The Foundations of Paradise - Arthur C. Clarke [81]
43
Fail-Safe
Five kilometers from the terminus, Driver-Pilot Rupert Chang had reduced speed 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. Upward, it was true, the twin grooves along which they were riding still stretched forever—or at least for twenty-five thousand kilometers, which on the human scale was much the same. But downward, 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 again. Chang studied them with a frown of annoyance and pressed the RESET button. They flickered once, then vanished.
The first time this happened, two hundred kilometers higher, there had been a hasty consultation with Midway Control. A quick check of all systems had revealed nothing amiss; indeed, if all the warnings were to be believed, the transporter’s passengers were already dead. Everything had gone outside the limits of tolerance.
It was obviously a fault in the alarm circuits themselves, and Professor Sessui’s explanation was accepted with general relief. The vehicle was no longer in the pure vacuum environment for which it had been designed. The ionospheric turmoil it had now entered must be 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 instrument readings. 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 kilometers higher, and if they couldn’t climb back to that they would be in trouble. But he 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 end of the braking process, they should have been glowing a dull red. Chang would have been very worried had he known that they were still comfortably cool. Energy can never be destroyed; it has to go somewhere. And often it goes to the wrong place.
When the FIRE—BATTERY COMPARTMENT sign came on for the third time, Chang did not hesitate to reset it. A real fire, he knew, would have triggered the extinguishers. In fact, one of his biggest worries was that these might operate unnecessarily.
There were several anomalies on the board now, especially in the battery-charging circuits. As soon as the journey was over and he’d powered down the transporter, Chang was going to climb into the motor room and give everything a good old-fashioned eyeball inspection.
As it happened, his nose alerted him first, when there was barely more than a kilometer to go. Even as he stared incredulously at the thin wisp of smoke oozing out of the control board, the coldly analytical part of his mind was saying, “What a lucky coincidence that it waited until the end of the trip!”
Then he remembered all the energy being produced during the final braking, and had a pretty shrewd guess at the sequence of events. The protective circuits must have failed to operate, and the batteries had been overcharging. One fail-safe after another had let them down. Helped by the ionospheric storm, the sheer perversity of inanimate things struck again.
Chang punched the battery-compartment fire-extinguisher button. At least that worked, because he could hear the muffled roar of the nitrogen blasts on the other side