Seveneves. Neal Stephenson

pushed off against the top rung of the ladder and flew “down” until she could arrest her momentum against the boiler room grate, then spun herself about so that her feet were touching it and her head was pointed back “up” toward the front door. This brought her eyes level with several flat-panel screens that had been mounted to the walls. They served as status indicators and control panels for the equipment mounted to the outside of the dome. The little nuke was the only thing that mattered to them at the moment. It had a screen all to itself. Dinah woke it up with a tap. It refreshed itself with a graphical display, showing the temperature of the plutonium pellet at its core, its current output level, the RPMs and health metrics of the Stirling engine that converted its heat into electrical power, and the charge level of the batteries and of the supercapacitor that served as a buffer to store energy when it wasn’t needed and release it when it was. Everything seemed normal there. Not much could really go wrong with these things. This one was brand new.

      She pivoted to another display that gave her information about the array of thrusters mounted to the halo just outside. Arklets were pretty short on windows; the only place you could see out was at the forward end, where a couple of small portholes had been let into the dome adjacent to the docking hardware. Just below one of them was what the engineers called a couch and what the casual observer would be more likely to describe as an expensive lawn chair that had somehow found its way into space. Ivy had already strapped herself into it and was waking up another bank of flat-panel screens there. Dinah could hear her murmuring into the microphone on her headset, which she had jacked into the assortment of plastic boxes that, in this context, passed for a control panel. She was running through a checklist with mission control and talking to Markus, who by now must be strapped in at the controls of Arklet 3.

      Gazing around, Dinah saw the gleam of a camera lens, no larger than a raven’s eye, set into a tiny plastic pod on the wall in the middle of the arklet.

      Then, for no particular reason, she started crying.

      There’d been surprisingly little of this. Certain Morse code messages from Rufus were guaranteed to turn on the old waterworks. Ivy and Dinah permitted themselves to shed tears in each other’s presence when no one else was around, and a few other people such as Luisa had joined that club more recently. But there was always something to do, some emergency to take care of, always people around watching. No privacy. This empty arklet was the largest volume of uninterrupted, unoccupied space that Dinah had been inside of since boarding the Soyuz capsule at Baikonur a year and a half ago. It seemed vast to her, and she felt alone in it, and she couldn’t help herself. She knew that the camera was watching her and that she was being recorded on digital video that was being archived. Psychologists in Houston might be judging her fitness for duty at this very moment. But she didn’t care. She’d stopped caring about what the people in Houston thought a long time ago. Once she started crying, it developed a kind of unstoppable momentum and she just had to let it run for a while. Her thoughts had begun to ramble away from her own family and situation and toward the Arkers who would live and die in tin cans like this one. If it didn’t work—if the whole Cloud Ark idea was just a panacea, as some people suggested—then the last thoughts and impressions ever recorded by a human soul might take place in an environment exactly like this one. And maybe Dinah would be that soul.

      The problem with crying in zero gee was that tears didn’t run down your cheeks. They built up in jiggling sacs around your eyes, and you had to shake them off or dab them away. Dinah didn’t have anything to dab with—the plastic coveralls they wore were notoriously nonabsorbent—and so she just drifted in the bottom of the arklet, looking at the light from the control screens through bags of warm salt water.

      “Some assistant you are!” Ivy called back, after letting her go on for a few minutes.

      “Sorry,” Dinah blurted out. “That was mission critical.”

      “Try not to short out any of the equipment. Tears conduct electricity.”

      “I think they made it all pee-proof. Remember, these things are designed for amateurs.”

      “Tell me about it,” Ivy snorted. “The user interface is so easy to use, I can’t do anything.”

      Something light whacked into Dinah’s head. Through the tears she vaguely saw a white object caroming off the nuclear reactor’s user-friendly control panel. Pawing it out of the air, her hands recognized it as a packet of tissues. A high-value black market item. She tore it open, pulled out a few sheets, and began the somewhat delicate process of soaking up the tear-globs without smashing them into sprays of equipment-shorting droplets.

      “I mean, my God, what would Markus think of you?” Ivy demanded.

      It took Dinah a few moments to catch up. “Him and me? You think?”

      “It is so obvious.”

      After a thrilling first few weeks, things had kind of trailed off with Rhys. It was okay. Easy come, easy go. She had never seen him as a stable long-term prospect. The times they’d been living in, and the place they’d been living, weren’t really conducive to long-term pair bonding. Luisa, wearing her anthropologist hat, had watched the spontaneous, mostly short-lived couplings of Izzy’s inhabitants with a combination of dry amusement, scientific fascination, and frank, hilarious envy.

      “I don’t know,” Dinah said, “I see where you’re going, but he seems a little Captain Kirk.”

      “You need a little Captain Kirk in your …”

      “In my what?”

      “In your life. Rhys is too introspective.”

      “Is that a euphemism of some kind?”

      “He’s depressed.”

      “Gosh, I wonder why.”

      “No, not that way. Not about the world ending and everyone dying. I mean that when he’s working on a project he’s full of energy but when it’s finished he just kind of collapses.”

      On the tip of Dinah’s tongue was a remark about how well that observation aligned with Rhys’s lovemaking style, but she held back. “You realize that all of this is being recorded?”

      “Get used to it,” Ivy said, and Dinah could sense her shrug from twelve meters away. “Hang on, gonna give the forward thrusters a little pop—backing out of our parking space.”

      She wasn’t kidding. The thrusters gave off something very like a bang when they went off. Dinah, who actually wasn’t hanging on, felt a few moments of disorientation as the whole arklet moved backward around her while she remained motionless. The green grid dropped away from her and the front door approached—but all so slowly that she needed only to reach out and glide a hand along the ladder to control her relative motion. In a few seconds the forward end of the arklet reached her and she stopped herself against one of the struts of Ivy’s couch. Next to it was a knot of straps and pads, like a rock-climbing harness, which Dinah now spent a couple of minutes untangling and climbing into. The bangs of the thrusters, the hisses and clicks of the associated plumbing, and Ivy’s murmuring into the microphone served as accompaniment while she got herself strapped in and donned a headset of her own. That enabled her to hear the clipped military-style transmissions among Dinah, Markus, and their controller on Izzy. An engineer in Houston weighed in every few minutes with questions and observations.

      Once they had drifted well clear of Izzy, they initiated a programmed burn a few seconds long that took them to a slightly higher orbit. For a while they could see nothing but empty space through the windows. The sun must have risen over the Earth’s limb, because bright round spots appeared on the wall.

      Ivy said, “I have Three on radar and am engaging MAP.” That being the three-letter acronym for Monitored Autonomous Piloting. The operation they were about to perform—the High Five—was deemed way too ticklish to be handled by noob spaceship pilots. It had to be a robotic operation the whole way. But the algorithms, and the sensors that told them what was happening, were all brand new, so experienced pilots had to sit at the controls,