Seveneves
In theory it was all just a big computer program that, when executed, would smoothly convert the solid hill of ice into something like a walnut with the meat removed: a thick, pockmarked outer shell with an organic internal system of ribs, veins, and webs. As with any other computer program, it might run perfectly when Dinah started it. But it might just as well go sideways, perhaps in a manner that wasn’t obvious at first. So situational awareness was going to be a big part of her task. Interesting as it might be to look out the window and watch the Earth screaming by at twenty-four thousand miles per hour, she would need to keep her head down, searching through a roar of weak and ambiguous signals for signs that something was going awry. She liked to imagine that her days as a little girl in a mining camp, sitting in front of a radio console trying to pick out Morse code signals from far away, through static and crosstalk, might have prepared her for it in some way.
A FEW MINUTES INTO HIS SCAPE CONVERSATION WITH J.B.F., DOOB realized that, two years ago, he had done his job too well.
He’d gone into that meeting at Camp David with the mission of getting the president to understand the exponential breakup of the moon that was going to wipe out life on the Earth’s surface. Putting on his Doc Dubois hat, he had coined the terms White Sky and Hard Rain as easy-to-grasp handles on phenomena that, truth be told, were much more complicated. Dr. Harris was now wishing that the late Doc Dubois had never opened his big fat mouth.
He was in a corner of the Farm that, since the departure of New Caird, had developed into a sort of bullpen where he and Konrad and some of the other orbital mechanics geeks hung out. The Farm had always operated something like a high school cafeteria, with different cliques habitually sitting in certain areas, and now those choices were hardening, becoming a part of Izzy’s unwritten procedure manual. Anyway, they had printed out charts and plots representing, in more or less abstract form, everything that they knew about the ongoing development of the lunar debris cloud and what it might mean for the future of the Cloud Ark. The expenditure of paper and printer ink had been somewhat lavish. Two generations from now, if any humans survived, they would look on this heap of documents with some combination of disgust and amazement. Because paper was going to be scarce by then, and they would view its use for such purposes in roughly the same way as Americans of the twenty-first century had viewed the use of sperm whale oil to fuel streetlamps.
But then life would get better, forests of genetically engineered trees would grow in vast rotating space colonies, paper would become plentiful, and these sad yellowed scraps would be displayed in a museum as evidence of the privations suffered by the Arkers.
Assuming they didn’t screw it up. Which was really the topic of this Scape call with Julia. She was floating in her arklet. She seemed to have adjusted to zero gee; she’d figured out how to pull her hair close to her head, the moon face had abated, she wasn’t visibly nauseated. People were drifting to and fro in the background. The only one Doob recognized was Camila. A couple of other kids were doing what looked like work: prodding and massaging their tablets purposefully, looking up from time to time to engage in brief conversations. A South Asian lad, an African girl, another girl who was probably Chinese.
Girl, kid, lad, girl. His politically correct superego, cultivated during long years of service in academia, was trying to light up his shame neurons. Doob felt no shame—he was way past that—but he was struck by just how young the Arkies were, how different they were demographically from the General Population. It gave him a vaguely troubling sense of being out of touch. It had been decades since he had been young, but he had always been one of the cool kids anyway, with a big following on Facebook and Twitter. Now he was stuck on Izzy and Julia was stuck in an arklet. The two of them were hanging out with completely different populations. GPoppers saw each other all the time and talked face-to-face. Arkies were isolated in their arklets and had to use social media to reach out. Doob hadn’t looked at his Spacebook page since the White Sky, and this call with Julia had been delayed for fifteen minutes while he’d tried to figure out the user interface on Scape—something with which Julia was obviously familiar and comfortable. She used it all the time, and if it didn’t work, one of those kids in the background would help her with it.
Another straw in the wind: while Doob had been fumbling with Scape, he had overheard a brief snatch of conversation from the other end in which the South Asian kid had addressed Julia as “Madam President.” This seemed so odd that he was tempted to bring it up in conversation. But he knew what the answer would be: It was just a courtesy. Former presidents were always addressed thus. It didn’t mean anything. Why was he making a big deal about it? He would come off as some combination of uncouth and comically hypersensitive.
“Dr. Harris, as you know, I’m something of a fifth wheel around here, and so I want you to know I appreciate your taking any time at all out of whatever it is you are busy with to touch base,” Julia began.
“Not at all, Madam . . . Julia,” Doob said, and then, because this was a video connection, resisted the urge to slap himself.
She found that interesting but decided to overlook it. “I feel like a camp counselor here,” she said. “Of course, I was on top of every detail of the Arkitects’ work during the run-up. But to sit in the White House looking at PowerPoints is one thing. Actually to be here is quite another.”
This was quite obviously bait. Fully aware of what a sucker he was being, Doob said, “How so?”
“Well, of course the range of cultural perspectives is vast,” Julia said, “but, modulo that, I find a lot of uncertainty. A sense that all of the Arkies’ talents and energies are bottled up—like so many genies just waiting for someone to rub the lantern. They all so keenly want to help.”
“It is, of course, less than two weeks since the Hard Rain began,” Doob pointed out. “We have five thousand or so years left to go.”
“The Arkie Community is well aware of those numbers,” Julia remarked.
The Arkie Community. Wow. He had to admire the way she’d slipped that in.
“Julia, what’s the purpose of this call? Am I to understand that whatever answers I give you will then be somehow disseminated to the Arkie Community? Because we have an email list for such purposes. An email list that includes every living human being.”
“That list was most recently used two days ago. An eternity for bottled-up Arkies.”
“We have been just a tad busy with the New Caird expedition.”
“There is a lot of curiosity about that in the Arkie Community.”
“There’s a lot of curiosity about it here.”
“I mean about its purpose,” Julia said.
“How could its purpose be any clearer?” Doob asked. “Anyone who made it through the screening and the training required to become an Arkie”—which doesn’t include you, Julia—“will understand exactly what we are trying to do from an orbital mechanics standpoint.”
“Obtain the stupendous amount of water that will have to be expended in order to attempt the Big Ride gambit,” Julia said. “Yes, Dr. Harris, even I understand that.”
“Gambit? Really?”
“Do representatives of the GPop ever make much of an effort to reach out and acquaint themselves with the thoughts and perceptions of the AC?” Julia asked.
“The what?”
“The Arkie Community,” Julia explained, with the slightest roll of her eyes.
“At any given time, about ten percent of the Arkies are rotating through Izzy. You know this. It is the largest number we can accommodate.”
“I’ve talked to several who have experienced that rotation. They all report the same thing. As soon as one enters the privileged environment of Izzy, with safer conditions, more room to move about, better food, and greater exposure to senior staff, the GPop worldview seems so sensible. Which only accentuates the reentry shock upon being deposited back into one’s arklet.”
Doob bit his tongue.
Julia co
ntinued. “What about reversing the roles a little—sending members of the GPop on temporary home stays in randomly selected arklets?”
“What about it?” Doob asked. “What purpose would it really serve?”
“From a purely technocratic standpoint, perhaps none whatsoever,” Julia said. And left the rest of her thought unsaid.
“If I went on a ‘home stay’ in a random arklet, what would I learn that I can’t learn from Scape or Spacebook?”
“A great deal, since you don’t actually use those applications,” said Julia, her voice deepening in amusement.
“I’m a little busy trying to get New Caird home. Go ahead, tell me. What am I missing?”
Movement caught his eye across the table.
He looked up to see Luisa shaking her head. Then Luisa clamped her face between her palms, closed her eyes for a moment, and opened them again. Doob felt his face warming, and once again resisted the temptation to slap himself.
“There is a lot of ferment in the AC around alternative strategies,” Julia said, speaking briskly and authoritatively, as befit a woman who had just been anointed the spokesperson for said Arkie Community. “A fascinating school of thought is developing around the idea of making a passage through clean space to Mars.”
“Clean space?”
“Oh, I forget you haven’t been following the relevant discussion groups. Clean space is just what Tav has been calling the translunar zone, relatively free of bolides.”
“Tav? Tavistock Prowse?”
“Yes, you should have a look at your old friend’s blog occasionally.”
Tav had been sent up to Izzy a month before the White Sky, when someone on the ground had decided that social media was going to be the glue that would hold the Cloud Ark together and that Tav was just the man for that sort of thing.
“I’ve been busy,” Doob said. “But Tav ought to know that we have simulated and war-gamed the Mars option to within an inch of its life, and it’s just not a good idea.” He could see Julia formulating an objection that he didn’t have the patience to listen to. “Anyone who is seriously advocating we go to Mars is—” He didn’t want to say what he was thinking, which was smoking crack, and so he settled for “—not taking some of the practical realities into account. One solar flare at the wrong time could kill everyone.”
“Only if everyone goes.”
“If you’re talking about just sending a contingent to Mars, then you have to consider how much of our equipment and supplies they’ll be allowed to take with them.”
“I think many talented Arkies would volunteer to be part of a small, lean advance party. The lure of clean space is strong.”
“Well, we are not in what I guess Tav considers clean space,” Doob said. “We are in dirty space, and we have to focus on that reality, rather than woolgathering about trips to the Red Planet.”
“You needn’t remind me,” Julia began.
“Yes. You saw your friend and colleague Pete Starling get chowdered by a bolide. I did actually see your Spacebook post about that, Julia. It was most affecting. I sense a ‘but’ coming, however.”
“As the days go by without a serious incident, people begin to wonder how dirty space really is. Interest grows in the Dump and Run option. The White Sky now feels like ancient history. The Hard Rain is upon us. Every day brings a course correction or two, to avoid a major bolide, and a litany of minor events. But the death toll stands at—”
“Eighteen, as of ten minutes ago,” Doob said. “We just lost Arklet 52. See, I am keeping my ear to the ground.”
“I am sorry to hear that,” Julia said, “and I’ll bet the rest of the AC will feel the same way, once that news has been distributed to them.”
“It’s on a fucking spreadsheet, Julia. All you have to do is look at it. We don’t distribute news. This is not the White House.”
“But in many respects it behaves like the White House,” Julia said. “An orbiting White House unfettered by constitutional checks and balances. But at least the White House had a briefing room, a way of reaching out. I would be happy to . . .”
“Why are you even talking to me about this?” Doob asked. “I’m a fucking astronomer.” Then, a thought. “How many conversations like this one have you been having with other members of the GPop?” He’d been assuming that Julia had singled him out as special, but for all he knew she had a call list as long as her arm, organized by those assiduous youngsters in the background. “Ivy is temporarily in charge.”
“I am familiar with the chain of command that has been improvised,” Julia returned. “To answer your question, Dr. Harris, I am talking to you precisely because you are an astronomer, and well positioned to answer the questions and concerns among the AC about the exact nature of the dirty space threat. This news from Arklet 52 is going to raise questions about the effectiveness of Ivy’s current strategy.”
“It is a statistical problem,” Doob said. “On about A+0.7 it stopped being a Newtonian mechanics problem and turned into statistics. It has been statistics ever since. And it all boils down to the distribution of bolide sizes, and of the orbits in which they are moving, and how those distributions are changing over time—which we can only know from observation and extrapolation. And you know what, Julia? Even if we had perfect knowledge of every single one of those statistical parameters, we still wouldn’t be able to predict the future. Because we have an n of 1. Only one Cloud Ark, only one Izzy to work with. We can’t run this experiment a thousand times to see the range of different outcomes. We can only run it once. The human mind has trouble with situations like that. We see patterns where they don’t exist, we find meaning in randomness. A minute ago you were casting doubt on whether dirty space was really that dirty at all—obviously arguing in favor of Dump and Run. Then I told you about what just happened to Arklet 52 and now you’re swinging around to the other point of view. You are not helping, Julia. You are not helping.”
Julia did not look to be accepting Doob’s remarks in the spirit intended. Instead she squinted through the screen at him and shook her head slightly. “I don’t understand the intensity of your reaction, Dr. Harris.”
“This conversation is over,” Doob said, and hung up on her. He then fought off a temptation to slam the tablet down on the table. Instead he sat back in his chair and looked Luisa in the eye for the first time in a while. On one level he’d wanted to watch her face the whole time. But Julia would have noticed that, would have figured out that someone else was in the room, silently listening.
Just as someone had probably been doing at Julia’s end.
Luisa just sat there in her listening shrink mode.
“It would be easier,” Doob said, “if I could figure out what the hell she wanted.”
“You’re assuming,” Luisa said, “that she has a plan. I doubt that she does. She is driven to seek power. She finds some way to do that and then backfills a rationalization for it afterward.”
Doob pulled his tablet closer and started trying to find Tav’s blog. “To what extent do you imagine she really is reporting facts about the AC? As opposed to creating the reality she describes?” Doob asked.
“What’s the difference?” Luisa asked.
DINAH LOOKED UP AND SAW THAT THE EARTH WAS THE SIZE OF A grapefruit. She took a nap, ate some food, and buckled down to work again, then looked up to see that it was the size of a basketball. Still not that big; and yet such was their speed that it was only an hour away.
They had a final briefing session in Ymir’s common room, which had become a makeshift bridge for this ungainly ship.
Dinah had scrounged three flat-panel monitors from various parts of the command module and zip-tied them to the common room table. These were covered with overlapping windows of various sizes. Some were terminal windows showing log entries or editors showing code, but most were video feeds showing different robots’ points of view on the mining operation. Only one of them looked outward: she’d positioned a redundant Siwi on the ste
rn, toward the nadir, and aimed its camera at Earth. Other than that, her only “situational awareness” would come from a celestial navigation program that would display, in a small window, a three-dimensional rendering of the Earth with Ymir’s trajectory superimposed on it as a geometric curve. Along the bottom of that window was a series of graphs plotting velocity and altitude versus time. Their velocity at the moment was some six thousand meters per second, up from four thousand just a couple of hours ago; within the next hour it would double if they took no action, then begin to drop again as they left perigee behind and coasted away into space.
That velocity would take them all the way back out to L1 again unless Jiro succeeded at his task, which was to slow them down. He had satisfied himself with but a single flat-panel screen, which he’d set up directly across the table from Dinah’s triptych. From here he would be managing the reactor. He had already begun to pull some of the control blades, just to get a sense of how quickly it would come to full power when he did it for real. A miscalculation on that front had led to the fuel rod breach that had indirectly killed Sean, and Jiro didn’t want any surprises this time around.
Some minutes before perigee, if Markus felt that things were otherwise going to plan, Jiro would issue commands that would bring the reactor up to its full thermal power output of about four gigawatts. Ice would melt to superheated water, and steam would howl through the Inconel throat of the nozzle, expanding and cooling in the bell until it turned into a hypersonic blizzard, a white lance of cold fire pushing against the great ship’s movement, slowing her down. Not so much as to let her fall into the atmosphere and die, but enough to reduce her orbit to something more like Izzy’s. Ymir would experience acceleration, which would feel to its inhabitants like gravity. All the stuff that was now floating around loose aboard Ymir and New Caird would fall “down.” Dinah and Jiro would drop into the chairs that they’d positioned in front of their monitors. So would Markus, for he had built his own nest of tablets and monitors at the head of the table, mostly occupied with navigational data. Up in New Caird, Slava would find himself pressed into his acceleration couch at an awkward sideways angle. The gee forces would be modest enough—even a four-gigawatt nuclear propulsion system could only exert so much force against the momentum of such a large chunk of ice. If their “weight” remained steady over time, it was a sign that things were going well. If it increased, it probably meant that they were going to die. For the only thing that could slow them down and increase their perceived weight beyond a certain level was contact with the atmosphere. The more they slowed down, the lower they dropped. The lower they dropped, the thicker the air got. The thicker the air got, the more force it exerted on the ship. They would read this as a sense of increased weight. It was an exponential spiral that, beyond a certain point, would lead to the inevitable destruction of Ymir, New Caird, and everyone on board. The only real question would be the manner of their death. In a smaller, lighter craft they might be burned alive. Here, being surrounded by ice, it was more likely that they would lose consciousness from the gee forces first—a relatively painless way to go. Dubois Harris and Konrad Barth, gazing down on them from a few hundred kilometers above, would see them go out as a blue streak over the southern hemisphere, and would give the news to Ivy so that she could issue a statement to the Cloud Ark that, if Dinah was any judge of her friend, she had already written, just in case she needed it.