LITMIR.BIZ

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leaked into space. So, the system as a whole possessed vast hierarchies of check valves, crossover switches, and redundancies that had saturated even Ivy’s brain, normally an infinite sink for detail. She’d had to delegate all cooling-related matters to a working group that was about three-quarters Russian and one-quarter American. The majority of all space walk activity was related to the expansion and maintenance of the cooling system and, uncharacteristically for her, she was content just to get a report on it once a day.

      All of that plumbing, and all of those radiators, needed to be supported by Izzy’s structure just like anything else—they were especially prone to troubles under the general heading of “too floppy to survive reboost.” So, proceeding in the same general putting-out-fires mode, Ivy and the engineers on the ground next had to steer the program in the general direction of “consol,” or, as Ivy put it privately, “defloppification,” of the space station’s overall structure. And since it was out of the question to take apart what the Scouts and Pioneers had put in place, this took the form of building what amounted to external scaffolding around what was there. Viewed from a kilometer away, it looked quite similar to what one saw when some old and treasured building was being renovated: a latticework of structure, ugly but serviceable, grew around the underlying object, enveloping it and strengthening it without actually penetrating it.

      In the early going, sections of truss were assembled on the ground, launched up whole, and slammed into place by teams of spacewalkers, buying large increases in structural integrity quickly and expensively. That approach soon fell prey to the law of diminishing returns and it became clear that the Arkers, as they’d started to be known, couldn’t be forever dependent on ground-based engineers custom-building structures.

      The ground-based engineers didn’t even really know what was going on with Izzy anymore. Their CAD models had fallen behind. Dinah knew it because of a sudden surge in messages from exasperated engineers requesting that she send a robot out to such-and-such a place and aim its camera at such-and-such a module so that they could see what was actually there.

      The Arkers needed tools and materials for building their own structures in situ. These started to arrive around Day 220. And it was a measure of how much things had changed on the ground that the solutions came in more than one form, from more than one source, often with little to no coordination. In the old days a proposed system would have been given a three-letter acronym and bounced back and forth between different agencies and contractors for fifteen years before being launched into space.

      The single most useful structure-building system turned out to be a rough-and-ready implementation of an old but good idea. It was a little bit like the machine used by gutter and downspout contractors, mounted in the back of a truck, fed by a large roll of sheet metal, which would be bent into a gutter shape and extruded in pieces as long as you liked. This machine did much the same thing, except that it bent the sheet metal ribbon into a simple beam with a triangular cross section and then welded the edges together to make it permanent. It had been invented and prototyped long ago in the West, but the Chinese space agency had perfected it in the first couple of hundred days post-Zero and begun to launch the machines up with crews who knew how to use them. As long as they were supplied with electricity and rolls of aluminum they would go on pumping out beams forever. Connecting segments of beam into more complex structures, such as trusses and scaffolding, was a little more difficult. Welding in space, while possible, was complicated, and there wasn’t enough equipment. Instead they ended up using Tinkertoy-like connectors, again mass-produced by the Chinese, into which the ends of the triangular beams could be inserted, then tightened down using screws. At first many of these were shipped up in bulk from the ground, but on A+0.247 they took delivery of a 3-D printer that had been optimized to make more of them, with options for modifying the angle at which the beams would be inserted. This gave them the ability to design and build trusses on the fly, which was not possible with the mass-produced connectors. And as a last resort, Fyodor had an electron-beam welding machine that would work in zero gravity and a vacuum, undoubtedly the most expensive welder ever made, a marvel of Russian ingenuity, and he had trained Vyacheslav to use it. Vyacheslav then trained Tekla and two of the other spacewalkers, who set up a job queue and took turns drifting around Izzy’s increasingly complex structure tacking down a weld here and a weld there. Thus, constructed largely by the Chinese and the Russians, the scaffolding grew and stiffened. The reboost burns no longer produced alarming pops, bangs, and groaning noises. The hamster tubes gradually disappeared within shrouds of structural reinforcement and shielding. New docking ports began to sprout at Izzy’s extremities, like buds on tree branches, in preparation for the next phase: the coming of the first arklets.

      Down on the Earth, it was August, the second-to-the-last August that there would ever be. A dozen new or reconditioned spaceports had come into operation. Heavy-lift rockets could now be launched to Izzy from eight different locations around the world. Around those launch pads, rocket stages and three different styles of arklet were beginning to pile up like so much ammunition at a firing range.

       DAY 260

      “You’re going, Dr. Harris,” said Julia Bliss Flaherty.

      From time to time Doob became distracted by the sheer oddity of the fact that he now met with the president on a regular basis. It was a lot less weird, in the big scheme of things, than the fact that the moon had exploded and that everyone was going to die. But his mind, born and raised in a world free of such prodigies, was more comfortable being freaked out by little things, such as talking to the president. In the Oval Office. With her science advisor Pete Starling on one side and the White House communications director on the other. And a butler pouring ice water into crystal tumblers.

      He saw the usefulness of the butler. But what was the point of having the communications director here? Margaret Sloane was good at her job, and the perfection of her grooming was a perpetual source of wonderment, but it had become pretty clear that she was out of her depth in any technical discussion beyond “big rocks from space are dangerous.”

      They were all looking at him as if he was expected to say something.

      What had been the president’s words? You’re going.

      Did that mean he was on his way out? Going to be replaced by someone younger and more web-savvy, like Tav Prowse?

      Into the awkward silence, Margaret Sloane poured an explanation. “Your skills and your presence have done so much to calm the waters. To give the people of the United States, and of Earth, something to pin their hopes on in the guiding concept of Our Heritage. Your willingness to roll up your sleeves, go to places like Moses Lake, Baikonur, the rocket factories—that has all been so appreciated. But we feel that the time has come—”

      “To replace me with a fresh face, I get it,” Doob said. “To tell you the truth, that’s fine. I would like to spend more time with my kids and my new wife. Tav will do a great job.”

      For once, the president looked flummoxed. Her eyes flicked toward Margaret.

      “That’s not where we were going with it at all,” said Margaret. “We need you—the people of the world need you—to take the next step—to advance to a higher level.”

      “We are asking you,” said the president, a bit testy with Doob’s slowness and with Margaret’s breathy and roundabout phrasings, “to travel into space on or about Day 360, and to become part of the population of the Cloud Ark.”

      “I don’t want to go!” Doob blurted out. It was rare for him to forget himself in that way, so he then just sat for a few moments, stunned by his own ineptitude.

      “Dr. Harris,” said the president after a few moments, “as you probably know from your high school civics class, the person who sits where I’m sitting has a lot of powers. One of them is that I can grant reprieves and pardons for convicted criminals. Every inmate who goes to the execution chamber in Texas goes there in part because I made the decision not to pardon him or to commute his sentence. I have never exercised that power in the case of a death row inmate. In effect, however, I am exercising it in your case now.”

      The

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