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.
It was strange to be so close to them in distance, but so far away in the nonintuitive space of delta vees. Bandwidth between New Caird and Izzy was excellent now, and Dinah had to make a conscious effort not to get distracted by the availability of text messaging and even Spacebook. See you in a few xoxo, Ivy had texted her, and Dinah had sent back something in the same vein, then closed the window.
Vyacheslav was donning one of the blue thermal garments worn beneath space suits. This, she knew, was just a precaution, in case he had to “go outside” on short notice for some reason. Slava had stationed his space suit in New Caird’s airlock, so that he could exit to the outside of the shard if needed, and Dinah had pre-positioned two Grabbs there, to help him get around.
Markus could be pretty unceremonious about things, which was just his leadership style—his way of implicitly telling people he expected them to do their bloody jobs without pep talks beforehand or congratulations afterward. It didn’t work for everyone. Some people liked ceremony. But he hadn’t invited any of those along on this expedition. So there was no particular moment when it all started. They just kept getting closer to the Earth. Slava darted up the companionway to the top of the command module, and a minute later announced that he was positioned before the controls of New Caird. Jiro called out milestones in the startup of the reactor, occasionally proffering hints as to how the figures should be understood: “That is a little faster than I expected . . . settling down now . . . this is according to plan . . . ready to proceed on your command . . .” and so on. Markus’s participation consisted largely of chewing his thumbnail while staring fixedly at his screen. From time to time he would reach out and type something, or swipe and tap on his tablet. Dinah’s work was almost entirely abstract, several layers removed from what obviously mattered. She tried to focus on it and to ignore the sounds of a thousand loose objects settling to the “floor” of Ymir as gravity “came on” due to a combination of Ymir’s increasing thrust and the steady buildup of atmospheric pushback.
“Now,” Markus said.