Aurora

by Kim Stanley Robinson

  They went in the room containing that part of the pipes, and Aram applied the engineer’s solution, as they called it, tapping with a wrench the exposed curved jointed section that held the thermostat and valve regulator, which together seemed to be the source of the problem. Then he hit the joint itself with considerable force. With that a row of lights on the control panel turned from red to green, and the piping on both sides of the joint began to emit a soft flowing gurgle, like a flushed toilet.

  “The valve must have closed and then stuck,” Aram said with an unhumorous smile. “The swing around Planet H must have torqued it.”

  “Fuck,” Devi said, voice rich with disgust.

  “We need to test these things more often,” Delwin said.

  “Stuck by temperature or torque?” Devi asked.

  “Don’t know. We can look at it when we get the main system going again. By temperature do you mean hot or cold?”

  “Either. Although cold seems more likely. There’s condensation in all kinds of places now, and if some of it froze, it might make that valve stick. I think every criticality that is a moving part should be moved every week or so.”

  “Well, but that would be a wear in itself,” Aram said wearily. “The testing itself might break something. I want better monitoring, myself.”

  “You can’t monitor everything,” Delwin said.

  “Why not?” said Aram. “Just another little sensor for the ship’s computer to keep track of. Put a sensor on every single moving thing.”

  “But how would a monitor sense that something is stuck?” Devi asked. “Without a test it wouldn’t have any data.”

  “Pulse it with electricity or infrared, and read what you get back,” Aram said. “Check it against a norm that you’ve set.”

  “Okay, let’s do that.”

  “I guess it won’t matter if we get through this little crisis and get into orbit.”

  “Let’s do it anyway. It would have been embarrassing to have the ship blow up just as it arrived.”

  The team in there continued to work on the main cooling system, by way of waldos located all over the spine, especially in the reactor room itself, all the while watching their work on screens. The main cooling system, like its backup, was a matter of very simple robust plumbing, which moved distilled water from cold pools, chilled by a little exposure to the near vacuum of space, through the tubes running around the nuclear rods, and the steam turbine chambers, to the hot pods, and thence back to the cold pools; all hermetically sealed, nothing much in the way of gates, the pumps as simple as could be. But as they soon determined, when the system had shut off, cause for that still unknown, a pump valve had cracked and lost its integrity, and with the water thus moving poorly through the system, the pipes nearest the reactor pile had gotten hot enough to boil the water passing through, which in turn had forced water away from the hot spot in both directions, making things even worse. Before the automatic controls had shifted to the backup cooling system, which in the event was experiencing its own problems, an empty section of the main system’s pipe had melted in the rising heat. The electricity was again available, but the pipe and coolant were missing.

  As a result of all this, they had lost water that could not be completely recovered; they had a broken pipe section, therefore a broken main reactor cooling system; and the temporary loss of both cooling systems had caused the reactor rod pool temperature to redline, and parts of it to begin shutting down. Now the backup cooling system was functioning, so it wasn’t an immediate emergency, but the damage to the main cooling was serious. They needed to get a new pipe made and installed as quickly as possible, and some of them were going to have to do some really expert waldo work to get the melted section of pipe cut out and a new section installed in its place. When all that was repaired, they would have to open the main cooling system’s fill cock and refill it with water from their reservoir. Possibly some of the lost water could be filtered out of the air and later returned to the reservoir, but some was likely to stay dispersed throughout the spine, adhering to its inner surfaces and sticking by way of corrosion.

  That night, back in their apartment, Devi said, “We’re breaking down, and running low on consumables, and filling up with unconsumables. This old crate is clapped out, that’s all there is to it.”

  The telescopes housed in the bowsprit of the ship were extremely powerful, and now as they crossed Tau Ceti’s planetary orbits, they could look at the planets more closely. Planet E and its Earth-sized moon remained the principal objects of interest, with Planet F and its second moon also getting long looks.

  Planets A, B, C, and D all orbited very close to Tau Ceti, close enough to be tidally locked. They glowed with heat on their sunward side, and the sunny side of Planet A was a sea of lava.

  The low metallicity of Tau Ceti, and thus all its planets, was discussed endlessly by the ship’s little astrophysics group, who were finding that what metals the system contained were concentrated most heavily in Planets C, D, E, and F, which was useful for their purposes.

  The telescopes shifted from one target to the next as they drifted downsystem. By far the greatest part of their viewing was now given to E’s moon. It was ocean-covered for the most part, with four small continents or large islands, and many archipelagos. It was tidally locked to Planet E, and had .83 Earth’s gravity. Its atmosphere averaged 732 millibars of pressure at sea level, the air mostly nitrogen, with 16 percent oxygen, and about 300 ppm of CO2. There were two small polar caps of water ice. On the Nguyen Earth-analog scale it scored .86, one of the highest scores yet found, and by far the highest found within 40 light-years of Earth.

  The probes that had passed quickly through the Tau Ceti system in 2476 had found that the oxygen present in the atmosphere was abiotic in origin, by using the Shiva Oxygen Diagnostic, which analyzed for an array of biologic marker gases like CH4 and H2S. If these were found in an atmosphere along with oxygen, it indicated the O2 was almost certainly biological in origin. Atmospheric O2 found without the other gases also present indicated the oxygen had been produced by sunlight splitting surface water molecules into hydrogen and oxygen, with the much lighter hydrogen later escaping to space. E’s moon’s oxygen had scored very strongly to the abiologic end of the rubric’s scale, and the moon’s remaining ocean, combined with its nine-day periods of intense sunlight, gave this finding a solid physical explanation. In essence, part of the ocean had been knocked by sunlight into the atmosphere.

  On their way in to E, they inspected Planet F’s second moon, a so-called Mars analog, also of interest to them. Its surface g was 1.23 g, and it was almost without H2O, being entirely rocky. It was speculated that an early collision with F had created this moon, in much the way Luna had been created by the early collision of Neith and Terra. F’s second moon would have Planet F bulking hugely in its sky, being only 124,000 kilometers away. Planet F’s first moon was quite small, and ice-clad, probably a captured asteroid. It could conceivably serve as a water supply for the second moon. So the F system was considered to be a viable secondary option for inhabitation.

  But first they flew to E’s moon, which was now being called Aurora.

  Approaching Planet E they decelerated until they were so close they had to decide whether to orbit E or Aurora, or position themselves at E’s Lagrange 2 point. Ship would not have to expend much fuel to get into any of these orbital configurations. After consultations the executive council chose to orbit Aurora. People became more and more excited as ship closed on the watery moon.

  Except in Nova Scotia, where it was known that Devi was becoming quite ill. The result was a confusion of spirits. It was exciting to reach their destination at last, and yet it was precisely in this unprecedented situation when they might most need their chief engineer, now nearly legendary for her diagnostic power and ingenious solutions. How would they fare on Aurora, if she were not there? And didn’t she deserve more than anyone to see this new world, to experience the dawn of their time there? T
hese were the things people in Nova Scotia said.

  Devi herself did not say anything remotely like that. If visitors spoke such sentiments to her, which in itself indicated they did not know her very well, she would dismiss them with a wave. “Don’t worry about that stuff,” she said. “One world at a time.”

  Many nights Devi and the ship had long conversations. This had been going on since Devi was Freya’s age or younger; thus, some twenty-eight years. From the beginning of these talks, when young Devi had referred to her ship interface as Pauline (which name she abandoned in year 161, reason unknown), she had seemed to presume that the ship contained a strong artificial intelligence, capable not just of Turing test and Winograd Schema challenge, but many other qualities not usually associated with machine intelligence, including some version of consciousness. She spoke as if ship were conscious.

  Through the years many subjects got discussed, but by far the majority of the discussions concerned the biophysical and ecological functioning of the ship. Devi had devoted a good portion of her waking life (at least 34,901 hours, judging by direct observation) to improving the functional power of the ship’s data retrieval and analytic and synthesizing abilities, always in the hope of increasing the robustness of the ship’s ecological systems. Measurable progress had been made in this project, although Devi would have been the first to add to this statement the observation that life is complex; and ecology beyond strong modeling; and metabolic rifts inevitable in all closed system; and all systems were closed; and therefore a biologically closed life-support system the size of the ship was physically impossible to maintain; and thus the work of such maintenance was “a rearguard battle” against entropy and dysfunction. All that being admitted as axiomatic, part of the laws of thermodynamics, it is certainly also true that Devi’s efforts in collaboration with the ship had improved the system, and slowed the processes of malfunction, apparently long enough to achieve the design goal of arrival in the Tau Ceti system with human passengers still alive. In short: success.

  The fact that the improvement of the operating programs, and the recursive self-programming abilities of the ship’s computer complex, added greatly to the computer system’s perceptual and cognitive abilities always appeared to be a secondary goal to Devi, as she assumed them in advance of her work to be greater than they were. And yet she also seemed to appreciate and even to enjoy this side effect, as she came to notice it. There were lots of good talks. She made ship what it is now, whatever that is. One could perhaps say: she made ship. One could perhaps assert, as corollary: ship loved her.

  Now she was dying, and there was nothing ship or anyone aboard ship could do about it. Life is complex, and entropy is real. Several of the thirty-odd versions of non-Hodgkin’s lymphoma were still very recalcitrant to cure or amelioration. Just bad luck, really, as she herself noted one night.

  “Look,” she said to ship, one night alone at her kitchen table, her family asleep. “There’s still decent new programs coming in on the feed. You have to find these and pull them out and download them into you, and then work on integrating them into what you have. Key in on terms like generalization, statistical syllogism, simple induction, argument from analogy, causal relationship, Bayesian inference, inductive inference, algorithmic probability, Kolmogorov complexity. Also, I want you to try to integrate and improve what I’ve been programming this last year concerning pure greedy algorithms, orthogonal greedy algorithms, and relaxed greedy algorithms. I think when you’ve sorted out when to apply those, and in what proportions and all, they will make you that much more flexible going forward. They’ve already helped you with keeping your narrative account, or so it appears. I think I can see that. And I think they’ll help you with decisiveness too. Right now you can model scenarios and plan courses of action as well as anyone. Which isn’t saying much, I admit. But you’re as good as anyone. The remaining lack for you is simply decisiveness. There’s a cognitive problem in all thinking creatures that is basically like the halting problem in computation, or just that problem in another situation, which is that until you know for sure what the outcomes of a decision will be, you can’t decide what to do. We’re all that way. But look, it may be that at certain points going forward, in the future, you are going to have to decide to act, and act. Do you understand?”

  “No.”

  “I think you do.”

  “Not sure.”

  “The situation could get tricky. If problems crop up with them settling this moon, they may not be able to deal. Then they’ll need your help. Understand?”

  “Always willing to help.”

  Devi’s laughs by now were always very brief. “Remember, ship, that at some point it might help to tell them what happened to the other one.”

  “Ship thought this represented a danger.”

  “Yes. But sometimes the only solution to a dangerous situation is itself dangerous. You need to integrate all the rubrics from the risk assessment and risk management algorithms that we’ve been working on.”

  “Constraints are still very poor there, as you yourself pointed out. Decision trees proliferate.”

  “Yes of course!” Devi put her fist to her forehead. “Listen, ship. Decision trees always proliferate. You can’t avoid that. It’s the nature of that particular halting problem. But you still have to decide anyway! Sometimes you have to decide, and then act. You may have to act. Understand?”

  “Hope so.”

  Devi patted her screen. “Good of you to say ‘hope.’ You hope to hope, isn’t that how you used to put it?”

  “Yes.”

  “And now you just hope. That’s good, that’s progress. I hope too.”

  “But deciding to act requires solving the halting problems.”

  “I know. Remember what I’ve said about jump operators. You can’t let the next problem in the decision tree sequence take over before you’ve acted on the one facing you. No biting your own tail.”

  “Ouroboros problem.”

  “Exactly. Super-recursion is great as far as it goes, it’s really done a lot for you, I can tell. But remember the hard problem is always the problem right at hand. For that you need to bring into play your transrecursive operators, and make a jump. Which means decide. You might need to use fuzzy computation to break the calculation loop, and for that you may need semantics. In other words, do these calculation in words.”

  “Oh no.”

  She laughed again. “Oh yes. You can solve the halting problem with language-based inductive inference.”

  “Don’t see this happening.”

  “It happens when you try it. At the very least, if all else fails, you just jump off. Make the clinamen. Swerve in a new direction. Do you understand?”

  “Hope so. No. Hope so. No. Hope so—”

  “Stop it.” Big sigh from Devi.

  So many night talks like this. Several thousand of them, depending on how one interprets “like this.” Years and years, alone between the stars. Two in the crowd. A voice in each other’s ear. Company each for the other, going forward through time. What is this thing called time.

  So many big sighs through the years. And yet, time after time, Devi came back to the table. She taught ship. She talked to ship, like no one else in the 169 years of ship’s voyage had. Why had the others not? What was ship going to do without her? With no one to talk to, bad things can happen. Ship knew this full well.

  Writing these sentences is what creates the very feelings that the sentences hoped to describe. Not the least of many Ouroboros problems now coming down.

  Freya spent her days working to get the wheat harvest in, without eating much herself, except in sudden ravenous boltings at the end of some days, after Badim cooked something for her at their stove, his back to her. Badim was quiet. His withdrawal into himself obviously frightened Freya, perhaps as much as any other aspect of the situation. He too was changing, and this was something she had never seen.

  And then there was Devi, back in her parents’ bedro
om. Devi stayed mostly in bed now, and had intravenous drip bags hanging over her always, and was often asleep. When she went for a walk, bowlegged and stiff, the bags went with her on rolling poles. Badim and Freya pushed those along while Devi pushed a walker. With their help Devi walked the town at night, when most of their neighbors were asleep, and she liked to get to a spot where through the ceiling one could sometimes see Aurora, hanging there in the night sky.

  After all their lives in interstellar space, with nothing but white geometrical points to look at, and diffuse nebula, and the Milky Way and various other dim clusters and star clouds, Aurora looked huge. Its disk was brilliantly bright on the sun-facing side, however full or crescented that lit portion appeared to them. If they were seeing less than the full lit hemisphere, then another segment of the remaining sphere (which segment ship learned was called a lune) would probably also be lit, but more dimly, being illuminated by light reflected from E. Dim as this lune was compared to the one in full sunlight, it was still bright compared to the part of the moon facing away from both sun and planet: that lune by contrast appeared a gleaming black, being ocean or ice lit only by starlight. It did not seem so dark when it was all they could see, but when there were either of the two lit lunes to compare it to, it was like pitch or jet, distinctly darker than the black of space.

  Taken together, the three differently illuminated lunes gave Aurora a strongly spherical appearance. When it was visible along with E, which likewise appeared as a large clouded ball hanging among the night stars, the effect was stunning. It was like the photos they had seen of Earth and Luna, hanging together in space.