floor is the general management office, which is the office of the association's president Collins and his staff.In keeping with the symbolic simplicity, the architect allocated the highest floor to the "Universe" division.On the roof was set up an observatory with a modest telescope; however, this telescope was never used seriously. The favorite target of the "researchers" is the window of the "Samsung" Hotel, which is only one kilometer away from the association building.Through the telescope, we can observe all kinds of extremely special and most secret way of life.

Since Morgan was in constant contact with the two secretaries (one of whom was a robot) while he was away, he could return without worrying about any unexpected news.Even by the standards of a time when robots were not widely used, his division was a modest one.Under Morgan's leadership, there were less than three hundred staff, but thanks to the use of electronic computers, they were able to perform a large number of calculations.Otherwise, even if all the inhabitants of the earth are mobilized, it is impossible to undertake such a huge computational workload. "How's it going?" asked his lieutenant and longtime friend when Morgan and Warren Kingsley were alone.

"Not at all. I can't believe until now that this absurd thing is pulling our legs. What do the jurists say?" Morgan retorted. "Everything depends on the ruling of the international court. If the court thinks that this design is necessary for society, the monks will have to suffer a little bit... otherwise, the situation will be complicated. Perhaps, they will have to give them a small earthquake?" Morgan's membership in the Tectonics Commission was often the stuff of jokes among friends.However, even tectonic scientists have not yet found (for mankind, this should be said to be a kind of luck) a way to control earthquakes.Besides, they never raised such a subject.People have only learned to predict earthquakes reliably, thereby lessening their destructive effects a little.

"I'll seriously consider your suggestion," said Morgan, shrugging. "But what about the main problem?" "See for yourself." The lights in the room went out.Above the carpet hangs a model of the earth covered with a coordinate grid.Above it, at about a person's height, a bright line of the Space Orbital Tower moves.A series of letters and numbers are displayed directly in the air, which indicate speed, acceleration, mass... "The simulation is running five hundred times faster than normal. Now it starts," Warren explained. An invisible force deflects the glowing lines from vertical.The perturbation is spreading upwards, which is the use of electronic computers to simulate the movement of cargo under the action of the earth's gravitational field.

"How much off?" Morgan asked. "About two hundred meters. It's going to be three hundred meters, and before that..." The bright line is broken.The Space Orbit Tower is cut in half, and its two parts are separated by a slow, decelerated motion simulating thousands of kilometers per hour-one part is gradually approaching the earth, while the other part is spinning and flying into space. Deep down...however, the imaginary accident deduced by the computer is overwhelmed by the real scene that has been haunting Morgan's mind for many years. Morgan has watched this two-century-old video at least fifty times, and he has studied some of the clips shot by shot until he memorizes the tiniest details.The film's plot cost the U.S. government record peacetime spending -- millions of dollars for every minute of film.

The unrelenting shot clearly captures a graceful (so graceful!) bridge flying across a canyon, and a lone car stopped halfway by a frightened motorist.No fuss!It's just that a vision that has never been heard of in the entire history of technology happened on the bridge. It is unbelievable that the metal structure weighing thousands of tons turned out to be like this: From the side view, the bridge does not seem to be made of steel but rubber.Long waves up to several meters slowly undulate on the heavy structure, making it look like an angry python.The wind blowing along the canyon, with vibrations inaudible to the human ear, aroused the resonance of the structure.Over the course of a few hours, the oscillations gradually intensified, but no one could have foreseen the results it would lead to, and the end that the hapless designers could have predicted was now drawing closer and closer.

Suddenly, the heavy-duty steel cables snapped under the blows of these deadly whips.The pavement of the bridge collapsed into the deep valley; various decorations on the structure rotated and flew in all directions.Even when the film is running at normal speed, the disaster seems to be unfolding in slow motion; the momentum of the scene is indescribable.In fact, the entire event lasted only five seconds; in such a short time, the bridge across the Tacoma Canyon has since achieved its instructive status in the history of technology.Two centuries later, a photograph of its final moments hangs in Morgan's office with the caption: "One of our worst achievements."

For Morgan, this is not a joke but a motto, and it reminds him at any time that unexpected dangers may lurk everywhere.When they designed the Gibraltar Bridge, he pored over Kalman's classic book on the Tacoma disaster.The lesson was not in vain: even under the most violent hurricanes from the Atlantic, there were never serious problems in terms of vibrations, only the road was shifted by a hundred meters in one case, which was the same design The data are strictly consistent. But designing a space elevator is such a bold leap into the unknown that some unpleasant surprises are almost inevitable.It is not difficult to calculate the wind pressure on the lower part of the elevator track, but the vibration caused by the movement of the cargo and even the vibration caused by the gravitational changes of the sun and moon should also be taken into account.According to the so-called "worst case analysis", all these factors - plus occasional earthquakes, must not only be calculated item by item, but must be considered in combination.

"The results were consistent across all the models for this cargo volume specification," Warren said. "The vibration builds up gradually and then breaks at about 500 kilometers. The mass of the counterweight has to be increased substantially." "That's what worries me. How much more?" Morgan asked. "Ten million tons." Based on his intuitive experience in engineering, Morgan's estimate is also this figure.Now, electronic computers have confirmed it.Ten million tons!Before his eyes appeared the Yakkajala Mountain with the sky of Taborobani as the background.Such a huge cliff needs to be sent 40,000 kilometers into the air: fortunately, this is not strictly necessary, and there are other ways to think about it.

Morgan has always encouraged his staff to use their independent thinking spirit as much as possible. This is the only way to develop a sense of responsibility and reduce the leader's own workload.As a result, his colleagues often came up with solutions that Morgan himself hadn't thought of. "What shall we do, Warren?" "It is possible to use a catapult located on the moon. However, this method is time-consuming and expensive. The soil of the moon must be used and then rebuilt into the required space orbit. In addition, there will be psychological problems. question……"

"I understand that. We shouldn't have a second San Luis Domingo," Morgan said, nodding thoughtfully. This is the name of a small town (thankfully a small town) in South America; a piece of lunar soil destined for a space station near Earth has accidentally landed on this town.Apparently, this was caused by not aiming at the target. In this way, the first artificial crater appeared on the earth.The incident resulted in the tragic death of 250 people.Since then, the inhabitants of the earth have strongly opposed the "cosmic launch". "It would be much easier to use an asteroid with a suitable orbit in space." Warren continued. carbon. In this way, we can 'kill two birds with one stone'." "One stone...seems a little too big, but I like the idea. A catapult on the moon is probably not suitable-otherwise, we can borrow it for a few years. Of course, with this method, it is inevitable Part of the cargo will be lost. If your asteroid’s mass is not large enough, we can use the elevator itself to replenish the missing mass. Of course, it’s best not to consume so much power.” "This approach is probably the most economical." "Really?" Morgan asked.After a minute's pause, he added: "If that's the case, the space engineers will hate me to death." "Hate me almost as much as Santa Balakalma," continued Morgan, muttering to himself. In fact, what he said was not fair.For true religious believers, no feeling of hatred is allowed at all.There, when they were in the temple, the eyes of Jom Godbear meant something else too: to fight unwaveringly to the end. Yes, fight with all available means.