As well, there was an understanding, widely shared but rarely spoken of, that men were not the scarce resource. Women—to be specific, healthy, functional wombs—were. Acting on that belief, or perhaps just electing a more socially constructive form of suicide, men continued volunteering for hazard duty, instinctively herding the women toward the protected interior spaces of the ship; and when the women objected to it, as some did, they were apt to be shut down by the simple, hard-to-argue-with assertion that their lives and health had to be preserved at all costs.
Communication with the Swarm was sporadic and tended to come in bursts, when the Swarm needed something. The groups had separated under conditions that would have been deemed a state of war had the Break not happened in the midst of a catastrophe more deadly than anything that one side could have inflicted upon the other with force of arms. Neither side was likely to begin trusting the other anytime soon. Free, Internet-style communication between them was forbidden on both sides, since it could have been used for purposes that were mischievous or worse. The channel between Swarm and Endurance was more akin to a hotline linking two Cold War capitals. It went unused for months at a time. This was not so much a matter of the two sides snubbing each other as it was that they were both fully occupied trying to stay alive. Ivy and J.B.F. were like the captains of two damaged ships, many miles apart in stormy seas, with other things on their minds. When the channel was used, it was to negotiate terms of exchanges between the two groups. Neither side was of a mind to share much information about its status. But much could be inferred from the things that the Swarm urgently asked for: mostly propellant, but also the sort of medicine used to treat radiation sickness, blight-resistant strains of food crops, nutrients, spare parts for CO2 scrubbers and for the Stirling engines that supplied power to arklets. In exchange they offered mostly food, which was the only thing they could make that Endurance didn’t already have.
Eleven weeks following the Break, a solar flare had occurred, followed by an event known as a coronal mass ejection: a vast release of charged particles hurled out from the sun into the solar system. With its array of sensors, some of which were always pointed toward the sun for just this reason, Endurance had seen the storm coming and had sent a warning message to the Swarm. In those days Endurance had been well inside the protection of the Earth’s magnetosphere. That plus the shielding provided by iron and ice had enabled her crew to ride out the storm with little exposure to its radiation. They had no way of knowing, though, whether the Swarm had even received or understood the warning. The danger of coronal mass ejections had been well understood by the Arkitects, who had provided “storm shelters” in each arklet: sleeping bags, in effect, made so that water could be pumped into the space between their inner and outer walls, surrounding the occupant with molecules that were good at absorbing high-energy protons. The arklets were also stocked with doses of a drug called amifostine, which protected DNA from damage produced by the free radicals generated in the body by radiation exposure. The scheme was a good one provided the Arkies had at least half an hour’s advance warning and enough water in their arklets’ tanks to fill up all the shelters. They practiced it every so often, as sailors would perform lifeboat drills. But there was a lot that could go wrong, and it seemed unlikely that all eight hundred Arkies had made it through the storm unscathed.
In the ensuing three years there had been ten more coronal mass ejections big enough to worry about. Endurance had transmitted a warning to the Swarm in each of those cases but never received an acknowledgment.
It was worrisome that the Swarm always seemed to want more water. Since the water of an arklet’s ecosystem was recycled, the only way the arklet could lose it was by expending it as propellant: splitting it into hydrogen and oxygen and feeding it to a thruster. All the arklets in a swarm would have to do this from time to time, simply in order to remain in formation. That was true even if they never dodged a rock and never changed their orbit around the Earth. But it seemed that they had changed their orbit on several occasions, making it higher and more circular to keep it clear of the Van Allen belts. Presumably they had their reasons for doing so. But if they ran so low on water that they couldn’t fill their storm shelters when needed, they were open to a disaster that might kill most or all of them at a stroke. Ivy could only assume that they were still reasonable people and that if things got that bad, they would call for help. In the meantime, she tried to guard against the seductive idea that Endurance had all the water it could ever need. There weren’t going to be any more Ymir expeditions. The water they carried with them might be all that the human race had to live on for hundreds of years.
She had already made up her mind what she would say if J.B.F. ever contacted her with an urgent demand for storm shelter water: nothing doing, come to us, rejoin the crew of Endurance and take shelter here. She wondered, sometimes, if J.B.F. had anticipated that Ivy would make such a demand, and just how far she was willing to go to avoid such an unconditional surrender.