Читать книгу Seveneves - Neal Stephenson - Страница 9

“WE NEED TO STOP ASKING OURSELVES WHAT HAPPENED AND START talking about what is going to happen,” Dr. Harris said to the president of the United States, her science advisor, the chairman of the Joint Chiefs of Staff, and about half of the Cabinet.

He could see that the president didn’t like that. Julia Bliss Flaherty, currently nearing the end of her first year on that job.

The chairman of the JCS was nodding, but President Flaherty was giving him a hard, squinting look, and not just because of the light coming in the window from the skies over Camp David. She thought he was up to something. Trying to shift blame. Trying to push some kind of new agenda. “Go on,” she said. Then, remembering her manners, “Dr. Harris.”

“Four days ago I watched Kidney Bean break in half,” Doob said. “The Seven Sisters became eight. Since then, we’ve seen a near miss that could have fractured Mr. Spinny.”

“I would almost welcome it,” said the president, “if we could get rid of those ridiculous names.”

“It’ll happen,” Doob said. “The question is, how long does Mr. Spinny have to live? And what does that tell us?” He clicked a small remote in his hand and brought up a slide on the big screen. Heads turned toward it and he felt a mild sense of relief at not being stared at anymore by the president. The slide was a montage of a snowball rolling down a hill, a fuzzy bacterial culture growing in a petri dish, a mushroom cloud, and other seemingly unrelated phenomena. “What do these all have in common? They are exponential,” he said. “The word gets tossed around a lot by people who use it to mean anything that’s getting big fast. But it has a specific mathematical meaning. It means any process where the more it happens, the more it happens. The population explosion. A nuclear chain reaction. A snowball rolling down a hill, whose speed of growth is pegged to how much it’s grown.” He clicked through another slide showing plots of exponential curves on a graph, then to an image of the moon’s eight pieces. “When the moon had only one piece, the probability of a collision was zero,” he said.

“Because there was nothing to collide with,” Pete Starling, the president’s science advisor, explained. The president nodded.

“Thank you, Dr. Starling. When you have two pieces, why then, yes, they can collide. The more pieces you get, the higher the chances of any two pieces banging into each other. But what happens when they bang into each other?” He clicked the control again and showed a little movie of Kidney Bean’s breakup. “Well, sometimes, but not always, they break in half. Which means you have more pieces. Eight instead of seven. Nine instead of eight. And that increase in number means an increase in the odds of further collisions.”

“It’s an exponential,” said the chairman.

“It occurred to me four days ago that it did have all the earmarks of an exponential process,” Doob allowed. “And we know what happens to those.”

President Flaherty had been watching him intently but she now flicked her eyes over at Pete Starling, who made a dramatic upward zooming gesture with one hand, tracing the profile of a hockey stick.

“When an exponential hits the bend in the hockey stick curve,” Doob said, “the result can be indistinguishable from a detonation. Or it can look like a slow, steady increase. It all depends on the time constant, the inherent speed with which the exponential thing happens. And on how we perceive it as humans.”

“So it might be nothing,” said the chairman.

“It could be that a hundred years will pass before we go from eight chunks to nine chunks,” Doob said, nodding at him, “but four days ago I got worried that it might be one of those things that looks more like an explosion. So my grad students and I have been crunching some numbers. Building a mathematical model of the process that we can use to get a handle on the time scale.”

“And what are your results, Dr. Harris? I assume you have some, or else you wouldn’t be here.”

“The good news is that the Earth is one day going to have a beautiful system of rings, just like Saturn. The bad news is that it’s going to be messy.”

“In other words,” said Pete Starling, “the chunks of the moon are going to keep banging into each other indefinitely and breaking up into smaller and smaller pieces, spreading out into a system of rings. But some rocks are going to fall on the ground and break things.”

“And can you tell me, Dr. Harris, when this is going to happen? Over what period of time?” the president asked.

“We’re still gathering data, tuning the model’s parameters,” Doob said. “So my estimates could all be off by a factor of two, maybe three. Exponentials are tricky that way. But what it looks like to me is this.”

He clicked through to a new graph: a blue curve showing a slow, steady climb over time. “The time scale at the bottom is something like one to three years. During that time, the number of collisions and the number of new fragments are going to grow steadily.”

“What is BFR?” asked Pete Starling. For the graph’s vertical scale was labeled thus.

“Bolide Fragmentation Rate,” Doob said. “The rate at which new rocks are being produced.”

“Is that a standard term?” Pete wanted to know. His tone was not so much hostile as unnerved.

“No,” Doob said, “I made it up. Yesterday. On the plane.” He was tempted to add something like I am allowed to coin terms but didn’t want things to get snarky this early in the meeting.

Seeing that Pete had been silenced, at least for a moment, Doob tried to get back into his rhythm. “We’ll see an increasing number of meteorite impacts. Some will cause great damage. But overall, life is not going to change that much. But then”—he clicked again, and the plot bent sharply upward, turning white—“we are going to witness an event that I am calling the White Sky. It’ll happen over hours, or days. The system of discrete planetoids that we can see up there now is going to grind itself up into a vast number of much smaller fragments. They are going to turn into a white cloud in the sky, and that cloud is going to spread out.”

Click. The graph continued shooting upward, rocketing up into a new domain and turning red.

“A day or two after the White Sky event will begin a thing I am calling the Hard Rain. Because not all of those rocks are going to stay up there. Some of them are going to fall into the Earth’s atmosphere.”

He turned the projector off. This was an unusual move, but it snapped them all out of PowerPoint hypnosis and forced them to look at him. The aides in the back of the room were still thumbing their phones, but they didn’t matter.

“By ‘some,’” Doob said, “I mean trillions.”

The room remained silent.

“It is going to be a meteorite bombardment such as the Earth has not seen since the primordial age, when the solar system was formed,” Doob said. “Those fiery trails we’ve been seeing in the sky lately, as the meteorites come in and burn up? There will be so many of those that they will merge into a dome of fire that will set aflame anything that can see it. The entire surface of the Earth is going to be sterilized. Glaciers will boil. The only way to survive is to get away from the atmosphere. Go underground, or go into space.”

“Well, obviously that is very hard news if it is true,” the president said.

They all sat and thought about it silently for a period of time that might have been one minute or five.

“We will have to do both,” the president said. “Go into space, and underground. Obviously the latter is easier.”

“Yes.”

“We can get to work building underground bunkers for …” and she caught herself before saying something impolitic. “For people to take refuge in.”

Doob didn’t say anything.

The chairman of the Joint Chiefs of Staff said, “Dr. Harris, I’m an old logistics guy. I deal in stuff. How much stuff do we need to get underground? How many sacks of potatoes and rolls of toilet paper per occupant? I guess what I’m asking is, just how long is the Hard Rain going to last?”

Doob said, “My best estimate is that it will last somewhere between five thousand and ten thousand years.”

“NONE OF YOU WILL EVER STAND ON TERRA FIRMA, TOUCH YOUR loved ones, or breathe the atmosphere of your mother planet again,” the president said. “That is a terrible fate. And yet it is a better fate than seven billion people trapped on the Earth’s surface can hope for. The last ship home has sailed. From now on, launch vehicles will rise up into orbit, but they will not go back for ten thousand years.”

The twelve men and women in the Banana sat in silence. Like the destruction of the moon itself, it was too big a thing for them to take in, too large for human emotion to get around. Dinah focused on trivia. Such as: just how damned good J.B.F.—the president—was at saying stuff like this.

“Dr. Harris,” said Konrad Barth, the astronomer. “I am sorry, Madam President, but is it possible to get Dr. Harris back into the picture?”

“Of course,” said Julia Bliss Flaherty, who, with some reluctance, stepped sideways, making room for the larger frame of Dr. Harris. Dinah thought that he looked shrunken and diminished compared to the famous TV scientist. Then she remembered what he had explained to them a few minutes ago, and felt uncharitable for having drawn that comparison. What must it have been like, to be the only man on Earth to know that the Earth was doomed?

“Yes, Konrad,” he said.

“Doob, I’m not disagreeing with your calculations. But has this been peer reviewed? Is there a chance that there is some basic error, a misplaced decimal point, something?”

Harris had begun nodding his head halfway through Konrad’s question. It was not a happy kind of nod. “Konrad,” he said, “it’s not just me.”

“We have signals intelligence suggesting that the Chinese figured it out a day before we did,” the president said, “and the British, the Indians, the French, Germans, Russians, Japanese—all of their scientists are coming to more or less the same conclusions.”

“Two years?” Dinah piped up. Her voice was hoarse, broken. Everyone looked at her. “Until the White Sky?”

“People seem to be converging on that figure, yeah,” Dr. Harris said. “Twenty-five months, plus or minus two.”

“I know that this is a terrible shock for all of you,” said the president. “But I wanted the crew of the ISS to be among the first to know about it. Because I need you. We, the people of the United States and of Earth, need you.”

“For what?” Dinah asked. In no sense was she the official spokesman for Izzy’s crew of twelve. That was Ivy’s job. But Dinah could tell, just from looking at her, that Ivy was in no condition to speak.

“We are beginning to talk to our counterparts in other spacefaring nations about creating an ark,” the president said. “A repository of the entire genetic heritage of the Earth. We have two years to build it. Two years to get as many people and as much equipment as we can into orbit. The nucleus of that ark is going to be Izzy.”

Absurdly, Dinah felt a mild flicker of annoyance that J.B.F. had appropriated their informal term for the ISS. But she knew how it was. She had spent enough time with the NASA PR people to understand. Things had to be humanized, to be given cute names. All the terrified kids down there who knew they were going to die would have to watch upbeat videos about how Izzy was going to carry the legacy of the dead planet through the Hard Rain. They would take out their crayons and draw cartoon pictures of Izzy with a torus halo and a big rock on her ass and a little anthropomorphic smiley face on the side of the Zvezda Service Module.

Ivy spoke up for the first time in a while. A mere two weeks ago, the postponement of her wedding had seemed a big disappointment. But she had just been told that her fiancé—U.S. Navy commander Cal Blankenship—was a dead man walking and that she would never marry him, never touch him, never see him again except through a video link. To say nothing of everyone else she knew. She looked a little spacey. She was talking in her singsongy voice. “Madam President,” she said, “I’m sure you know that there isn’t much space up here to accommodate new people. I’m sure this must be a topic of discussion.”

“Yes, of course,” the president said. “Your job is to—”

“Pardon me, Madam President, can I take this?” Dr. Harris asked. Dinah noted the flick of the president’s eyes, the look of shock on her face. The president of the United States had just been interrupted. Shouldered out of the way. As a woman who had made her way up in the world, she probably had some raw nerve endings around that sort of thing.

But this wasn’t that. It wasn’t J.B.F. asking herself did he interrupt me because I’m a woman? They were past all of that now. This was her asking herself did he interrupt me because the president of the United States doesn’t matter anymore?

“Is Lina there?” Dr. Harris asked. “Pan the camera around please—ah, there you are. Lina, I have read your articles about the swarming behaviors of fish in the Caribbean. Great stuff.”

“I didn’t know your interests extended to things underwater,” said Lina Ferreira. “Thank you.”

People were funny, Dinah thought. Talking like this, at a time like this.

“The videos are amazing. They all move in tight formation, until a predator comes through. Then, suddenly, a hole just opens up in the swarm and the predator sails through it and doesn’t catch a single fish. A moment later they’re back together again. Well, nothing’s been decided yet, but—”

“You want to use swarming behavior in the ark?”

“The proposal is called the Cloud Ark,” the president cut back in. “And you have it correct. Rather than putting all our eggs in one basket—”

“Eggs … and sperm,” Jibran muttered, in his Lancashire accent, so low that only Dinah picked it up.

“We will take a distributed architecture,” J.B.F. said, with perhaps too careful enunciation, as if she had learned the phrase ten minutes ago. “Each of the ships that will make up the Cloud Ark will be autonomous to an extent. We will mass-produce them, I am told, and send them up just as fast as we can. They will swarm around Izzy. When it is safe to do so, they can dock together, like Tinkertoys, and people can move from one to the other freely. But when a rock approaches, fwoosh!” And she spread her fingers apart, the purple lacquered nails darting away from one another.

But what about Izzy? Dinah wondered. She thought better of asking just now.

“In order to make ready for that, there are tasks for all of you,” the president said. “And that is why I asked the director to join us on this call.” Meaning Scott Spalding, the director of NASA. “I’m going to turn it over to Sparky, so that he can walk you through the details. As you can imagine, I have some other concerns to look after, and so I am going to bid you goodbye at this point.”

The twelve in the Banana mustered a low murmur of thanks to usher the president out of whatever conference room this transmission was coming from. Someone torqued the camera around until it was pointing at Scott Spalding. He had managed to find a blazer but he was tieless, and probably would be for the remainder of his life. As a young astronaut, Sparky had been slated for an Apollo mission that had been canceled during the budget cutbacks of the early 1970s. He had stuck with the program, getting his Ph.D. during the hiatus in manned spaceflight that followed. His run of bad luck had continued when a planned mission on Skylab was scrubbed because of the spacecraft’s untimely descent into the atmosphere. His perseverance had paid off in the 1980s with a series of Shuttle missions that had turned him into a past master of the astronaut corps, equally at home fixing busted solar panels and quoting the poetry of Rainer Maria Rilke. After a couple of decades working at tech startups with varying levels of success, he’d been brought back to NASA a few years ago as part of some dimly conceived repurposing of the agency’s mission. Most of the people in the Banana found him likable, if somewhat opaque, and had the general feeling that he would back them up in a pinch.

Exactly what Rilke poems Sparky thought could address the world’s current predicament, it was impossible to guess. For a moment there, after the camera swung around to autofocus on his sagging and creased face, it almost seemed like some poetry might be on the tip of his tongue. Then he shook it off and found the camera’s lens with his pale eyes. “Words fail me,” he said, “so I am just going to concentrate on business. Ivy, you remain in charge. There’s no one better. Your job is to keep things running up there, communicate with us down here, let us know what you need. If after all of that you find yourself with some free time, let me know and I’ll find you a hobby.” He winked.

And from there he went down the list.

Frank Casper, a Canadian electrical engineer, and Spencer Grindstaff, an American who specialized in communications and who had been doing mysterious work for intelligence agencies, were going to work on establishing the network infrastructure needed to support the activities of the Cloud Ark. Jibran, an instrumentation specialist who was always getting roped into such problems anyway, would work with them.

Fyodor Panteleimon, their grizzled space walk specialist, and Zeke Petersen, a more boyish-looking American air force pilot who also had many hours of experience in space suits, would begin preparing for the arrival of new modules that, they were assured, were being designed and built with un-NASA-like haste and would begin arriving at Izzy in less than a month. Dinah found that time estimate to be ludicrously optimistic until she remembered that essentially all the world’s resources were being thrown at this.

Konrad Barth was simply asked to stay on after the meeting for a talk with Doob. It was obvious enough that he would soon be repurposing every astronomical gadget on the space station to the problem of looking for incoming rocks. This was a topic no one wanted to dwell on. If Izzy got hit by a rock of any size, it was all over. In that sense there really was no point in talking about it.

The life scientists were Lina Ferreira; Margaret Coghlan, an Australian woman studying the effects of spaceflight on the human body; and Jun Ueda, a Japanese biophysicist running some lab experiments about the effects of cosmic rays on living tissues. Also in that general category was Marco Aldebrandi, an Italian engineer who focused on the more practical matter of running the life support systems that kept the rest of them alive. Of those four, Lina already had a special status in that she had actually done work on swarming. It wasn’t that closely related to what she had been doing on the space station, but now she was going to have to dust it off and make it her life’s work. Sparky gave her carte blanche to hole up in a quiet place and cram her brain with papers on that topic for a little while, getting back up to speed. Margaret and Jun were told to put their more abstract research work out the airlock and work under Marco on readying Izzy for a large expansion in population.

That covered eleven of the twelve. So far, Sparky hadn’t said a word to Dinah.

Meetings had never been her strong suit. She felt like she was playing an away game whenever she sat down in a conference room. Her awareness of this got in the way and turned into a self-fulfilling prophecy. It had always been thus. The fact that the world was ending changed nothing. As Sparky kept ticking down the list, telling each person what they would be doing in the coming weeks, she kept feeling more and more the point of focus precisely because she hadn’t been focused on yet. And when it became clear that she was last on Sparky’s list, she had a good long while, as he talked to Margaret and Jun and Marco, to wonder what that meant. Being Dinah, her first assumption was that she was considered so important that she was being saved for last. But by the time Sparky finally spoke her name, she had arrived at a different guess as to what was happening. Her heart was already thumping and her pinkies tingling, her tongue bulky in her mouth.

“Dinah,” Sparky said, “you’re indispensable.”

She knew exactly what this meant, in meeting-speak: they would put her out the airlock if they could.

“You have such a wide range of capabilities and we all admire your attitude so much.”

Sparky hadn’t said a word to anyone else about their attitude.

“Obviously, asteroid mining—which you’ve devoted so much of your career to—is a project with a long-term payoff. But we are in short-term mode now.”

“Of course.”

“I am detailing you to assist Ivy and look for ways that you can put your amazing skill set to use in supporting the activities of the others. Fyodor and Zeke can only go on so many space walks. Maybe your robots can be put to use doing things that they can’t.”

“As long as it involves cutting through iron, they’ll be awesome,” Dinah said.

“Sounds great,” Sparky said, missing the sarcasm entirely. In his own mind he was finished with the conversation, tolerating a few moments’ small talk before the after-meeting with Doob and Konrad.

Dinah thought better of herself than this. How could she let herself get into this frame of mind at such a time?

Because maybe there was actually a good reason for how she was feeling.

She was halfway through saying goodbye to Sparky when she pivoted back. “Hang on a sec,” she said. “I respect what you said about short-term mode. I get that. But if, or when, this Cloud Ark thing works, you know what’s next, right?”

Sparky was in no mood. Not so much annoyed with her as bewildered. “What’s next?”

“People need a place to live. And if the surface of the Earth is going to be burned off, we’re going to have to make those living places up here, out of stuff we can get our hands on. Asteroids. Of which we have a lot more now, thanks to the Agent.”

Sparky put his hands over his face, exhaled, and sat motionless for about a minute. When he took his hands away, she could see he’d been weeping. “I wrote half a dozen goodbye letters to old friends and family before this meeting,” he said, “and when it’s over I’m going to keep working my way down the list. Maybe I’ll write half of all the letters I want before their intended recipients get killed by the Hard Rain. The point being, I guess, that I am thinking like the dead man walking that I truly am. Which is wrong. I should be thinking about what you are thinking about. The future that you and a few others may look forward to if all of this other stuff works.”

“You really think we’re looking forward to it?”

Sparky winced. “Not in the sense of thinking that that future’s going to be great but in the sense of at least thinking about it. I don’t disagree with you. But what do you want me to do now?”

“Watch my back,” Dinah said. “Don’t let them ditch Amalthea. Don’t let them cut up all of my robots for spare parts. You want me to work on other stuff for a while, fine. But when the sky turns white and the Hard Rain begins to fall, the Cloud Ark needs to have a viable program for making things out of asteroids or else there is no way people are going to stay alive up here for thousands of years.”

“I have your back, Dinah,” said Sparky, “for what that is worth.” And his eyes strayed in the direction of the door through which the president had exited.

AT A+0, THE TWELVE-PERSON CREW OF THE INTERNATIONAL SPACE Station had included only a single Russian: Lieutenant Colonel Fyodor Antonovich Panteleimon, a fifty-five-year-old veteran of six missions and eighteen space walks, the éminence grise of the cosmonaut corps. This was unusual. In the early years, out of the ISS’s usual crew of six, at least two had normally been cosmonauts. The addition of Project Amalthea and of the torus had expanded the station’s maximum capacity to fourteen, and the number of Russians had typically varied between two and five.

The moon had disintegrated only two weeks before Ivy, Konrad, and Lina had been scheduled to return home, to be replaced by two more Russians and a British engineer.

Since that rocket and its crew were ready to go anyway, Roskosmos—the Russian space agency—went ahead and launched it from the Baikonur cosmodrome on A+0.17.

The Soyuz spacecraft docked at Izzy’s Hub module without incident. Unlike Americans, who liked flying things by hand, the Russians had made docking into an automated process a long time ago.

The Soyuz—the workhorse, for decades, of human space launch—was a stack of three modules. At its aft end was a mechanical section containing engines, propellant tanks, photovoltaic panels, and other equipment that didn’t require an atmosphere. Its forward section was a more or less spherical vessel meant to be pressurized with breathable air, and containing enough empty space for cosmonauts to move around, work, and live. In the middle was a smaller bell-shaped section containing three couches where the space-suited occupants would ride into space and later descend back to Earth cloaked in a fiery comet tail. Accommodations in that section were extremely cramped, but it didn’t matter since it was only used briefly during launch and reentry; the orbital module, which was the larger sphere on the front, was where the cosmonauts spent most of their time. And on its nose was the mating contraption that enabled it to connect with the space station, or any other object suitably equipped.

Until a couple of years ago the Soyuz capsules had usually docked at the aft end of the Zvezda module, which had been the “tail” of the ISS. More recently a new module called the Hub had been attached to the Zvezda, extending the main axis of the space station “rearward,” and providing the axle around which the torus revolved. In order to maintain compatibility with the ubiquitous and time-tested Soyuz, the Hub had been equipped with a suitable port and hatch.

Since the other eleven were busy with the tasks that Sparky had given them, Dinah floated “aft” down the whole length of Izzy—for her shop was attached to its “forward” end—and opened the docking hatch to greet the new arrivals. She was expecting to see a few humans floating free in the orbital module of the newly arrived Soyuz. Instead she saw the head and arm of a single cosmonaut, whom she vaguely recognized as Maxim Koshelev. He was embedded in a nearly solid mass of vitamins.

“Vitamins” was a term of art used by spaceflight geeks to mean any small, lightweight stuff of extraordinary value. Microchips, medicine, spare parts, ukuleles, biological samples, soap, and food all fell under the general heading of “vitamins.” Humans, of course, were the most important vitamin of all, unless you were one of those who believed that all space exploration should be conducted by robots. Dinah had sat in many a conference where her colleagues in the asteroid mining industry had argued passionately that rockets, which were so expensive, should only be used to transport vitamins. Bulk materials such as metals and water should never be launched from the ground; they ought to be obtained from the billions of rocks that were wandering around in space already.

A sealed box of hypodermic syringes tumbled out and caromed off her forehead, followed by a vac-packed bag of lithium hydroxide gravel, a bottle of morphine, a reel of surface-mount capacitors, and a rubber-banded bundle of number two lead pencils, presharpened. Once Dinah had pawed those out of the way she was able to more fully take in the scene: Maxim, jammed in a narrow human-sized tunnel through a mass of vitamins that had been packed into the Soyuz until it couldn’t hold any more.

Someone down in Tyuratam had had the foresight to cram in a few folded-up garbage bags. Taking the hint, Dinah peeled one of them open and used it to corral all the items that had escaped so far and were threatening to go on a random walk around Izzy. Then she began raking out more. Lots of stuff escaped, but most of it went into the bag. Maxim eased himself out into the Hub for a stretch. He’d been crammed into this thing for six hours. Dinah, who was smaller, went into the space he’d vacated and began throwing vitamins out to him; he just held up a garbage bag to catch them.

After a minute she excavated a human thigh in a blue jumpsuit, then a shoulder, then an arm. The arm moved and pushed more vitamins at her, exposing a face that Dinah recognized from having scanned her Wikipedia entry half an hour ago. This was Bolor-Erdene, a woman who had once been rejected from the cosmonaut program because she was too small to fit into any of the standard space suits. She was riding in a couch that had clearly been jury-rigged for the purpose. It was strapped to a part of the orbital module called the Divan with an improvised scheme of cargo webbing that was still dusty from the roads of Kazakhstan. Dinah wondered if it was the last dirt she would ever see, then tried to suppress that thought.

So, both Bolor-Erdene and Maxim had ridden in the orbital module, which was unprecedented; humans were supposed to ride only in the reentry module aft of it.

It would have been indiscreet to point this out, but those two, by riding up front, had signed up for a one-way journey that could have turned into a suicide mission had anything gone wrong. The orbital module was jettisoned during the reentry process, and burned up in the atmosphere. Only the passengers in the reentry module could even theoretically make it back alive.

The vitamin bagging proceeded through the hatch into the reentry module and went viral as faces and arms were freed. In the three couches, where humans were supposed to ride, were the two other scheduled cosmonauts, Yuri and Vyacheslav, and the Brit, who was named Rhys.

Bolor-Erdene, Yuri, and Vyacheslav took their first chance to unstrap and move up through the orbital module into the Hub. Rhys requested that he be given a moment.

Dinah went into the Hub to greet the other four. In normal times these moments were at least a little bit ceremonious, with the new arrivals being greeted with hugs, or at least high fives, as they glided through the hatch, and photographs taken. The impending deaths of everyone on Earth cast a bit of a pall over this occasion, but Dinah felt she should at least say a few words to each of them.

Bolor-Erdene urged Dinah to address her as Bo. She was obviously of Far Eastern stock, and yet there was something in her eyes and cheekbones that did not look precisely Chinese. Dinah’s preliminary googling had already told her that Bo was Mongolian.

Yuri and Maxim were coming to ISS for their third and fourth times, respectively. Vyacheslav seemed to be a last-minute substitution for a younger cosmonaut who would have been making his first trip to the ISS. Vyacheslav had done two previous stints. So, all the Russians except for Bo were old hands at this, and once they had exchanged brief greetings with Dinah they glided through the middle of the Hub, looking about curiously since some of them hadn’t seen it before, and then through the hatch into the Zvezda module, which was like home to them. They exchanged clipped remarks in Russian of which Dinah understood about 50 percent. Everyone who worked on Izzy had to have at least working knowledge of Russian.

Rhys Aitken was an engineer who had made a career of building strange new constructs, usually for wealthy clients. Until seventeen days ago, his mission had been to lay groundwork for the addition of a second, larger torus, built around a newer Hub aft of the existing one and intended for space tourists. This was part of a public-private partnership between NASA and Rhys’s employer, a British billionaire who had been one of the early movers in the space tourism industry. Rhys had a new mission now, but he was still a perfect fit for the job.

Dinah went back through the orbital module and peered through the hatch at him, lying there patiently motionless in his couch.

“First time in space?” Dinah asked him, though she already knew the answer.

“Don’t you have Google up here?” he responded. From an American it would have been simply obnoxious, but Dinah had spent enough time around Brits to take it as intended.

“You just don’t seem very eager to explore your new home.”

“I’m stretching it out. The process of discovery. Besides, I was warned not to move my head.”

“To avoid nausea. Yeah, that’s good advice,” Dinah said. “But you have to move it eventually.” A loose packet of cucumber seeds, stenciled in Cyrillic, floated past her head. She plucked it carefully out of the air. Finding herself in range, she stuck out her hand. “Dinah,” she said.

“Rhys.” He extended his hand while gazing rigidly ahead, as he’d been instructed. But in the time-honored manner of most human males, he allowed his eyeballs to swivel her way so that he could check her out, then turned his head so that he could check her out better.

“You’re going to regret that,” she said.

“Oh, my goodness,” he exclaimed.

“You have a few minutes before it all comes up. Come on out, I’ll get you a bag.”

DURING ONE OF MANY RECENT SLEEPLESS “NIGHTS,” DINAH HAD found herself worrying about transistors. Modern semiconductor technology had found a way to make them very small. So small that they could be destroyed by a single hit from a cosmic ray. This didn’t much matter down on the ground, because the stakes were lower and cosmic rays were mostly blocked by the atmosphere. But electronics that had to work in space were a different matter. The world’s military-industrial complexes had put a lot of money and brainpower into making “rad-hard” electronics, more resistant to cosmic ray strikes. The resulting chips and circuit boards were, by and large, clunkier than the sleek consumer electronics that earthbound customers had come to expect. A lot more expensive too. So much so that Dinah had avoided using them at all in her robots. She used cheap, tiny off-the-shelf electronics in the expectation that a certain number of her robots would be found dead every week. A functional robot could carry a dead one back to the little airlock between Dinah’s workshop and the pitted surface of Amalthea, and Dinah could swap its fried circuit board out for a new one. Sometimes the new one would already be dead, struck by a cosmic ray while it was just sitting there in storage. But the vitamins shipped up on the ISS supply missions always had more of them.

The only shielding from cosmic rays was matter. A thick atmosphere such as Earth’s would do the trick, or a much thinner bulwark of solid heavy material. Of course, Dinah happened to have one in the form of Amalthea itself. Any object nestled up against Amalthea’s surface would be shielded from cosmic rays coming from roughly half of the universe—the half blocked from view by the asteroid. For the same reason, the ISS was always shielded by the Earth from any cosmic rays approaching from that direction. So there was a sweet spot, on the side of Dinah’s shop that faced toward Earth but was “under” the bulk of Amalthea, where cosmic rays could only squirt in from a relatively narrow band of space. Dinah stored her spare chips and circuit boards in that general area, just to improve their odds, and she limited the amount of time that her robots spent roaming about on the side of Amalthea that faced deep space.

In clear view of her window was a hollow in Amalthea’s side, perhaps an ancient impact crater, big enough to accommodate a watermelon.

On Day 9—five days before the conference in the Banana when Doc Dubois had told them about the Hard Rain and the president had told them that they were never coming home—she had programmed several of her robots—the ones with the most effective cutting heads—to begin making that hollow deeper. Perhaps she’d had a premonition of what was about to happen. Or perhaps she was just doing her job; mining robots would need to have the ability to carry out programmed activities such as boring tunnels into rock, and it was high time she began experimenting with such tasks.

But after that conference in the Banana, she had gone back to her little shop and, as an alternative to crying all night or sticking her head out the airlock, she had altered the program that those little robots were following and told them to begin bending the tunnel, curving it gently as it delved into the asteroid. Until then, the robots had been moving directly away from her and she’d been able to look through her tiny quartz window, into the watermelon-sized hollow, and straight down the tunnel that the robots were cutting. She had to flip a welding glass down over the window when she did this because they were cutting with plasma arcs whose brilliant purple light would burn her eyes. But by the time that the five new arrivals got to Izzy on A+0.17, the robots had disappeared around the bend in the tunnel that they had made. The universe could not see them. Cosmic rays ran in straight lines, like light, and they could not negotiate that bend.

Dinah had them carve a little hollow into the side of that tunnel: a storage niche. She packaged up all of her spare chips and PC boards into a bundle. It was a small one, given how tiny and powerful modern chips were—a cube small enough to hold in one hand. Normally this would have been a bad idea—a single cosmic ray might shoot through the entire stack and kill every board at once. She handed it off to an eight-legged robot and sent that robot through the airlock and down the tunnel. Seeing through the remote eye of its video camera, manipulating a data glove connected to its grappling arms, she maneuvered it into the niche and then made it splay out its arms and go rigid so that it couldn’t drift out. Her transistors were now safe.

Rhys watched her do it. He had been on Izzy for five hours. He was too sick to do anything except lie very still. Dinah, whose shop was full of zip ties and clamps and other useful devices, had helped him wedge his head between a couple of pipes, padding them with foam to make it a little more comfortable. She had left him with a supply of barf bags and gone about her work.

“What do you call that type?” he asked.

“A Grabb,” she answered. “Short for Grabby Crab.”

“Good name, I suppose.”

“It’s the most obvious body type for something that’s meant to pick its way around on a rock. Each leg has an electromagnet on its tip, so it can stick to Amalthea, which is mostly iron. When it wants to pick up that foot, it just switches off the magnet.”

“I’m sure you’ve already thought of this,” Rhys said delicately, “but you could hollow out the whole asteroid this way. Create a shielded environment. Maybe even fill it with air.”

Dinah nodded. She was busy, placing the Grabb’s eight arms one by one, making sure each of them was stuck to a wall of the niche. It would be embarrassing if all of her vitamins floated out and got lost. “We’ve discussed it. Me and the, like, eight thousand engineers on the ground who are working on this.”

“Yes, I didn’t suppose it was a solo effort.”

“The constraint is working gas. The plasma cutters are very powerful, but they require some gas flow. Almost any gas will do. But industrial gases are rare and valuable up here, and they have this annoying habit of escaping into space.”

“But if you were hollowing something out, as opposed to working on its surface—”

“Exactly,” Dinah said. “You could seal the exits and recapture the used gas, and recycle it.”

“So you’re way ahead of me, in other words.”

Dinah’s upper face was obscured in a VR rig but a smile spread below it. “That’s the thing about space,” she said. “So many smart people are so interested in it that it’s difficult to come up with a really new idea.”

There was a pause in the conversation while she switched control to a different robot and got it moving down the tunnel.

“Moving my eyeballs oh so slightly, I see at least three other morphologies in your bestiary.”

“The Siwi is adapted from a robot that was made for exploring collapsed buildings. Which in turn was obviously adapted from a snake.”

“A sidewinder, presumably, given the name.”

“Yeah. The electromagnets are arranged around the Siwi’s body in a double helix, so by turning some on and others off, it can sort of roll diagonally along the surface with minimal power usage.”

“The thing that looks like a Buckyball seems to be using a similar trick.”

“You nailed the name. We do in fact call those Buckies. Technically speaking, it’s a thing called a—”

“Tensegrity.”

Dinah felt herself blushing. “Of course, you’d know all about those. Anyway, because it’s big and roughly spherical, it can roll in any direction by playing tricks with electromagnetics and making its struts get longer or shorter. The brains live in that sort of nucleuslike package suspended in the middle.”

“Grabbs, Siwis, and Buckies. What do you call the tiny ones?”

“Nats. Our attempt to build a swarm. Lina’s been moonlighting on it.”

There was a little gap in the conversation while both of them considered the unfortunate choice of wording.

“It’s pretty experimental still,” Dinah continued. “But the idea is that they can latch on to each other as needed, like ants making an ant-ball to cross a river. I know this must all seem pretty weird. It’s not normal engineering.”

“I’m not a normal engineer. I’ve been doing biomimetics—which is what you are doing—for a while. Except I build things that stand still.”

“Okay. You get it then.” Dinah peeled off the 3-D goggles she’d been using to see through the eyes of the Grabb. The second robot, the Siwi, had perched itself in the tunnel behind the Grabb and raised its head, cobralike, to shine light on it and shoot video. Gazing at the flat-panel screen, Dinah made the Siwi pan back and forth to inspect the Grabb’s position, ensuring there was no way those circuit boards could drift away.

“Yes. I get it,” Rhys said. Then he added, “It’s not for me to tell you your business. But you know what hermit crabs do, don’t you?”

It took Dinah a few moments to access the memory. She had never been a beach kind of person. “They use the discarded shells of other crabs as shelter.”

“Not of other crabs, but of mollusks. But yes, you have it.”

Dinah thought about it for a moment, then turned to look at him. He seemed slightly less green and sweaty than before. “I think I see where you are going.”

“Better yet,” Rhys said, “consider the foraminifera.”

“What are they?”

“The biggest single-celled organisms in the world. They live beneath the Antarctic ice. And as they grow, they take grains of sand from their environment and glue them together to form hard outer skins.”

“Sort of like Ben Grimm?” she asked.

It was a throwaway reference to a comic book character, the armor-plated member of the Fantastic Four. She didn’t expect him to pick up on it. But he shot back: “To name another cosmic ray victim, yes. But without the alienation and self-pity.”

“I always wanted skin like the Thing.”

“It wouldn’t suit you nearly as well as the skin God gave you. But as a way for you to protect your robots from cosmic rays, while giving them the freedom to roam around—”

“I think I’m in love,” she said.

He clapped a bag over his mouth and threw up.

HOW DO YOU TELL THE WORLD THAT IT’S GOING TO DIE? DOOB WAS glad he didn’t have to say it. Instead he just stood behind the president of the United States. His job was to look serious—which wasn’t difficult—as part of a Mount Rushmore of eminent scientists lined up behind a semicircle of world leaders. He stared at the back of J.B.F.’s head as she explained it into a teleprompter. Bracketing her were the Chinese and the Indian presidents, saying the same things at the same time in Mandarin and Hindi. Fanning out into the wings were the prime ministers of Japan, the United Kingdom, France, and (acting as a sort of proxy for most of Latin America, as well as his own country) Spain; the chancellor of Germany; the presidents of Nigeria, Russia, and Egypt; the pope; prominent imams from the main branches of the Islamic faith; a rabbi; and a lama. The announcements were made simultaneously, so that as much of the human race as possible would hear the news at the same instant, and not have to await translations.

If the task had fallen to Dubois Jerome Xavier Harris, Ph.D., he would have said something like this: Look, everybody dies. Of the seven billion people now living on Earth, basically all will be dead a hundred years from now—most a lot sooner. No one wants to die, but most calmly accept that it’s going to happen.

A person who died two years from now in the Hard Rain would be no deader than someone who died seventeen years from now in a car crash.

The only thing that had changed now was that everyone knew the approximate time and manner of their death.

And knowing that, they could make preparations. Some of those were internal: making your peace with your God. Others had to do with passing on one’s legacy to the next generation.

And that was where things got interesting, because none of the traditional legacy-passing schemes was going to survive the Hard Rain. There was no point in drawing up a last will and testament, because all of your possessions were going to be destroyed along with you, and there would be no survivors to receive them.

The legacy was instead going to consist of whatever the people of the Cloud Ark did in the centuries and millennia to come. The Cloud Ark was the only thing that mattered.

They did it at Crater Lake, Oregon. The State Department had commandeered the rustic lodge perched high above the lake on the crater’s rim, flown in the dignitaries, crammed the nearby campgrounds and parking lots with security and media and logistics. At this very moment, marines out on the highway were turning back disappointed holidaymakers, telling them the park was closed, letting them know that they should turn on their radios and listen to the news if they really wanted to understand why. To put the disruption of their vacations into perspective.

The weather was clear, which meant it was cold. The lake down in the crater was the purest blue Doob had ever seen, the sky above it a lighter tint of the same color. He and all the others stood with their backs to it during the announcement. Some political genius on the president’s staff had figured out just how the imagery was supposed to work. The cameras were up on a scaffolding so that they could shoot downward, ensuring that the panorama of the crater, Wizard Island with its sparse covering of trees, and the snow-streaked mountain rim were all there in the high-definition backdrop of the shot. The message was there for anyone who wanted to read it. Between six and eight thousand years ago, an unimaginable catastrophe had befallen this place. The surviving humans had kept the story alive in legends of an apocalyptic struggle between the gods of the sky and of the underworld. Now, it was beautiful. The president and some of the other leaders were weaving that story into their announcements. Doob and the scientists around him—professors from great universities all over the world—couldn’t hear what was being said. The leaders were projecting their words outward into the world, and the sounds coming out of their mouths were swallowed up in the rushing of the wind over rocks and through trees. Doob, four meters behind the president, watched the wind mess with her hair. J.B.F.’s hair had been much commented on during the days before Zero, when such things had actually seemed important to commentators in the world of fashion and politics. It was dusky blond, streaked with silver. She wore it straight and shoulder-length. She was forty-two years old, which made her the youngest president of the United States, edging out J.F.K. by a year. She had flirted with politics during her student years at Berkeley but then opted for an M.B.A. and a stint with a high-powered business consultancy before taking a job at a clever but struggling Los Angeles tech firm. Under her leadership the company had turned its fortunes around to the point where it had been acquired by Google in a deal that had made her wealthy. She had married an actor turned producer, ten years older, whom she had met at a dinner party in Malibu. He already had dogs in various political fights, since a number of his films had been overtly political documentaries or thrillers with political overtones. Latino, with some family history of persecution under Castro, Roberto was something of a political chameleon, mixing libertarianism and populism in a way that intrigued both sides without repelling anyone save the most hard-core extremists. He got away with it because he was handsome, charming, and, as he freely admitted, not book-smart enough to puzzle out all the issues.

Having thus settled into a family life, and made a much-discussed decision to keep her maiden name, Julia Bliss Flaherty had swung her sights around to politics. She had narrowly lost a senatorial race in California. Visibly pregnant by the time Election Day arrived, she had soon given birth to a baby with Down syndrome and become a human Rorschach blot for all sorts of angst around amniocentesis and selective abortion. Making the rounds of talk shows to discuss those topics, she had drawn the eye of national political campaigns on both sides of the aisle. During the following presidential campaign, she had found herself in the unusual position of being on both parties’ vice presidential short lists. She was staunchly middle-of-the-road, with enough ambiguity in her politics to extend the Democrats’ reach rightward and the Republicans’ leftward. No one had expected her to end up in the Oval Office; that was never seriously expected, nowadays, of vice presidents. But the scandal that had brought down the president in only the tenth month of his inaugural year had elevated her to the presidency and made her hairstyle fair game for dissertation-length treatments in the press. Much of it was about those glints of silver. Were they natural, or artificial? If natural, why didn’t she get rid of them? The technology existed. If artificial, then wasn’t it really just a sneaky trick to make her look older, more serious? Either way, should a woman in today’s society need to make herself look matronly in order to be taken seriously?

Doob was pretty sure that no such articles would ever again be written after the announcement that J.B.F. was making today. And indeed he felt the requisite shame over the fact that he was paying any attention whatever to the president’s hair, on this of all days.

But this was how the mind worked. The mind couldn’t think about the End of the World all the time. It needed the occasional break, a romp through the trivial. Because it was through trivia that the mind was anchored in reality, as the largest oak tree was rooted, ultimately, in a system of rootlets no larger than the silver hairs on the president’s head.

The announcements all started at the same time but some went on longer than others, the imams and the pope segueing into prayers. The president and other secular leaders, having finished their remarks, stood there uncomfortably for a minute or two, then began to shuffle away toward aides who enveloped them in big warm coats. Doob and the other scientists, as much a part of the backdrop as Crater Lake, were obliged to remain in place until the last prayers ended.

He thought he might come up here with Amelia and watch it happen. It would be a fine place to observe the White Sky and the beginning of the Hard Rain. During the announcement, he had seen a single bolide streak across the sky south of them, a trail of white fire bright enough to leave a slow-fading blue streak in his vision, popping apart into two, then five discrete chunks before it all went over the horizon. It was too far away for him to feel its radiant heat on his face. But people who had been closer to recent events reported that the warmth was palpable. It was also fleeting, since the bolides came and went at hypersonic velocities. But when the Hard Rain began in earnest, they’d be coming in thick and fast, their fiery trails crisscrossing the sky and then merging into a continuous sphere of broiling heat. Even those people who were fortunate enough—if that was the right word—not to get hit directly by a rock would be driven beneath cover. And it would have to be something like a sheet of metal that would reflect heat and not catch fire. That would buy them some time, but soon the air itself would become too hot to breathe. He had been wondering at what point during all of that he should just end his own life.

It was three weeks and a day since the disintegration of the moon, and a mere twelve days since he had convinced himself that the Hard Rain was going to happen. He was astonished in a way that the world’s leaders had responded so quickly. But they had been driven to it by the spread of rumors. The same calculations had been made by astronomers all over the world. They were accustomed to working in the open, sharing their ideas on email lists. Anyone who really wanted to know, and who had an Internet connection, could have learned about the Hard Rain a week ago. The president and the other leaders, he reckoned, had been impelled to do this sooner rather than later so that they could focus openly on the development of the Cloud Ark.

And also so that they could give the peoples of the world some agency. Not to be confused with the Agent that had torn up the moon. “Agency,” in the lingo of the sorts of people who had set up this announcement, meant giving people options, giving them some things that they could do to have an effect—imaginary or not. There was nothing they could do, of course, about the Hard Rain. And very few of them could contribute on a technical level to the Cloud Ark—there were only so many people qualified to go on space walks or assemble rocket engines, and those had already been mobilized.

But there were things that people could do to help the Cloud Ark achieve its mission, and thereby become a part of the legacy that would be carried forward into space.

Once the announcements and the prayers were finished, three people converged on the central lectern where the president had spoken a few minutes earlier. They were going to talk in English and their words would be translated into as many languages as the organizers had been able to find interpreters for. First up on the dais was Mary Bulinski, the United States secretary of the interior, an inveterate hiker and climber, spry at sixty. By training she was a wildlife biologist. Next was Celani Mbangwa, a big South African woman and a well-regarded artist. Last was Clarence Crouch, the Nobel Prize–winning geneticist from Cambridge, moving slowly on a cane because his own genes had played a nasty trick on him and he had come down with colon cancer. He was being assisted over the rocky ground by one of his postdocs, Moira Crewe, who never seemed to leave his side. Clarence’s wife had committed suicide ten years ago and King’s College was the only thing that was keeping his body and his soul together.

They had all been made aware of what was going to happen several days ago so that they would have some time to recover from the shock and make themselves presentable on television. They had been flown as soon as possible to Oregon and ensconced in rooms at the lodge on the rim. Doob and other scientists, filtering in from all over the world, had set up a kind of war room in a meeting room downstairs, trying to figure out what exactly Mary and Celani and Clarence were going to say. Because that was an essential part of the announcement. No one was really expecting mass panic or chaos. There would be some of that, of course. But billions of people would want to know how they could be useful. And some answers needed to be provided for them.

And so it didn’t matter that Mary and Celani and Clarence were standing with their backs to Doob and talking into a cold wind, because he knew what they were going to say, had gone over the text a hundred times.

Mary’s piece of it was to talk about how the Cloud Ark was going to preserve the genetic legacy of the Earth’s ecosystems, largely in digital form. They couldn’t send giraffes into space, or keep them alive once up there, but they could preserve samples of their tissue. Space was a pretty effective refrigerator. Better yet, the genetic sequences could be recorded by feeding samples into machines, taking the DNA strands apart one base pair at a time, and preserving them as strings of data that could easily be archived and replicated. Special machines would be sent up on the Cloud Ark, machines that could take those digital records and turn them back into functioning DNA and embed them in living cells, so that giraffes and sequoias and whales could be reconstituted from raw elements at some point down the road, perhaps thousands of years in the future. How could ordinary people help? By collecting samples of living things in their environment, especially rare or unusual ones, and taking pictures and GPS readings with their smartphones, and sending them to certain addresses, postage free.

In a way Mary had the hardest job, because this part of the plan was utter BS and she had to know it. Biologists had long ago collected all the samples that mattered. All the flowers and raccoon skulls and bird feathers and sticks and snails that got mailed to those addresses by helpful kids would end up being destroyed. All the genetic sequencing machines were already operating full tilt, around the clock, and the machines that made more of those machines were doing likewise. Nevertheless, she managed to sell it, or so Doob guessed from the set of her shoulders and the movements of her head as she spoke into the teleprompter.

Celani’s job was to convince the people of the world that they could contribute to a literary, artistic, and spiritual legacy that would outlive them. All the world’s books and websites were already being archived. What was wanted now was for people to write stories and poems, draw pictures, or simply aim cameras at themselves and shoot photos or videos that would one day be browsed by the distant descendants of the Cloud Ark pioneers. This was an easier thing to explain convincingly, since it was legitimate, and simple. Archiving lots of digital files and sending them into space was straightforward.

Clarence, the last up, had some explaining to do.

Doob knew the text of his talk by heart. They had discussed various ways of saying this, but Clarence had gravitated toward the High Church phrasings that came naturally to him.

“The time has come for a great Casting of Lots,” he announced. “The Lord has seen fit to populate the Earth with people of many colors and kinds. A burden has now been laid on us, as it was once laid on Noah. Like him we must populate our Ark in a manner respectful of the diversity of life around us. Mary Bulinski has already spoken of how we will preserve the legacy of the world’s plants, animals, and other life-forms. We will not do this as Noah did, by bringing them aboard the Ark two by two. There is not room for them, and there is no way to keep them alive. We go another way where the plants and the animals are concerned.

“The peoples of the world are a different matter. We will need people in that Ark. It is not an automatic mechanism. It will require the ingenuity and adaptability of human minds. We will populate it. We will begin with astronauts, cosmonauts, military, and scientists whose skills are needed. But there are only so many of those, and they are drawn from only a small portion of the world’s peoples.”

This question—how many?—had bedeviled them all along. In two years, how many humans could be launched into space, assuming that rocket factories all operated full-time, and we weren’t too fussy about safety procedures? Estimates varied through two orders of magnitude, from a few hundred to tens of thousands. They had no idea. And it was one thing to get them up there and another thing to keep them alive. The most solid estimates that Doob had seen were converging on a number somewhere between five hundred and a thousand. But they had carefully scrubbed Clarence’s speech of any specific numbers, or even hints.

“We ask every village, town, city, and district to perform a Casting of Lots and to choose two young persons, a boy and a girl, as candidates for training and inclusion in the crew of the Cloud Ark. We do not seek to impose any rules or procedures upon how the selection is made. Our objective is to preserve, as best we can, the genetic and the cultural diversity of the human race. We trust that the candidates selected will exemplify the best features of the communities from which they were chosen.”

The statement was subtly self-contradictory. Clarence was saying that they were not going to impose any rules. But they had already done so by insisting that there had to be both a boy and a girl. They knew perfectly well that many cultures would have trouble with that.

“The boys and the girls so chosen,” Clarence went on, “will be gathered together in a network of camps and campuses, where they will be trained for the mission they are to undertake, and launched into the Cloud Ark as room is made for them.”

Doob, aware that he might be in the background of some camera angle, did his best to maintain a poker face. Clarence wasn’t exactly lying. But he was leaving a lot out. How many boys and girls would end up in those camps? More than could be transported to or accommodated in any conceivable space ark. How many of them could really be trained to do anything useful?

In reality it would be much more selective than Clarence made it sound. Only some of those chosen in the Casting of Lots would actually be collected. Those belonging to rare or distinctive ethnic groups probably had a leg up. Once they got to the training center, they would begin to understand that not all of them were actually going to get launched into space before the Hard Rain. It would get competitive. Perhaps brutally so. Doob didn’t like to think about it.

For the thousandth time in the last three weeks, he mused about how funny the mind was. It didn’t matter that conditions in the training camps might become unpleasant. It was nothing. And yet the thought of young persons being cruel to each other upset him more than the fact that most of them were going to die.

A curtain twitched up in a window of the lodge, and Doob looked to see Amelia, arms crossed, elbows on the windowsill, looking down at him from the room they had shared the last three nights. She had stayed inside so that she could watch it on the TV in the room, let him know how it had looked on video, how the commentators and pundits had framed it.

It was Thanksgiving week. School was out. She’d flown up to Eugene on Wednesday, rented a car, and driven here to be with him.

The staff at the lodge, still unaware of what was about to happen, had served the traditional turkey dinner on Thursday afternoon. The scientists, politicians, and military who had come here from all over the world to contemplate the end of days had tried to see the humor in the holiday. In a way, though, Doob actually was thankful. He was thankful that Amelia had come up to spend time with him. He was thankful that she had shown up in his life at exactly the moment when he most needed to have someone around.

On Day 7, when he had met Amelia and fallen for her in the same instant, he’d felt foolish. He’d wondered what was going on in his brain for it to react so. But she’d let him know, in the correct, even steely manner of an elementary school teacher, that the interest was reciprocated. The school where she taught was less than a mile from the Caltech campus and so they would get together for quick early dinners before she went home to grade papers and he went back to his office to check and recheck his calculations about the exponential, the White Sky. The split between the joy of new love and the growing awareness of what was going to happen was almost too wide for his mind to address. He would wake up every morning and enjoy those first few moments of consciousness before his mind swung uncontrollably to one topic or the other.

After he had come back from Camp David and the teleconference where he’d explained matters to the crew of the International Space Station, she had asked him what was troubling him, and he had told her. That night was the first time they had slept together. But they slept together four times before he found himself able to have sex. It wasn’t so much the dread of the catastrophe that got in the way. Disasters could be sexy. He’d had some of the best sex of his life while on the road to attend loved ones’ funerals. What weighed him down and left him impotent was the stress and distraction of having to communicate what he knew to one person at a time.

Problem solved. Everyone knew now.

Clarence wound up his announcement with some inspiring talk about how the young men and women who ascended to the safety of the Cloud Ark would build a new civilization in space and populate it with the genetic legacy of all mankind. Frozen sperm, eggs, and embryos would be sent up there too, so that even those who were left behind to die on the Earth’s surface could enjoy some hope that their offspring would one day grow to maturity in orbiting space colonies, and commune with their departed ancestors through digitally preserved letters, photographs, and videos. To Doob, this part of the talk seemed tacked on, something put in there just to hold out a glimmer of hope. But he knew that it was, in a way, the most important thing that any of the speakers would say today. The rest of the message had been stunningly grim, too shocking for most people to take in. The news anchors covering the announcement had been sworn to secrecy and briefed on it yesterday, just to give them some time to recover emotionally in the hope that they could hold it together on air. The announcement had to conclude with some straw for people to grasp at. This kindly, ancient Cambridge professor, hollowed out by cancer, speaking in the cadences of the King James Bible about the new world in the heavens that would be populated by the children of the dead, venerating their ancestors’ JPEGs and GIFs, was the closest thing to an uplifting message that anyone was going to see today. He had to sell it, and he did. And Doob and all the other scientists who were now running the Cloud Ark program, along with the world’s military and politicians and business leaders, had to follow through.

Moira Crewe, Clarence’s postdoc, and Mary Bulinski each got a hand under one of Clarence’s arms and helped him down the steps to the rim of the crater, where a few shell-shocked journalists had gathered to ask questions. For the most part, though, the place was dead quiet. None of the usual post-news-conference hubbub. Most of the networks had cut back directly to their headquarters.

Doob looked up at the window. Amelia tucked her hair behind her ear and drew back from the glass. He trudged back to the lodge on legs stiff with cold. He was thinking about those frozen sperm samples and eggs. How long would they last? It was known that such cells could be thawed and used to produce normal babies after as long as twenty years in the freezer. Cosmic rays might complicate things. A single ray passing through a human body might damage a few cells—but bodies had a lot of spare cells. The same ray passing through a single-celled sperm or egg would destroy it.

The bottom line was that every man now on Earth could ejaculate into a test tube, every woman could go in for the much more complicated process of having her eggs harvested, embryos could be gathered and put on ice by the millions, but none of it would make a bit of difference unless there were healthy young women willing to receive those donations into their own wombs and gestate them for nine months. In time the population would grow. A new generation of—to put it bluntly—functional uteruses would come online in fourteen or fifteen years. And a second generation would be available in thirty. But by then, many of the frozen samples that the people of Earth were pinning their hopes on would be past their expiration dates.

Most of the people on the Cloud Ark were going to have to be women.

There were other reasons for it besides just making more babies. Research on the long-term effects of spaceflight suggested that women were less susceptible to radiation damage than men. They were smaller on average, requiring less space, less food, less air. And sociological studies pointed to the idea that they did better when crammed together in tight spaces for long periods of time. This was controversial, as it got into fraught topics of nature vs. nurture and whether gender identity was a social construct or a genetic program. But if you bought into the idea that boys had been programmed by Darwinian selection to run around in the open chucking spears at wild animals—something that every parent who had ever raised a boy had to take seriously—then it was difficult to envision a lot of them spending their lives in tin cans.

The system of camps where the young people chosen in the Casting of Lots would be taken for training and selection was going to be a roach motel for boys. Young men would go in, but they wouldn’t come out. Save for a few lucky exceptions.

He had been drifting toward the lodge for a couple of minutes, nagged by the vague sense that there was something he ought to be doing.

Talking to the media. Yes, that was it. Normally, camera crews would be homing in on him. And normally he would be trying to dodge them. But not today. Today he was willing to stand around and talk, to be Doc Dubois for the billions of people out there in TV land. But no one was coming after him. Anchors of many nations were gazing soulfully into their teleprompters, intoning prepared remarks. Journalists of lesser stature—tech bloggers and freelance pundits—were filing their reports. Doob noticed a familiar face, Tavistock Prowse, off in a corner of the parking lot. He had set up a tablet on a tripod, aimed its camera at himself, and clipped on a wireless mike, and was delivering some kind of a video blog entry, probably for the website of Turing magazine, which had employed him for these many years. Doob had known him for two decades. He looked terrible. Tav had showed up this morning. He didn’t have the credentials or the access to get the advance warning, so all of this was news to him. Doob had pinged him a few times last night, on Twitter and Facebook, trying to give him a heads-up so that his old friend wouldn’t be wrong-footed by the announcement, but Tav hadn’t responded.

It didn’t seem like a great moment to be doing an impromptu interview with Tav and so Doob pretended he had not seen him. He flashed his credentials at the Secret Service guys stationed at the lodge’s entrance, but this was just to be polite—they knew who he was and had already pulled the door open for him.

He passed the elevators and climbed the stairs to the room, just to get blood moving in his extremities. Amelia had left the door ajar. He hung up the DO NOT DISTURB placard, locked the door behind him, and collapsed into a chair. She was still at the window, leaning back perched on its broad rustic sill. This side of the lodge was facing away from the sun, but the light of the sky came in and illuminated her face, showing the beginnings of lines below her eyes, around her mouth. She was second-generation Honduran American, some kind of complicated African-Indian-Spanish melange, big eyed, wavy haired, alert, birdlike, but with that essentially positive nature that any schoolteacher needed to have. It was a good trait in current circumstances.

“Well, that’s over,” she said. “It must be a big load off of your mind.”

“I have ten interviews in the next two days,” he said, “explaining the whys and the wherefores. But you’re right. That’s easy, compared to breaking the news.”

“It’s just math,” she said.

“It’s just math.”

“What about after that?” she asked.

“You mean, after the next couple of days?”

“Yeah. Then what?”

“I hadn’t really thought about it,” he admitted. “But we have to keep gathering data. Refining the forecast. The more we know about when the White Sky is going to happen, the better we can plan the launch schedule, and everything else.”

“The Casting of Lots,” she said.

“That too.”

“You’re going, aren’t you, Dubois?” She never called him by his nickname.

“Beg pardon?”

Irritation flashed over her face—unusual, that—and then she focused on him, and she gradually became amused. “You don’t know.”

“Don’t know what, Amelia?”

“Obviously, you’re going.”

“Going where?”

“To the Cloud Ark. They’re going to need you. You’re one of the few who can be useful up there. Who can actually help its chances of survival. Be a leader.”

It really hadn’t occurred to him until she said it. But then he saw that it was probably true. “Oh, Jesus Christ,” he said, “I think I would rather croak down here. With you. I was thinking we could come up here, camp out on the rim, and watch it. It’s going to be the most amazing thing ever.”

“A real hot date,” Amelia said. “No, I think I’ll be spending that day with my family.”

“Maybe you and I could be family by then.”

Tears gleamed in the pouches beneath her eyes, and she ran a finger under her nose. “That has got to be the strangest proposal ever,” she said. “The thing is, Dubois, that my husband is going to be in orbit and I’m going to be in California.”

“I could look for a way to—”

She shook her head. “They will never, ever agree to bringing a thirty-five-year-old schoolteacher up to the Cloud Ark.”

He knew she was right.

“A frozen embryo, though—that seems like a possibility.”

“That has got to be the strangest proposition ever,” Doob said.

“We live in strange times. I’m fertile right now. I can tell. No more condoms for you, tiger.”

So it was that, half an hour after Doc Dubois had listened with high intellectual skepticism to the soothing speech of Clarence Crouch, and picked it apart logically in his mind, proving to himself that it was just a comforting sop for the bereaved billions, a distraction to keep them busy with sex during the two years they had left, he was in Amelia’s arms, and she in his, as they got busy making an embryo for him to carry up into space for implantation in some other, unknown woman’s womb.

He was already thinking about the videos he was going to make to teach his baby about calculus when he climaxed.

DINAH WAS GLAD NOT TO HAVE BEEN ON THE PLANET WHEN THE Crater Lake announcement was being made. She sat alone in her workshop, peering out her window past the craggy black silhouette of Amalthea at the luminous blue limb of the Earth below. She knew the time of the announcement and she knew how long it was supposed to last. She chose not to watch the video feed. It hit her as strange that the Earth itself did not change its appearance in any way. Down below, seven billion people were hearing the worst news imaginable. They were going through a collective emotional trauma unknown in the history of the human race. Police and military were being deployed in public spaces to “maintain order,” whatever that meant. But Earth looked the same.

Her radio started beeping. She looked down, blinked away tears, and saw Alaska, bent over the curve of the world far to the north.

WE ARE PROUD THAT YOU ARE UP THERE

She recognized her father’s fist—his touch on the Morse key—as easily as his smell or his voice. She returned:

I WISH THAT I COULD SEE YOU AGAIN

AUNT BEVERLY IS SOWING SOME FLATS OF POTATOES. WE WILL BE FINE.

She cried for a while.

QSL, he signaled, which was a Q code meaning, in this case, “Are you still there?”

She sent QSL back, meaning “Yes.”

She knew that the purpose of Q codes was to make communication more efficient, but she understood now that they could serve another purpose. They could enable you to eke out a few scraps of useful information when words were too difficult.

YOU BETTER GET TO WORK KIDDO

AND YOU SHOULD STOP POUNDING THAT KEY AND HELP BEV

LOVE YOU QRT

QRT

“It’s still a miracle to me that you can make sense of that.”

She turned around to discover Rhys Aitken, poised in the hatchway that connected her shop to the SCRUM: the Space Commercial Resources Utility Module, which was the large can-shaped object that connected Izzy’s forward end to Amalthea. Along its sides, the SCRUM sported several docking ports where other modules could be connected. Owing to various delays and budget cutbacks, only one of those ports was currently in use, and Rhys was now hovering in it. Tucked under one of his arms was a bundle, wrapped in a blanket.

She sniffled, suddenly aware that she was a mess. “How long have you been there?”

“Not long.”

She turned her back on him, grabbed a towel, and dried her eyes and nose. Rhys filled the time with some gentle patter. “I couldn’t stand watching the announcement any longer, so I tried to make myself useful. Discovered something marvelous. Water runs downhill. All right, I already knew that, actually. There’s a section of the torus, underneath the deck plates, where condensation tends to collect—it’s been a maintenance issue, something we’ve been keeping an eye on.

“So, I brought you something,” he concluded.

She turned and looked at the bundle under his arm. “A dozen roses?”

“Perhaps next week. Until then—” and he held it out.

She took it from him. Like everything else up here it was, of course, weightless, but she could tell by its inertia that it had some heft.

She peeled back the blanket and heard a crinkling, crackling noise, then saw underneath it a layer of the metallized Mylar sheeting that they used all over Izzy as thermal shielding. The object beneath that was lumpy and irregular. And it was cold. She peeled away the Mylar to reveal a slab of ice. It was oval and lens shaped: a frozen puddle.

“Perfect,” she said.

A few drops of water spun away from it, gleaming like diamonds in the shaft of sunlight spearing in through her little window. She captured them using the same towel she’d just used to dry her face. But not before pausing, just a moment, to admire their brilliance. Like a little galaxy of new stars.

“You’d said something about a cryptic message from Sean Probst.”

“All of his messages are that way,” she said, “even after they’ve been decrypted.” Sean Probst was her boss, the founder and chairman of Arjuna Expeditions.

“Something about ice, anyway,” Rhys went on.

“Hang on, let’s get this in the airlock before it melts any more.”

“Right.” Rhys pushed himself to the far end of the shop, where a round hatch, about half a meter in diameter, was set into the curved wall. “I see green blinkies all about, so I’ll just open this?”

“Fine.”

He actuated a lever that released the latching mechanism, then pulled the hatch open to reveal a little space beyond. This was the airlock that Dinah used when she needed to bring one of her robots inside for maintenance, or send one back out onto Amalthea. Human-rated airlocks were big—they had to accommodate at least one person in a bulky space suit—and complicated and expensive, partly because of safety requirements and partly because they were designed by government programs. This one, by contrast, had been prototyped in a few weeks by a small team at Arjuna Expeditions, and was meant for smaller equipment. It was roughly the dimensions of a big garbage can. To save space on the inside, it protruded from the side of the module, jutting into space like a stubby, oversized fire hydrant. At its far end was a dome-shaped hatch that Dinah could open and close from inside her shop using a mechanical linkage of pushrods and levers straight out of a Jules Verne novel. At the moment, of course, that hatch was closed, and the airlock was full of air that had gone chilly, since the sun had not been shining on its outside until a few minutes ago.

Dinah gave the chunk of ice a gentle push and it glided across the shop to Rhys. “Up and under!” he called, and caught it.

“What?”

“Rugby,” he explained, and slid the ice into the airlock. “Have you got a Grabb or something that can come round and fetch this?”

“In a minute,” she said. “It’ll keep in there for now.”

“Right.” He closed the inner door and dogged it shut. Then he turned back and looked at Dinah, and she looked at him, and they appraised each other for a few moments.

“So water condenses and puddles at this one place in the torus,” she said, “which you can reach by pulling up a deck plate?”

“Yes.”

“And it freezes?”

“Well, normally, no. I may have helped it freeze by fiddling with certain environmental controls.”

“Ah.”

“Just trying to save energy.”

She was floating in the opposite end of the shop, near the hatch where it connected to the SCRUM. She looked through and verified that no one was around. Some of them, she knew, were in a meeting in the torus, and others were doing a space walk.

“Now, technically …” she began.

“Technically, this is wrong,” he said. She admired the self-aware bluntness. “It is wrong because when you open the outer hatch and put that piece of ice out in space, where your robots can muck about on it, it is going to sublimate.”

Sublimation was essentially the same thing as evaporation, skipping the liquid phase; it just meant a process by which a solid, exposed to vacuum, gradually turned into vapor and disappeared. Ice tended to do this pretty quickly unless it was kept extremely cold.

“So Izzy is going to lose water,” Dinah said, “which is a scarce and valuable resource.”

“It’ll never be missed,” Rhys said blithely. “This isn’t the old days. Now that those people have made that announcement, rockets will be coming up here thick and fast.”

“Still, what Sean wants me to do is an Arjuna Expeditions project. A commercial thing. A private thing. And that water is a shared—”

“Dinah.”

“Yes?”

“Snap out of it, love.”

A long silence followed, concluded by a big sigh from Dinah. “Okay.” Rhys was right. Everything was different now.

“Now, what is it he wants, and how does ice enter into it?”

Her mild annoyance at his curiosity finally gave way. Maybe he could help. She turned her head toward the window and nodded at the familiar bulk of Amalthea, a few meters away. “That’s been my career, and my family’s career,” she said. “Working with minerals. Hard rock. Metallic ore. All of the robots are optimized for crawling around on a big piece of iron. They use magnets to stick to it. Their tools use plasma arcs or abrasive wheels to work it. Now, Sean’s basically telling me to shelve all of that. The future is ice, he says. That’s all he wants to hear about. All he wants me to work on.”

“There’s lots of it on Earth,” Rhys pointed out, “but you never think of it as a mineral.”

She nodded. “It’s an annoyance you have to clear out of the way.”

“Your colleagues down on the ground? Also working on ice?”

“Judging from email traffic, this is a company-wide directive,” she said. “They’re buying ice by the truckload, dropping it on the floor of the lab, refrigerating the building—fortunately it’s winter in Seattle; they only need to drop the temperature a few degrees. They’re all buying long underwear at REI so that they can work in a refrigerator.”

“What’s it like working for Mr. Freeze?”

“I was going to say the Penguin,” Dinah said, “but people in Seattle don’t carry umbrellas.”

“Nor do they wear top hats, in my experience. No, it’s definitely a Mr. Freeze scenario.”

“Anyway,” Dinah said, “yesterday’s shipment of vitamins contained a few of these.”

She opened a storage cubby next to her workstation and took out a bag made of the metallic gray plastic used to protect sensitive electronics from static electricity. Taped to it was a NASA business card.

“Nice to have friends in high places,” Rhys remarked. He had noticed the name on the card: Scott “Sparky” Spalding, the NASA administrator.

Dinah smiled. “Or low, as the case may be.”

It was a weak joke. Rhys didn’t respond. Dinah felt her face get a little warm. Not so much because of the failed attempt at humor as out of a kind of political defensiveness. “Scott told me a couple of weeks ago that he wouldn’t ditch me out. That he had my back.”

“What does that mean exactly?”

“That the robot work would keep going. That I would have a job. I didn’t believe him. But I guess he’s been talking to Sean Probst. Because Sean FedExed these to Sparky a couple of days ago, and now they’re here.”

She parted the bag’s ziplock closure, inserted her thumb and index finger, and pulled out a contraption about the size of a grain of rice. From a distance it looked like a photovoltaic cell, just a flake of silicon, but with a few tiny appendages.

“What are the dangly bits?” Rhys wanted to know.

“A locomotion system.”

“Legs?”

“This one happens to have legs. Others have things like little tank treads, or rolling cylinders, or slammers.”

“Slammers? Is that a technical term?”

“A mining thing. A way of moving heavy equipment around on the ground. I’ll show you later.”

“So,” Rhys said, “it would appear that the agenda is to evaluate a number of different ways that robots could crawl around on ice without drifting off and getting lost.”

“Yeah. Apparently all of these work, more or less, on the ground in Seattle. I’m supposed to evaluate their performance in space.”

“Well!” Rhys said. “How fortunate for you, then, that—”

“That I have my very own chunk of ice. Yeah. Thanks for that.”

“All the sweeter for being contraband?” he asked, raising his eyebrows.

The double meaning was clear enough. “Not as romantic as a dozen roses,” she countered.

“Still,” he said, “what is it that a man is trying to say with a dozen roses? Simply that he is thinking of you.”

Shortly after she’d arrived on Izzy she had rigged up a curtain that she could draw across the opening of her shop’s hatch. It wasn’t much—just a blanket—but it shielded her visually when she wanted to take a nap in her shop, and it sent the message that she was not to be disturbed, at least without knocking first. She reached up now and drew the curtain across the hatchway. Then she turned back toward Rhys, who looked very keen, and very ready.

“How’s your space sickness?” she asked. “You seem a little more, uh, sprightly.”

“Never better. All bodily fluids fully under control.”

“I’ll be the judge of that.”

THE RUSSIAN INVASION BEGAN A WEEK LATER, WITH A SPATE OF flights producing what NASA described as “mixed results” and Roskosmos termed “an acceptable fatality rate.”

Seen from a distance, Izzy consisted almost entirely of solar panels. Structurally, these were to the space station as the wings of a bird were to its body, in the sense that their purpose was to have as much surface area as possible with minimal weight.

Most of the mass, strength, and brains were in the “body”—a stack of can-shaped modules running up the middle between the “wings”—which was tiny by comparison. From many angles you couldn’t even see it. The only parts of the stack big enough to be noticed from a distance were the add-ons from recent years: Amalthea at one end and the torus at the other.

The solar panels—as well as some other, vaguely similar-looking structures whose function was to radiate waste heat into space—were held in place by the Integrated Truss Assembly. The word “truss,” when used by structural engineers, just meant something that looked like a radio tower or a steel bridge: a network of struts joined into a lattice, giving maximum stiffness with minimum weight. In some parts of Izzy, those struts were visible, but more commonly they were covered up by panels that made them look more solid than they were. Behind those panels resided unfathomably complex wiring, plumbing, batteries, sensors, and mechanisms for deploying and rotating solar panels. With a few minor exceptions, none of the Integrated Truss Assembly was pressurized—none of it was meant to hold air or accommodate human beings. It was like the mechanical works on the roof of a skyscraper, exposed to the elements and rarely visited by humans. Astronauts went there on space walks to mess with the wiring or fix things that weren’t working, but most of Izzy’s crew spent their whole missions inside the much smaller stack of cans that made up the station’s “body.”

That was going to have to change.

Izzy herself could only expand so much. This was not a question of stacking on more cans, or adding additional tori. Beyond a certain point you simply couldn’t jam more complexity into such a focused volume. Electrical power was needed to run just about everything. Whenever it was used, waste heat was generated. The heat would build up in the space station and cook the occupants unless it was collected by a refrigeration system and piped out to radiators that would “shine” the heat, in the form of infrared light, into space. Jamming more people and systems into the central body of the space station would just require more solar panels, more batteries, more radiators, and more plumbing and wiring to connect them all. And this didn’t even address the human factors: how to supply people with food, water, and clean breathable air, and how to recycle carbon dioxide and sewage.

Knowing this, the brain trust behind the Cloud Ark—an ad hoc working group of governmental space agency veterans and commercial space entrepreneurs—had opted for the only strategy that could possibly work, which was decentralized and distributed. Each arklet, as the component ships were being called, would be small enough that it could be heaved into orbit on the top of a single heavy-lift rocket. It would draw power from a small, simple nuclear reactor fueled by isotopes so radioactive that they would throw off heat, and thereby generate electricity, for a few decades. The Soviet Union had used such devices to power isolated lighthouses, and they had been employed in space probes for decades.

Each arklet would accommodate a small number of people. The number kept changing as different designs were drawn up, but it meandered between about five and a dozen. Much depended on how rapidly it would prove feasible to mass-produce inflatable structures; these made it possible to create much more spacious volumes by housing people in what amounted to thick-skinned balloons. But making balloons that could withstand atmospheric pressure indefinitely while also standing up to solar radiation, thermal swings, and micrometeoroids was no small project.

It went without saying that, in the long run, the Cloud Ark as a whole was going to have to be self-sustaining in terms of food production. Water would have to be recycled. Carbon dioxide exhaled by humans would have to be used to sustain plants, which would produce oxygen for the humans to breathe and food for them to eat. All of this had been the subject matter of science fiction stories and practical experiments for decades. Those experiments had produced mixed results that were now getting a lot of attention from people who understood such things a lot better than Dinah. But she gathered that she had better get used to a low-calorie vegetarian diet, and occasional oxygen shortages.

Isolated arklets wouldn’t survive for long. It didn’t matter how good their internal ecosystems were. Things would go wrong, people would get sick, supplies and nutrients would run low, and people would just plain go crazy from being cooped up with the same few individuals.

The design of the arklets, and of the whole Cloud Ark system, kept changing. One day it was all about being “fully distributed,” which meant that in the long run there was no central depot—no Izzy—and that all exchanges of material and “human resources” between arklets would happen through “opportunistic docking,” meaning that two arklets would agree to come together and connect nose-to-nose for a time so that food, water, vitamins, or people could be exchanged. This was envisioned as market driven, without any central command and control mechanism.

The next day a new edict would be handed down to the effect that overall coordination would be handled by a command center on Izzy. The space station would also serve as a central depot for anything that could be stockpiled. The torus—or tori, since Rhys was on track to construct a second one—would be available for rest and recreation; arklet dwellers going stir-crazy from living in tin cans and suffering loss of bone density from floating around in microgravity would be rotated through and allowed to vacation there.

The schemes envisioned by the Arkitects, as Dinah and Ivy started calling them, ping-ponged back and forth between those two extremes, and seemed to reflect the existence of at least two factions. The centralizing faction pointed to the dangers of prolonged zero-gee existence as a reason for rotating people through the torus. The decentralizers came back a couple of days later with a sketch of the so-called bolo scheme, wherein a pair of arklets would connect to each other with a long cable and then begin spinning around their common center of mass, creating simulated gravity in each arklet that was stronger and better than what could be achieved in a torus. A couple of days after that, the centralizers posted an animated simulation of what would happen when two bolos ran into each other and got their cables tangled. It was funny in a kind of slapstick-horror way.

None of this really mattered in the short term, because, even on a hysterically accelerated schedule, it was going to take weeks to design and manufacture even a single arklet. And it would take longer to ramp up the production lines for the giant heavy-lift rockets needed to boost them into space. What Izzy’s crew would be seeing in the meantime was a hodgepodge of preexisting spacecraft, mostly Soyuz capsules, being sent up using the existing stock of rockets. These would carry “Pioneers” whose job would be to build new extensions onto Izzy’s Integrated Truss Assembly: for docking many arklets at a time, for storing material, and for making it all run. The Pioneers would spend most of their time in space suits performing EVAs: extravehicular activities, a.k.a. space walks. There would be something like a hundred Pioneers all told. They were being trained now, and their space suits were being hastily manufactured.

But Izzy in her current form couldn’t support anything like a hundred new people. She didn’t even have the spacecraft docking ports needed to berth their vehicles when they arrived. So in order to accommodate the Pioneers who would begin arriving in a few weeks, the Arkitects sent up Scouts. The qualifications for being a Scout seemed to be a shocking level of physical endurance, a complete disregard for mortal danger, and some knowledge of how to exist in a space suit. All of them were Russian.

There wasn’t room for them on the space station. Actually, to be precise, there was plenty of physical space to accommodate them, but the support systems weren’t there. The CO₂ scrubbers could only handle the output of so many lungs. The entire space station had only three toilets, one of which was almost twenty years old.

The Scouts were going to live most of the time in their space suits. This made sense as far as it went, since their mission was to work to exhaustion every day. Sixteen hours in a space suit meant sixteen hours that the Scout was not imposing a direct burden on Izzy’s life support systems.

At Zero, the total number of functioning space suits in the known universe had been something like a dozen. Production had been ramped up since then, but they were still a scarce resource. In its most common form, the Orlan space suit used by the Russians could only function independently for a couple of hours, which was fine since normal people were completely exhausted by that point anyway. Beyond that, its internal reserves were used up. So, the Scouts would mostly be working on umbilicals. Their suits would be connected to an external life support system by a bundle of plumbing and cables that would supply air and power while taking away waste and excess heat.

During the few hours they were allowed to rest, the Scouts needed a place to go and to climb out of their space suits.

Whoever was running things at Roskosmos had pulled up an old idea for an emergency crew rescue device and begun actually producing them. It was called Luk. The word meant “onion” in Russian. It was pronounced similarly to “Luke,” but English speakers inevitably started calling it “Luck.”

In the best traditions of Russian technology, Luk was straightforward. Take a cosmonaut. Enclose him in a large plastic bag full of air.

With any normal plastic bag material, the cosmonaut will suffocate or the bag will pop, because plastic bags aren’t strong enough to withstand full atmospheric pressure. So, fill the bag with only as much air as it can handle—some fraction of one atmosphere—and then place another bag inside of it. Inflate that bag with air at slightly higher pressure. That’s still not enough air to keep a cosmonaut alive, so put a third bag inside of the second bag and inflate it to higher pressure yet. Keep repeating, like with Russian nesting dolls, until the innermost bag has enough air pressure to keep a human alive—then put the cosmonaut inside of that one. All of those layers of translucent plastic gave it an appearance reminiscent of an onion.

The scheme had many advantages. It was cheap, simple, and lightweight. Deflated, a Luk could be pleated and rolled up for storage in a backpack-sized container.

Of course, the air inside the innermost bag would get fouled with carbon dioxide as the occupant breathed, but this could be handled as it usually was on spaceships and submarines, by passing the air over a chemical such as lithium hydroxide that would absorb the CO₂. As long as a bit of oxygen was bled in to replace what was being used, the occupant would be fine.

Heat produced by the occupant’s body would build up in the atmosphere of the innermost bag and become stifling. A cooling system was required.

Getting in and out of the Luk could be problematic. The Russians had somehow determined that just about anyone—or at least anyone capable of meeting the physical standards of the cosmonaut program—could force their body through a hole forty centimeters in diameter. Accordingly, each Luk included a flange—a forty-centimeter ring of fiberglass with bolt holes spaced around its periphery. All the layers of plastic converged on it, further enhancing its onionlike appearance. This became the onion’s cut-off stem. To keep the air from rushing out through that forty-centimeter hole, it was equipped with a stout diaphragm of much thicker plastic that could be put into place after the cosmonaut had climbed inside.

So, the general procedure for using the Luk was to unfold the bag and find the flange, then pull it over one’s head, squirm through it until the shoulders and pelvis had passed through, draw the feet up inside of it, then find the diaphragm and lock it into place, sealing oneself inside. At this point the Luk was still a giant wrinkled mass of plastic hanging around the occupant like a sleeping bag.

Once the Luk was free in the vacuum of space, it was okay to open the valve that flooded air into its many interstitial layers. Whereupon it would expand to the size of a mobile home, and drift around aimlessly until a rescue vehicle could get to it.

On its outer hatch, the rescue vehicle would need to have an adapter with a bolt pattern made to engage with the holes on the Luk’s flange. Once an airtight connection had been made between Luk and vehicle, the hatch could be opened, the diaphragm removed, and the cosmonaut brought in from the cold. Or, given the difficulties of getting rid of excess thermal energy in space, from the heat.

The Orlan suit was built around a hard upper torso, or HUT: a rigid shell for containing the wearer’s trunk, with connection points for the arms, legs, and helmet. The back of the HUT was a door with an airtight gasket around its edge. To put the suit on, you opened that door, threaded your feet down the legs, thrust your hands along the arms and into the attached gloves, and ducked into the helmet. The door was then closed behind you. From that point on the suit was an independent system.

Roskosmos had constructed a number of Vestibyul modules, this being a newly invented thing that they had cobbled together from existing parts in about two weeks. Its purpose was to serve as a jury-rigged bridge connecting Luk to Orlan.

The Vestibyul was barely large enough to accommodate a supine human. At one end was a flange that mated with the forty-centimeter ring on a Luk. Having slithered feetfirst from the Luk into the Vestibyul, a cosmonaut had just enough wiggle room to get his feet aimed down the legs of the Orlan suit that was attached to the other end, its door hanging open. Before doing this, however, he would seal off the Luk by manually putting its diaphragm into position and bolting it into place with a ratchet wrench.

Having donned the Orlan, he could then activate a mechanism, built into the Vestibyul, that would close the suit’s door behind him. The small amount of residual air in the Vestibyul would hiss out into space and the cosmonaut would be free to depart. At the end of the workday, the whole procedure was reversed. Just like a suburban commuter sleeping in a split-level home with his car parked in the garage, the cosmonaut would enjoy a few hours of rest and relaxation floating around the confines of the Luk with his space suit docked at the end of the adjoining Vestibyul.

There were a number of catches.

 Luk, Vestibyul, and suit formed a closed system. The only way to escape from that system was to successfully don the suit, get the door closed, and spacewalk to an airlock. If anything went wrong that prevented donning the suit and closing the door, rescue was impossible, or at least spectacularly improbable. A perforated Luk, probably caused by a micrometeoroid, caused a fatality on the second day of the Scout program. After that, the Luk/Vestibyul systems were brought forward to huddle in the shelter of Amalthea. The asteroid wouldn’t stop all incoming rocks, but it would stop many.

 Since there was no practical way in or out of the system, the Scouts had to fly up from Baikonur in their space suits, preattached to their Vestibyuls and Luks. This was necessitated anyway by the fact that none of this equipment could be accommodated inside of a normal space capsule. So they had to fly up crammed, six at a time, into cargo carriers that were not rated for human use and that had no onboard life support. They were, therefore, living off their space suits’ internal supplies of air and power from shortly before launch until their arrival at ISS. This journey could not be accomplished in less than six hours and so supplemental air and power had to be delivered to the suits en route. The failure of systems responsible for doing that accounted for two fatalities in the first crew of six Scouts and one fatality in the second crew.

 The capabilities of the suits were being wildly overstretched by these new mission parameters, and of course the Luks didn’t really have significant life support systems of their own, so everything depended on umbilical lines that linked these contraptions to Zavod modules. Zavod was simply the Russian word for “factory.” This was another new device that had been cobbled together in two weeks from existing technology. As long as the Zavod was supplied with power, water, and a few consumables, it was supposed to keep a cosmonaut alive by scrubbing CO2 out of the air, collecting urine, and removing their body heat. The heat was gotten rid of by freezing water on a surface exposed to the vacuum and then letting it sublimate into space. Failures of Zavod modules accounted for four fatalities among the first three crews sent up. Two of these were caused by a bug in the software, subsequently fixed by a patch transmitted up from the ground. One was a leaky hose. The other was never explained, but the fatality was witnessed by Izzy’s crew, watching through windows and video feeds, and seemed to match the profile for hyperthermia. The cooling system had failed and the cosmonaut had lost consciousness and succumbed to heatstroke. After that, they had stopped using the jerry-built cooling systems that had shipped up with the Luks and simply used ziplock bags full of ice, delivered daily.

None of this even accounted for mishaps that occurred while the Scouts were actually working. A damaged umbilical nearly killed a Scout on A+0.35, and he was obliged to disconnect himself from his Zavod and execute a heroic and perilous move to the nearest airlock, where they got him inside the space station with less than a minute to spare.

Two days later a Scout simply disappeared without explanation, possibly the victim of a micrometeoroid, or even of suicide.

So, of the first crew of six Scouts, two were dead on arrival and one was killed in the Luk failure the next day. Of the second crew, one was dead on arrival. All six of the third crew made it to Izzy alive. Of the fourteen total survivors, four died from Zavod failures, one disappeared, and one was forced to “retire” from being a Scout and confine his activities to Izzy because of equipment failure.

Ivy, being at the top of the org chart, was responsible for all strange and extraordinary decisions: the problems that no one else knew how, or was willing, to handle. It became her problem to decide what they were going to do with dead people.

Oh, there was a procedure. NASA had a procedure for everything. They had long ago anticipated that an astronaut might die of a heart attack or some mishap during a mission. Since two hundred pounds of rotting flesh could not be accommodated inside of the space station where people lived and worked, the general idea was to let them freeze-dry in space, and then place them aboard the next earthbound Soyuz capsule. Only the middle section of the Soyuz, the reentry module, ever made it back to Earth. The spheroidal orbital module, perched on top of it, was jettisoned before reentry. Eventually it burned up in the Earth’s atmosphere. The customary procedure, therefore, was to pack the orbital module with trash so that it would be burned up as well.

Bodies were not trash, of course, but burning them up in the atmosphere seemed as good a way as any to dispose of them—the space-age equivalent of a Viking funeral.

The normal up/down cycle of launch and reentry had, of course, been suspended. Things were supposed to go up, but not come down. Those orbital modules could be preserved and used as habitats, or for storing supplies. The “trash” could be picked over and used again. Bags of fecal material could become fertilizer in hydroponic farms.

Ivy made a unilateral decision that they would carve out an exception to that new policy. The deceased were moved into an empty orbital module docked at the truss. This was left open to space, so that freeze-drying of the bodies could happen out of sight and out of mind. When it filled up with dead people, they would have some kind of ceremony, the thing would be deorbited, and they would watch in silence as it drew a white-hot streak across the atmosphere below.

But it wasn’t full quite yet.

They had eight working Scouts until such time as another heavy-lift rocket could be prepared and sent up with a fresh half dozen. These worked in fifteen-, sometimes eighteen-hour shifts divided into three-hour phases. Each of those phases consisted of two hours’ actual work followed by an hour of resting in situ, or, using the obvious anagram, in suit.

Dinah, working in her robot shop, didn’t have a direct view of what they were doing, since her window faced away from the truss where they spent all of their time. She could watch their activities on video feeds if she wanted, but she had other things she needed to be doing.

After the micrometeoroid/Luk incident, Dinah had scored a small victory for robotdom by putting her flock to work getting the surviving Luks squared away. Amalthea was attached to the forward end of Izzy, which, because of its orbital direction, was most exposed to impacts from space junk. In effect the asteroid had been put there as a sort of battering ram, protecting everything aft of it from collisions. There was enough space on its aft side that several Luks could nestle there, improving their odds of long-term survival as well as cutting down on cosmic ray exposure.

Dinah’s crew of iron-mining robots had been made obsolete, at least for the time being, by her boss’s pivot toward frozen water. So, when not making tiny critters scurry around on slabs of contraband ice, she had made the older robots useful by getting them to drill holes and anchor some connection points—eye bolts, basically—into Amalthea’s back side and then moor the Luks to them using cables. This was not a hard-and-fast mooring system, so at first they tended to drift around and lazily bump into each other like a string of balloons. But after a day or two they settled into a stable configuration that just happened to block Dinah’s view out her window. All she could see now was plastic. She didn’t mind. After seeing the risks that the Scouts were taking, she didn’t mind anything at all.

Individual layers of the Luk were fairly transparent, but the view was gauzy because the layers were so many. She could make out the form of her neighbor’s body but not see the face. It was definitely a woman.

The Scouts’ shifts overlapped around the clock. The woman outside Dinah’s window came back in from her shift every day around what for Dinah was the middle of the morning. Dinah could see her clambering laboriously along the surface of Amalthea, using the mooring points, planning each move, avoiding the cables and the umbilicals. She must have been exhausted beyond words. Dinah had once done a two-hour stint in a space suit and been wiped out for a day. Sometimes Dinah would send a Grabb or a Siwi out to afford the woman an extra handhold when it looked like she needed one. The woman would turn her head and look at Dinah through the glass dome of her helmet and blink her eyes in what Dinah took to be an expression of gratitude. Eventually she would reach the open portal of her Vestibyul and go back into it, whereupon (unseen by Dinah) the automatic mechanism would do its thing, locking her suit into its socket, equalizing the pressure, opening the door, and enabling her to extract her head, arms, and body. Finding the ratchet wrench floating at the end of its chain of plastic zip ties, the woman would reach “above” her head and remove the twenty-four bolts securing the Luk diaphragm onto its flange, carefully rethreading each bolt into its hole so that it wouldn’t drift around loose, and then she would finally pull herself through the forty-centimeter portal into the comparatively spacious environment of the Luk. Along the way she would collect her “mail,” which was deposited in each Vestibyul during the occupant’s shift. This consisted of food; drink; toiletries; a bag of ice that would turn into water, providing a simple temperature-control scheme; bags for disposal of feces; and, in her case, tampons.

Because of the roundabout and improvised manner in which things were working now, Dinah did not have a way to communicate with this woman directly, or even to learn her name. This seemed ridiculous, but it was the same general phenomenon that had made it impossible for the firemen to talk to the police officers on 9/11. The Scouts were just using different radios with different frequencies, and Dinah didn’t have one.

By checking biographies on the NASA website, and by the process of elimination, she determined that this was Tekla Alekseyevna Ilyushina. She was a test pilot. She had competed in the most recent Olympics as a heptathlete and taken a bronze medal. As such she might have had glorious career options as a propaganda idol during the old Soviet days. But the recent conservative drift of Russian culture had left few slots available for women in male-dominated professions such as the military or the space program. Consequently much of her work experience had been outside of Russia, working for privately funded aerospace companies. She had returned a few years ago to become one of two active female cosmonauts. Dinah was cynical enough to see politics as the basis of that; in order for Roskosmos to remain on speaking terms with NASA and the European Space Agency, they had to have at least one or two females qualified to go into space.

Tekla was thirty-one. She had been somewhat glammed up for her official cosmonaut photograph, with a stiff, outmoded Princess Di hairdo that didn’t suit her at all. During the most recent Olympics she had been rated one of the fifty hottest female athletes by a click-bait website, but she was buried in the back of the rankings. Dinah thought her comely, with the high cheekbones, the green eyes, the blond hair, and all the other attributes one would expect of a Slavic superwoman. But she understood why Tekla had been rated number forty-eight out of fifty, for she had a kind of chilly, strong-jawed look about her that forced the makers of the website to be selective about camera angles, and, Dinah suspected, to make some use of Photoshop. The sort of men who would browse that kind of website would find Tekla off-putting in a way they couldn’t quite put their finger on. They would be intimidated by the taut cords of her deltoids during the shot put competition. Dinah made a point of not reading any of the comment threads. She already knew what those would say.

Tekla had been sent up here to die, and she probably knew it.

At the end of each shift when she squirted through the flange to float free in the milky plastic bubble of the Luk, she would peel off the fluid cooling garment that she wore against her skin all day long. This was made of stretchy blue mesh with plastic tubing stitched between its layers. It had no effect until it was plugged into a pump that circulated cool water through the tubes. Tekla must have hated it after sixteen hours, and so it came off first. Then, peeling her underwear down to her knees, she would deflate and remove the foley catheter that had been draining her bladder while she’d been at work. She would wipe herself down with premoistened towelettes that had been provided in her “mail,” and stuff those into a refuse bag. It appeared that she had shaved her head, or simply given herself a buzz cut, prior to leaving Earth, so she didn’t have to mess with hair. Only then would Tekla open up her packet of emergency rations and begin to eat. This often led to defecation, which she had to handle in the crudest way possible, with a plastic bag and another series of premoistened towelettes. All of it went into her refuse bag, which she deposited in her Vestibyul for collection during her next shift. Then Tekla would turn off the white LED strip that provided the Luk’s only illumination, and sometimes spend a little while gazing at the screen of a tablet computer before sliding a blindfold over her eyes and falling asleep.

Izzy circled the Earth every ninety-two minutes, passing through a complete day/night cycle each time, and so half the time that Tekla was asleep Dinah could look right out her window and see her suspended there, all but naked, floating in the Luk like a fetus in its bubble of amniotic fluid.

Dinah watched Tekla go through this routine for about a week, and found it all inordinately distracting. She brought Ivy, and later Rhys, into the chop shop to behold the sleeping Tekla through the window. They talked of Tekla and emailed each other pictures of Tekla that they had dug up on the Internet.

“That could be you or me, honey,” Dinah said to Ivy.

“It is us,” Ivy said, “it’s just a matter of degree.”

“Do you think we’re going to end up like that?”

Ivy thought about it, shook her head. “Look, the way she’s living isn’t sustainable.”

“You think it’s a suicide mission?”

“I think it’s a gulag,” Ivy said, “a little gulag right outside your window.”

“You think she’s in some kind of trouble?”

“I think we’re all in some kind of trouble,” Ivy reminded her.

“Oh yeah, I forgot.”

“She’s lucky, remember?” Meaning that Tekla had at least found a way off the planet.

“She doesn’t look lucky,” Dinah said. “I’ve never seen anyone so isolated. Does she talk to someone on that tablet? Or is she just surfing?”

“I can ask Spencer, if you want,” Ivy said. “I’m sure he’s logging all the packets.”

Dinah knew that Ivy was only kidding, but she answered, “Nah. She deserves that much privacy at least.”

Rhys’s reaction was to become aroused. He was reasonably discreet about it. But the elapsed time between his seeing Tekla and having sex with Dinah was, generously estimating, perhaps half an hour. Not that Rhys really needed a lot of help to start his motor. And not that Dinah did either. She had always known they were going to do it.

She had known this based on the way he smelled, at least when he was not in the middle of being sick. In other times and places, the way he smelled would not have been enough. They’d have dated first, or something. There’d have been complications having to do with existing relationships, incompatible lifestyles, fraternization policies. But here it was just automatic. And it was tremendous.

Based on what she was hearing from Internet buzz from the ground, it was also pretty universal. The human race might be about to disappear, but not before putting on a two-year frenzy of recreational sex.

Actually sleeping together was another matter. Rhys didn’t seem to mind it in principle. But it was difficult logistically. Astronauts generally slept in bags that kept them from floating about at random while they were unconscious. The bags were designed for one person. NASA hadn’t gotten around to manufacturing two-person bags yet, so if they felt drowsy afterward, they would improvise, swaddling themselves together with whatever they could cobble up. But it never lasted more than a few minutes. Then he would go back to his duties, and if she felt like a nap, she would climb into a bag that she kept in her shop, sometimes peeking out the window, guiltily, at poor Tekla.

One day, after Tekla had left for work, Dinah took one of the chocolate bars she had brought up from Earth, wrote her email address on the wrapper, and handed it off to a Grabb, which she then put out the airlock. She piloted the Grabb across Amalthea’s surface to the mooring point where Tekla’s Vestibyul was cabled in place, then made it climb along the cable (which was easy, it had an algorithm for that) and clamber into the Vestibyul, where it took up position and waited, holding the chocolate bar out in a free claw.

When Tekla came back at the end of her shift, Dinah got the satisfaction of watching her unwrap the bar and eat the chocolate. She held up one hand and sort of waved through the plastic. Dinah couldn’t resolve her facial expression.

The Grabb was still in the Vestibyul, and would remain trapped there until Tekla’s next departure. Seeing Tekla float over in that direction, Dinah turned to her computer and switched on the video feed from the Grabb. She was fascinated to see Tekla’s face, clearly resolved, float into the frame.

She didn’t look that bad. Dinah had been expecting someone who looked like a concentration camp survivor. But she appeared to be getting enough food.

Of course, she could not see Dinah. And there was no audio hookup. Since there was no sound in a vacuum, space robots didn’t come with microphones or speakers.

Tekla was just staring at the Grabb, impassive, perhaps wondering whether it could see her.

Dinah slipped her hand into the data glove, did the thing that made it connect to the Grabb’s free claw, and waved.

Tekla’s green eyes flicked down in their sockets as she observed this. Still no emotion.

Dinah was mildly offended. Was the Grabb not adorably cute, in its ugly mechanical way? Was the wave not an amusing gesture?

Tekla held up the candy bar wrapper. On it, beneath Dinah’s email address, she had written NO EMAIL.

What did that mean? That she lacked an email address? That her tablet couldn’t receive it?

Or was she imploring Dinah not to communicate with her that way?

The Grabb had a headlamp, a high-powered white LED that she could switch on by hitting a key on her keyboard. Dinah turned it on, saw the glow on Tekla’s face, the highlights on the lenses of her eyes.

Did the Russians even use the same Morse code as Americans?

Tekla had to know it. She was a pilot.

Dinah made the light flash with the dots and dashes for M O R S E.

Tekla nodded, and Dinah could see her mouth making the word “Da.”

Dinah signaled:

DO YOU NEED ANYTHING?

The faintest trace of a smile came over Tekla’s lips. It was not a warm kind of smile. More bemused.

She held up what was left of the chocolate bar, and pointed to it.

Dinah returned:

TOMORROW

Tekla nodded. Then she turned away, her buzz-cut blond hair glinting in the light of the LEDs, and drifted back into the middle of her onion.

“FIVE PERCENT” WAS HOW IVY BEGAN THE NEXT MEETING IN THE Banana.

It was full to capacity: the original twelve-person crew of Izzy, the five who had come up on the Soyuz on A+0.17, and Igor, the Scout who had come in from the cold when his suit had failed. He, Marco, and Jibran had prepped for the meeting by jury-rigging some fans to blow more air through the space, so it wouldn’t fill up with carbon dioxide. This had prompted Dinah to joke that perhaps all meetings should take place in hermetically sealed rooms, so that they could only go on for so long. No one, with the possible exception of Rhys, had seen it as funny. Anyway, the roar of ventilation was even louder than it usually was in space, and so Ivy had to speak up and use her Big Boss Voice.

“This is Day Thirty-Seven,” Ivy went on. “That’s ten percent of a year. If it’s true that we had two years from Zero to the Hard Rain, then we have already burned through five percent of the time during which we can expect to receive any help from Earth. Five percent of the time needed to turn this installation into a society and an ecosystem that is sustainable indefinitely.”

Ivy was standing with her back to the big screen, so she couldn’t see the reaction of the Arkitects down below, in some conference room at the other end of the video link. For today’s meeting, there were three of them: Scott “Sparky” Spalding, who was still the administrator of NASA; Dr. Pete Starling, the president’s science advisor; and Ulrika Ek, a Swedish woman who had worked as a project manager for one of the private commercial space startups until recent events had forced a career change: she was now coordinating the activities of several different space agencies and private companies as they worked on the Cloud Ark. Apparently, she had become the Arkitect-in-chief.

“Apparently” being the key word, since every time Dinah had any contact with the ground she was reminded of how little she understood of what was happening there. On one level she was one of the luckiest people in the human race. She was going to get to stay alive. At the same time, she and the others got very little information from the planet, and had to piece things together from a jumble of clues.

She’d compared notes on this with Ivy, who had confirmed that even she had little to go on, and what she did hear contradicted itself from hour to hour.

It had all become Kremlinology. Back in the heyday of the Soviet Union, the only way for Westerners to guess what was going on there was to look at the lineup of dignitaries on Lenin’s Tomb in the May Day parade, and riddle it out from the seating chart and who shook hands with whom. Now Dinah was doing the same thing with these three faces on the screen. Sparky was no use. He’d spent so much time in space that he had developed a kind of thousand-light-year stare. He was famous for being oblivious to the political side of things.

His opposite in that respect was Pete Starling. Pete’s job was to mutter scientific explanations into the president’s ear. He’d been doing rather a lot of it in the last thirty-seven days. He had a background running big science programs at universities, climbing the ladder from Mankato State to Georgia Tech to Columbia to Harvard in a mere ten years. Why was he sitting in on this meeting? There was little he could contribute. He must be here as the eyes and ears of J.B.F.

But why should J.B.F. care? No decisions were going to be made here; it was just a status report, a check-in.

As soon as Ivy finished her sentence, the corners of Pete’s mouth turned down. He looked at Ulrika Ek, a somewhat matronly woman in her late forties, extremely good at her job, according to Rhys. On the high-def video feed, Dinah saw the slightest deflection of her eyes, noticing the turn of Pete Starling’s head, but not exactly acknowledging it.

Ulrika clearly didn’t like him. But there was a reason she was a well-regarded project manager. “Ivy,” she said, “just for clarity, when we speak of ‘this installation’ we’re using the term in an elastic sense. Of necessity.”

Ivy turned to look at the screen. “‘Installation’ probably isn’t the right word,” she admitted. “Since it’s not installed anywhere.”

Pete Starling spoke up. “I believe that where Ulrika is going is that the Cloud Ark is a fluid concept that may paradigm-shift beyond recognition as we proceed adaptively through the next ninety-five percent of the timeline.”

Ivy’s brow furrowed. Something was going on, some kind of political tussle down on the ground. It was important to people like Pete.

“This is not efficient use of time,” Fyodor said. “I am working to extend truss to receive Pioneers.” Fyodor’s English was excellent, but when he was annoyed, as he was now, he dropped his articles. “I have eight suits outside, five inside, for unlucky number of thirteen.”

It had become common to use a form of synecdoche in which “suit” denoted “a person qualified to perform extravehicular activities who is equipped with a space suit that still works.”

“Pioneers arrive in two weeks, this is still true? Then I need more Scouts yesterday, as saying goes.”

When Fyodor had come up to Izzy six months ago, it had been understood as a valedictory mission before getting shunted to an administrator’s job at Roskosmos. Not that he hadn’t taken his duties seriously, but he always seemed to be taking the long view, perceiving Izzy through the eyes of a future bureaucrat who would need to make it run smoothly until his retirement. That had all changed on Zero, of course. It had changed even more with the Russian invasion. No new rank or title had been bestowed on Fyodor. None was needed. All the Russians just accepted him, implicitly and without question, as their leader. And his manner had changed accordingly. He was scrupulously respectful of Ivy’s authority, but there was no question that he was the boss of all things suit related, and the authority had seemed to make him physically larger and more imposing, his creased face tougher, his voice firmer.

Sparky answered him. “Fyodor, that fuel pump has been fixed. It was just a bad sensor. So the launch is going up as scheduled …” He checked his wristwatch, did a mental calculation. “Fourteen hours from now. Six hours after that, you’ll have your suits.”

“And the Zavods, the Vestibyuls—the things I mentioned.”

“We have had teams of engineers working on those fixes around the clock, Fyodor.”

“I am very worried about door closing mechanisms.”

THE REMAINDER OF THE MEETING HAD TO DO WITH THE PIONEERS who would start coming up in another two weeks, and who would live, for the time being, in rigid or inflatable habitats more accommodating than Luks. These would be docked along a series of pressurized tubes, little different in principle from the big spiral-wound ventilation ducts seen in warehouses, that would ramify outward from attachment points in the truss. Little of it concerned Dinah and so her attention drifted to her laptop. She had other things she could be working on, and Ivy’s reminder about the 5 percent had not left her in a mood to woolgather during a long meeting.

Most of her work of late had been on ice crawlers. And, as of the most recent shipment, ice tunnelers. But she had resolved that she would not shut down her progress on the iron-mining robots. Even if she only spent fifteen minutes a day on them, it was better than suspending work altogether. She was afraid that if she ever did that the entire project would disappear.

To that end, she kept a window open in the lower left corner of her screen, showing video from Amalthea, mostly the point-of-view cameras of robots that were actually doing things. It was always there in her peripheral vision as she attended to email and scheduling spreadsheets and Gantt charts.

And at some point she noticed something that wasn’t quite right. A few minutes later, she noticed it again and put her other work on hold. She expanded the window and took control of the robot that was transmitting the video. She swiveled its camera around until she had a view of the thing that had been bothering her.

It was Tekla, floating in her Luk. She was bright blue, which meant that she had donned her cooling garment. That was normal. She did it every day as she got ready for her shift. The next step should have been to squirm feetfirst through the Luk’s flange into the Vestibyul. But she wasn’t doing that. She was going back and forth between the Vestibyul and the middle of the Luk. She would go through the flange headfirst (which was abnormal) and do something for a minute or two, then withdraw into the Luk and thumb away on her tablet for a while.

She was late. Every other day, she’d been in her suit and out on the truss by this time.

Dinah wasn’t the only person who had become distracted by her laptop. Fyodor—normally not a fan of email and other such modern diversions—was watching his screen too, occasionally making eye contact with the equally distracted Maxim, who kept making a gesture like tugging at an imaginary beard.

Something was wrong.

What had Fyodor said? I am very worried about door closing mechanisms.

He wasn’t just saying that in the abstract. He was referring to a specific situation. He was talking about Tekla.

Tekla could clamber from her Luk, through the Vestibyul, and into her suit, but she couldn’t close the door behind her back. She needed the mechanism for that. If it didn’t work, then she couldn’t seal the suit. And if the suit wasn’t sealed, she was trapped inside her OVL (as they had taken to calling the combination of the Orlan suit with the Vestibyul and the Luk).

It was not exactly an emergency, but it was bad. In order to get “mail” she had to detach her suit from the Vestibyul, leaving it open for the delivery to be made in her absence. “Mail” included food, water, ice, and fresh CO₂ scrubber canisters.

Dinah didn’t know how long Tekla could survive without “mail,” but she doubted it was more than a day. The heat would get her first.

They had to figure out some way to get Tekla inside Izzy. And since the OVL was jury-rigged, it didn’t have a docking port like a normal spacecraft. There was no hatch, no way of mating to an airlock.

She studied Fyodor’s face through the rest of the meeting, which went on for another half hour, and began to understand something: he was getting ready to sacrifice Tekla. “Ready” in the sense of emotionally hardening himself to that reality.

Dinah understood NO EMAIL now. It was simply part of being a Scout that you would probably not survive. And if you knew you were going to be sacrificed, it wouldn’t help matters to be spamming the Scout email list with pleas for help and goodbye messages. Tekla could communicate with Fyodor, and Fyodor only, and that was for a reason. It was a reason that the defenders of Leningrad, Stalingrad, and Moscow would have understood and accepted perfectly well. But it was a little bit out of step with the modern ethos.

Correction: with the modern ethos as it had existed during the Age of the One Moon.

It was perfectly in step with how things were now.

Part of her wanted to go and plead with Fyodor to mount a dramatic and heroic rescue mission. There had to be a way to make it happen. They had all seen Apollo 13, they quoted lines of dialogue from it all the time.

But she already knew the answer. The Pioneers would begin arriving, shiploads of them, in two weeks. All of them would die on arrival if the correct preparations had not been made. No time could be spared. More Scouts were on the way to replace Tekla.

And for once she was glad that the meeting ran long, that Sparky didn’t stick to the agenda, and that Pete Starling exploited it to fill time with more buzzwords. Because an idea was slowly taking shape in her head. She would have to run it by Ivy and Rhys and perhaps Marco, she would want to have Margie Coghlan—the closest thing they had to a doctor—standing by, but she could do it with no help at all from Fyodor or any of the other suits.

Fyodor was typing something with his index fingers. She locked her eyes on his face and kept them there until he was finished. He seemed to have detected her gaze on him, because he then looked up and stared straight into her eyes, maintaining a perfect poker face.

She stared back.

Awareness crept into Fyodor’s expression. Awareness that Dinah knew about the problem. Fyodor knew the layout of Izzy better than anyone. He knew where Dinah spent her time, and that Dinah only had to look out her window to see what was going on. She could see him putting this all together in his head.

He was expecting her to make some emotional appeal. So, it was important for her to stay cool. As soon as she turned on the waterworks, she would lose his respect, and his attention, forever.

“Fyodor,” she said, “I got this.”

He blinked in surprise, then, after some hesitation, made the tiniest of nods.

“Got what?” Pete Starling asked, over the video link. “Am I missing something?”

“No,” Dinah said. “We are just proceeding adaptively to leverage our core competencies.”

BASED ON STATS FROM THE 50 HOTTEST OLYMPIANS WEBSITE, IVY WAS a fairly close match for Tekla physically. Tekla was huskier, but Ivy was an inch taller. So, the first thing they did was to stuff Ivy into the small airlock that Dinah used for her robots. With her head tucked and her knees drawn up to her chest, she fit into it with room to spare. Dinah took a picture, then appended it to an email message with detailed instructions.

Spencer Grindstaff, who, as a young CIA contractor, had cut his teeth hacking into email systems operated by foreign governments, figured out a way to send email to Tekla’s tablet by wrapping it in an envelope that made it look like it came from Fyodor.

Dinah watched Tekla read that email. She looked up from the tablet toward the window, then turned her gaze toward the airlock. Until then, Dinah had worried that Tekla might be losing consciousness, since she hadn’t moved in several hours. She guessed that Tekla was trying to conserve oxygen and reduce thermogenesis by moving as little as possible.

Dinah zip-tied a high-powered LED light to the inner hatch of the airlock, then closed it. She opened the valve that dumped its air into space, allowing it to “fill up” with vacuum, and then actuated the lever—a simple mechanical linkage—that flipped the outer hatch open. She could see the white glow of the LED reflecting against the plastic of Tekla’s Luk bubble a few meters away, and she saw Tekla’s head turn as the light got her attention.

Several robots had to act in concert to move Tekla’s Luk bubble around until it was pressed against the airlock. This was a somewhat maddening process, like trying to grab an inflated balloon with a pair of needle-nosed pliers. Dinah had been trying to do it with Siwis—Sidewinders—of which she now had a dozen in operation. A Siwi could join head-to-tail with another Siwi to double its length, and the process could be repeated indefinitely to construct a sort of smart, instrumented tentacle. By planting the tail of one Siwi against Amalthea, and bolstering the connection by holding it down with a couple of anchored Grabbs, she was able to make another Siwi slither up the first one and connect to its head, which was projecting up into space. A third Siwi climbed up the first two and concatenated itself, and so on and so forth, building a stalk that reached up from the surface of the asteroid and began to curve around the bubble in which Tekla was imprisoned.

So far so good. But the longer the chain grew, the worse it behaved. The Siwis were constructed like caterpillars, consisting of many identical segments connected by flexible joints. The joints were motorized, and the motors were supposed to follow commands embedded in Dinah’s code, and it was all supposed to work in a predictable way. The problem was that each joint had a bit of flexibility, which as far as Dinah was concerned was error. Those errors accumulated as the length of the chain grew, so that by the time she had connected three Siwis together, she found it difficult to know, let alone control, the position of the end of the stalk. And when she tried to apply force by making the chain curve around the slippery, bulgy surface of the Luk, matters only got worse.

Rhys showed up a few hours into the project and watched. He’d be silent for hours, then suddenly ask a question that was strangely off-kilter and yet showed he was thinking about the problem.

“What if you turned all the motors off and let the whole thing go slack?” he asked.

“Aren’t you supposed to be building a torus?” she demanded, and turned around to give him her best attempt at a killing look.

“First we have to solve this problem,” he said gently.

She had more to say, but instead she went silent. Rhys was clowning around with his necklace again. He was in the habit of wearing a chain around his neck—nothing fancy or bulky, just a simple loop of twisted-link jewelry chain in stainless steel, which he used as a way to keep thumb drives and other important small objects from floating away. At the moment, though, he had removed all of that stuff, leaving the chain unencumbered, and he had got it spinning around his neck. It had opened up into a broad, undulating oval that didn’t touch his neck or collar anywhere, so it was just orbiting around him in free space. Dinah had seen him do this before, typically while bored in meetings. He had learned a few tricks for speeding it up and coaxing it into different shapes by blowing on it with a drinking straw or flicking it with a fingernail. It didn’t form a perfect circle, as one might expect. The moving train of links could be molded into almost any shape, and would stay that way until disturbed. When Dinah turned around and noticed he was doing it again, she was about to roll her eyes and say something like For fuck’s sake can’t you do anything useful with that brain, but the look on Rhys’s face suggested that he was up to something more than just playing around.

The chain had been running in an elongated racetrack shape, nearly buzzing his neck on one turn, but he flicked at the straightaways and broadened it into something approaching a circle, then ducked out of it, leaving the loop spinning in midair. “Channeling the wisdom of my ancestors, if you must know,” he said.

“You had ancestors in zero gee?”

“Alas, no. My great-great-great-great-uncle John Aitken was an eccentric Victorian meteorologist with an even more eccentric hobby: studying the physics of moving chains. Unfortunately for him, he had to do it in his drawing room in Falkirk, where there is, I’m sorry to say, gravity. He had to approximate this sort of thing”—Rhys nodded at the whirring loop of chain—“by building exceedingly clever machines.”

“Then he must have been a clever man indeed.”

“Fellow of the Royal Society and friend of Lord Kelvin, since you mentioned it. Do you see where I’m going?”

“Well, a minute ago you gave me a fat clue by suggesting that I turn off all of the motors in the Siwi train. Were I to do that, it would go completely limp and become, for all practical purposes, a length of chain.”

“Yes,” Rhys drawled, and poked an index finger up into the chain’s path. It caught on his knuckle, hiccupped, and suddenly wrapped around his hand in a chaotic tangle.

“That’s confidence-inspiring,” Dinah said.

“Hold on, it turns out my uncle John knew a few things. And later on, another chap, name of Kucharski, in Berlin, worked on this stuff too.” Rhys was untangling the chain, looking for its clasp. When he found it, he undid it, converting the chain from a loop into a segment about as long as his arm. “Unfortunately there’s gravity in Berlin too, so he had to do stuff like this on tables. Hold it right there, would you please?” And he got Dinah to pinch the middle of the chain between her fingers, keeping it fixed in space. From there, he drew the two ends back toward himself, forming the chain into a skinny, elongated U. “You can let go now, gently.”

Dinah released the chain and allowed herself to float back from it, since Rhys had taken on something of the air of a magician in performance. He let go of one of the ends, kept the other grasped between his thumb and index finger. “What happens if I pull?” he asked. “Any predictions?”

“The whole thing will move back toward you, I guess.”

“Let’s try it. Hold your finger up just there.”

Dinah pointed “up” and allowed Rhys to reach out with his free hand and grasp her gently by the wrist, arranging her hand so that the finger was several inches away from the vertex of the U-shaped bend in the chain. “Here goes nothing,” he said, and began to pull the chain toward him—away from Dinah. Contrary to what she’d expected, the bend started to propagate away from Rhys, and toward Dinah, until finally the free end hurtled around, like a whip cracking, and made several quick turns around her finger, snaring her. “Gotcha,” he said, and began pulling her toward him.

“Just like a bullwhip,” she observed, unwinding the chain from her finger too late to avoid being drawn into close, cozy contact with Rhys.

“It is exactly the same physics,” he confirmed. “Kucharski called that thing—the traveling U-shaped bend—a Knickstelle. It means something like ‘kink place.’”

“Chains, whips, and now kinks. I’m learning so much about your Victorian ancestors, Rhys.”

“You probably thought this was a mere diversion,” he said.

“Oh, no. I see your point. Rather than trying to control the Siwi chain, like a tentacle, all clenching muscles, let it relax and whip around the Luk like a smart chain.”

This little digression into nineteenth-century physics turned out to be one of those “one step back, five steps forward” sorts of trades. It was the work of a few minutes to concatenate four more Siwis onto the existing chain, then turn off all the motors except a few that she used to fashion a U-shaped bend. Applying tension to one end of it caused the Knickstelle to propagate just as in Rhys’s demonstration, so that the end of the chain whipped lazily around the entire circumference of the Luk. Several attempts were required before the grappler at the end of the chain was able to snag a handhold on the far side, but then the Luk was securely captured in the chain’s embrace. Grabbs could scuttle along it carrying the ends of cables anchored to other parts of Amalthea, or Izzy, and thus the Luk was gradually ensnared in a loose web of hardware that Dinah used to draw it away from the position where it had been anchored, and pull it up snug against the module containing Dinah’s shop. As it came closer, the vague nimbus of white light thrown against the Luk by the LED in the airlock narrowed and sharpened, and was finally all but snuffed out as the big balloon enveloped the protruding stub of the airlock chamber. The airlock was now poking into the nested layers of the Luk like a finger prodding a balloon.

Even after the success of the whip-cracking gambit, this took most of a day. Rhys drifted off, as was his habit. Bo, the Mongolian cosmonaut, slipped into Dinah’s shop, observed silently for a couple of hours, and then began finding ways to make herself useful. She learned how to use the data glove and the mouse-and-keyboard interface just by watching Dinah, and by the end of the day was piloting Grabbs around, and manipulating Siwis, like an old hand.

Margie Coghlan showed up to watch the final preparations. She was an Australian physiologist who had been sent up to Izzy a few months ago to study the effects of spaceflight on human health. Dinah had always found her a little brusque, but maybe that was just an Australian thing. She brought with her a box of medical supplies and surgical equipment. All the astronauts on the ISS had medical training. Dinah and Ivy had done their time working in Houston emergency rooms stitching up trauma victims and setting bones. But Margie was the best.

“Not exactly what you signed on for,” Dinah said.

“None of us is getting what we signed on for,” Margie observed.

“With the possible exception of Tekla,” said another voice. Ivy’s. She was not in Dinah’s shop—that was full now with Dinah, Bo, and Margie—but she was in the adjacent SCRUM.

“Ivy, you ready to set another record?” Dinah asked.

“Ready to try,” Ivy said.

This was Q code for the number of women on the space station at one time. The old record had been four, set in 2010. They had tied it months ago when Margie and Lina had come up to Izzy, joining Ivy and Dinah. They had broken it when Bo had turned up in the Soyuz launch three weeks ago. Tekla would make six, if they could only get her through the airlock.

Or the number might drop back if this went wrong.

“Bo, thanks for helping. You should probably go out with Ivy.”

“Good luck,” Bo said, and, pushing off from the inner hatch of the airlock, drifted across Dinah’s shop and out through the hatch into the SCRUM, where Ivy hovered, waiting.

“Everything sealed up behind you?” Dinah asked, more out of nervousness than anything else. It was out of the question that Ivy would get that wrong. Since the breakup of the moon, they’d intensified their precautions anyway, keeping the various modules of Izzy separated by airtight hatches wherever possible so that the perforation of one module by a bolide wouldn’t lead to the destruction of the whole complex.

Ivy didn’t answer.

“You know what to do with that hatch if this all goes sideways,” Dinah went on.

“You talk a lot when you’re nervous,” Ivy said.

“I concur,” Margie said. “Are we going to do this or not? That woman might be asphyxiating out there.”

“Okay. Giving her the signal now,” Dinah said.

In the space program that she had dreamed of when she’d been a little girl with a “Snoopy the Astronaut” poster on the ceiling of her shack in the hinterlands of South Africa, or watching live feeds from the space station on satellite TV in western Australia, the signal would have been a terse utterance into a microphone, or a message struck out on a keyboard. But what she actually did was drift over to her little window and peer through fourteen layers of milky translucent plastic at Tekla, almost close enough to reach out and touch, and give a thumbs-up.

Tekla nodded and held up a small object next to her head. It was a folding knife with a belt clip and a lanyard, which she had prudently wrapped around her wrist. Using one thumb she snapped its serrated blade open.

Dinah nodded.

Tekla nodded back, then drifted out of view, headed toward the airlock.

“Here she comes,” Dinah said.

She had already sized Margie up as a woman of some physical strength. She was stocky, but in a powerful rather than a flabby way.

Dinah got a grip on the mechanical linkage that would swing the outer hatch of the airlock closed. “Brace me,” she said.

She was worried about all that plastic. Shreds of it were certain to get caught in the hatch’s delicate seal.

The principle was simple enough. She’d run through it in her head a hundred times. If Tekla cut a slit, a few inches long, through the innermost layer of the Luk, air would rush out into the space between it and the next layer, which was at a lower pressure. If Tekla put her head and shoulder into that slit, she’d become like a cork in a champagne bottle, and the pressure would try to force her out. If she then cut a slit through the next layer, and the next, and the next, a wave of pressure would build up behind her and spit her out like a watermelon seed. And as long as she kept aiming for the white LED on the airlock’s inner hatch, she would be projected into that airlock.

At that point she’d be naked and unprotected in the middle of a jet of air that would be exploding away from her into the vacuum. And at that point—

There was a whoosh and a meaty thunking impact.

“Jesus Christ, I think that was it,” Margie said.

“She is out,” Bo confirmed. Bo, out in the next compartment, had a tablet on which she was watching a video feed from a nearby Grabb. “I mean she is in the airlock.”

Dinah hauled on the handle, swinging the outer hatch closed. Her body, in accordance with Newton’s Third Law, moved in the opposite direction, stealing her force, but Margie’s arms caught her in a bear hug and pushed back—Margie had found a way to brace herself.

Bo gasped. “You are smashing her foot!”

“Oh, shit.”

“Her foot is sticking out.”

“Dinah,” Ivy said, “you have to open the hatch a little, her foot’s caught.”

Dinah relaxed her arms. What if Tekla was unconscious? What if she was unable to draw herself up into the fetal position they’d shown her in that photograph?

The change in Bo’s and Ivy’s tone told her otherwise. “She’s in!” Ivy exclaimed.

“Close the hatch, close it!” Bo was shouting.

Dinah swung the handle all the way around and snapped it into its locked position. It didn’t feel quite right, but at least it was closed.

Meanwhile Margie was actuating the valve that let air into the airlock. This was supposed to be a gradual process, but she just let it go explosively, with a sudden movement of the air that tugged at their diaphragms and popped their ears.

“Blood is coming out,” Bo said dully. “Leaking out of the hatch.”

“Fuck!” Dinah said. Because that meant two bad things at once: the outer hatch wasn’t really closed, and Tekla was hurt.

“Let’s get it open,” Margie said.

In the end it took all four of them: Dinah, Margie, Bo, and Ivy, all crammed into the space with their fingers under the rim of the hatch, pushing against the wall with all the strength in their legs and their backs, to break the seal. Whereupon air whooshed out of the compartment and the hatch flew open, like when you finally break the seal on a vacuum-packed jar and the lid flies off.

Tekla was in there, drawn up into the prescribed fetal position, a solid mass of red.

They all stared at her speechless for a moment.

Her head moved. She turned her face up toward them, revealing a huge red smear where an eye ought to have been.

The only thing that kept Dinah from screaming like a little girl was her gorge rising up into her throat. Bo drew in a long breath and began muttering something.

Tekla’s hands unfolded and gripped the rim of the chamber. The lanyard of the knife was still wound around her right wrist. The handle of the knife trailed after it. Dinah supposed that its blade had been snapped off until she understood that the whole thing had become embedded in Tekla’s forearm.

Tekla pulled herself out a few inches, then stopped. Her head was now projecting into the room.

An eye opened. A bloodshot eye in a bloody face. But a normal, working eye.

Dinah’s ears began working again and she realized that she was hearing a loud hissing noise. It was the sound of air escaping from the International Space Station, not through a huge leak but through small gaps in the airlock’s outer seal. The air was flowing past Tekla’s body, creating a vacuum behind her, a vacuum she had to fight in order to advance into the room.

She felt embarrassed then, in the manner of a hostess who forgets to properly welcome a guest, and she reached down and grabbed one of Tekla’s hands. Margie got the other and with a final sucking, squelching noise they dragged Tekla’s blood-lubricated form out of the airlock chamber and into the space station.

Dinah half closed the inner hatch of the airlock. The Big Hoover, as old-school astronauts referred to the vacuum of space, took care of the rest, and slammed it closed with frightening violence.

They’d lost a measurable percentage of the atmosphere in this module. Not enough to cause oxygen deprivation but more than enough to set off alarms all over Izzy, and all the way down to Houston.

Maggie got to work on Tekla’s arm, which was bleeding quite a lot, while Ivy and Bo, now blue-gloved, cleaned off her face with towelettes. The picture was getting clearer. The basic idea had worked. Tekla’s knife work had been true and well aimed, and perhaps more effective than was really good for her. She had been spat out of the Luk’s outermost layer, and into the airlock chamber, with great force, slamming her face into a metal fitting along the way and opening up big lacerations above and below the eye. These had bled profusely. In the same moment the blade of her knife had caught on something and turned back on her and been jammed into her forearm. She had lain dazed for a moment, one leg hanging out the open hatch as Dinah had tried to close it on her, then had come to and drawn herself up as planned. For a few moments during all of this she had been exposed to vacuum, which hadn’t done her bleeding wounds any favors, but air had rushed into the lock and equalized the pressure before irreparable damage could be inflicted.

As Dinah had worried, scraps of plastic had gotten caught in the outer hatch’s gasket, accounting for those hissing air leaks. But most of them drifted off into space when she swung the hatch back open again, and the remaining bits, stuck to the gasket by Tekla’s freeze-dried blood, she was able to pick clean using a programmed swarm of Nats. She ended up leaving that project as an exercise for Bo, who was climbing the robot learning curve with remarkable speed.

She drifted down the length of Izzy to the Hub and thence out to the torus, where Maggie, getting advice from trauma surgeons down in Houston, was working on Tekla’s arm. This was a lot easier in the weak gravity of the torus—no globules of blood drifting around. Lina Ferreira and Jun Ueda, both also life scientists, were filling in as assistants.

Ivy was in her office fielding a shit storm of angry reaction from people down in Houston.

They were doing the surgery under local anesthesia, so Tekla was awake. They’d cleaned her up, and closed the lacerations around her eye socket with butterfly bandages and Krazy Glue. The silvery-blond stubble that covered her scalp was still darkened with coagulated blood along that side. The whites of her eyes were red, and she had thousands of tiny red marks all over her face. Dinah had been warned to expect those. They were called petechiae: broken capillaries just under the skin, caused by exposure to vacuum. But from the way her eyes moved in their sockets and focused on things, Dinah could see that her vision was basically intact.

“That was uncalled for,” Tekla said to her.

“True,” Dinah said.

“I shall be in trouble.”

“So are we,” Dinah said, nodding in the direction of Ivy’s office. “We are all in trouble … with a bunch of dead people.”

Tekla reacted very little, but among Margie and Lina and Jun there was a collective intake of breath, a momentary halt in the proceedings.

“Margie,” said a Texan voice from the ground, “this dead surgeon would like you to clamp off that arteriole before it starts bleedin’ again.”

“Those of us who are going to live,” Dinah said, “have to start living by our own lights.”