That someone paused for a few moments at the entrance to the hamster tube that led to it, and detected the haunting tonalities of the Muslim call to prayer. Too bad. He’d thought that the Pod might actually be a good backdrop for the message he was meant to deliver. But he would have to find another place. Directly across, a hatch led into the rambling group of modules that served as Izzy’s sick bay. This had consumed much of the space formerly used by the port-side solar panels. At its farthest extremity, blocked off by an insulated hatch, was the surplus module that had been used as Izzy’s morgue and graveyard since the first Scout launch on A+0.29, when two of the cosmonauts had been found dead on arrival. The terrific mortality rate of those first few weeks had half filled this thing with freeze-dried bodies. Since then, fourteen more had died of various causes: one of a subarachnoid hemorrhage that could just as well have happened on the ground, one of a heart attack, two of suicide, two of equipment failure, four just a few days ago in the sudden depressurization of an arklet struck by a bolide. Those, plus the dead stowaway, were all stored in the morgue. The whereabouts of the other four fatalities could only be guessed at. One was a spacewalker who had simply disappeared. The remaining three had been sleeping in a Shenzhou spacecraft docked to the end of a hamster tube, which had been struck by a bolide the size of a coffee table and essentially vaporized. Performing his video surrounded by free-floating, freeze-dried corpses would shut up the “truthers” but otherwise had nothing to recommend it.

On the opposite “wing,” where the starboard solar panels had once operated, was a roughly symmetrical arrangement of modules used by the General Population for miscellaneous living and working purposes. These connected to the Stack mostly by way of the old American modules: Unity, Destiny, and Harmony. Consequently, there tended to be a lot of humans flying around in those modules, getting from one part of the space station to another or clustering for the equivalent of watercooler chats.

Beyond Harmony was Node X. NASA liked to give these things names by organizing contests for schoolchildren, which was how Harmony had ended up being called that, but the Node X naming project had been defunded before achieving a result, so Node X it was. It had never really found a purpose, so it had become the place where the life sciences gear was stored—or rather the central connector to which the life sciences modules had docked, one by one, as they had been sent up. This part of the Stack was very close to Amalthea, and accordingly well protected, and so it was a good place to store that irreplaceable equipment during the wait for it to become useful. Doob poked his head into several of those modules, hoping to encounter Moira, then remembered that, London girl that she was, she was on third shift, not due to wake up for another three hours—it was about dot 5, predawn in London.

Beyond Node X was the considerably larger SCRUM, which was literally bolted onto Amalthea at its forward end. So it was the forward-most thing in the Stack. Before Zero it had been nearly deserted. Since then it had grown and developed into the space-based headquarters of Arjuna Expeditions. People called it the Mining Colony. They had plugged in more modules until all of its ports were occupied, and then they had begun to attach scaffolding and additional modules—rigid and inflatable—directly to the aft surface of Amalthea.

It was around now that Doob forgot entirely about the task that the flack in Houston had assigned him, and decided to hang out here for a little while and see what was going on. By all rights this ought to have been his favorite part of the Cloud Ark. Yet he never visited, because coming here put him in mind of politics, which stressed him out and distracted him. His earlier conversation with Luisa had brought home to him, however, that ignoring politics might not be the wisest long-term strategy. He might not care about politics, but politics cared about him. And besides, the people who actually worked here—people like Dinah—were terrific. He had no problem with them personally. He should spend more time with them. Right now he was three hours short of the end of his waking cycle. This was the rough equivalent of mid-evening. Time to kick back and grab a beer. No better people to do that with than miners.

The Mining Colony was political for two reasons. First of all and most obviously, it had originated from a public-private partnership of which the private half was Arjuna Expeditions—Sean Probst’s company. Which had been all well and good until he had burst into H2, raised hackles, and ruffled feathers all over the place. Secondly, but much more murkily, there seemed to exist some kind of fundamental disagreement about what the Cloud Ark was supposed to be and how it was expected to develop in the years following the White Sky. Was it going to stay in place, i.e., remain in the same basic orbit? Transition to some other orbit? Would it stay together as a compact swarm or spread out? Or would it split up into two or more distinct swarms that would try different things? Arguments could be made for all of the above scenarios and many more, depending on what actually happened in the Hard Rain.

Since the Earth had never before been bombarded by a vast barrage of lunar fragments, there was no way to predict what it was going to be like. Statistical models had been occupying much of Doob’s time because they had a big influence on which scenarios might be most worth preparing for. To take a simplistic example, if the moon could be relied on to disassemble itself into pea-sized rocks, then the best strategy was to remain in place and not worry too much about maneuvering. It was hard to detect a pea-sized bolide until it was pretty close, by which time it was probably too late to take evasive action. A strike from a rock that size would perforate an arklet or a module of Izzy, but not destroy it; people might get hurt and stuff might get broken, but the worst case was that a whole module or arklet would be destroyed with the loss of a few lives. On the other hand, in the more likely scenario where the Hard Rain included rocks the size of cars, houses, and mountains, detection from a distance would be easier. Evasive action would be not only feasible, but obligatory.

Or at least it was obligatory for Izzy. For a single arklet, it didn’t matter whether it got struck by a rock the size of a baseball or one the size of a stadium. It was equally dead in either case. Izzy, on the other hand, could survive the first of these with the loss of a few modules, but the second would obliterate the whole space station and probably lead to the slow death of the entire Cloud Ark. Izzy had to be capable of maneuvering out of a large bolide’s path.

“Maneuvering” conjured images, in nontechnical minds, of football players weaving among their opponents in an open field. What the Arkitects had in mind was considerably more sedate. Izzy would never be agile. Even if she were, maneuvering in that sense would waste a lot of fuel. If an incoming rock big enough to destroy her were detected long enough in advance, she could get out of its path with a thruster burn so deft that most of her population would not even know it had happened. So, the optimistic view of how this was going to work was that Izzy would remain in something close to her current orbit, with occasional taps on the thrusters that would move her out of the way of any dangerous bolides hours or days in advance of the projected collision. The analogy was made to an ocean liner gliding through a field of icebergs, avoiding them with course changes so subtle that the passengers in the dining room wouldn’t even see the wine shifting in their crystal stemware.

There was, inevitably, a more pessimistic vision in which Izzy was more like an ox blundering across an eight-lane highway in heavy traffic. Depending on who was making the analogy, the ox might or might not be blindfolded and/or crippled.