“She’s right about the ‘breathless’ part of it,” Dinah muttered to herself, closing the window and looking at the time stamp again. It had been transmitted three hours ago. Then, only half an hour ago, Ivy had responded with a counter-communiqué. Dinah didn’t read it, but based on the subject heading she knew what it would say: don’t listen to J.B.F., stay in formation, we need you and you need us.
But from what Dinah was seeing, both through the optical telescope and on Parambulator, Ivy’s message had come too late to forestall the departure of a large number of arklets. Somewhere out there, up above them in higher orbit, a new swarm was taking shape, running its own, independent instance of Parambulator, and looking to J.B.F. for leadership.
Dinah had been through many emotional ups and downs while retrieving Ymir. More downs than ups, of course, given the fatality rate. In a strange way, however, the emotional high point was just a few moments ago when she had scanned the word “desperate” in J.B.F.’s communiqué. She rather liked being described as desperate, particularly when she was just on the verge of succeeding.
Parambulator was working on her screen now. She used it to check the status of those three Flivvers. They were still closing. Messages were starting to come in from their pilots, trying to make out whether anyone was still alive in the shard, whether it was safe to approach.
Dinah texted back: One survivor. Stand clear for a sec while this thing takes a big glow-in-the-dark crap.
Then she pulled up the window she used to communicate with her network of robots and typed in a single-word command: JETTISON. It was the name of a program that Sean had started, Larz had improved, and Dinah had recently finished. It was a program meant to be run simultaneously by every robot in the shard, as well as some other systems down in the boiler room.
A prompt came back: ARE YOU SURE Y/N
Y, she typed.
CONGRATULATIONS!!! came back. The dead crew of Ymir had sent her a message from the void.
She pushed herself over to the companionway, got her head aimed “down” through the hole in the floor, and pulled herself straight to the bottom level of the command module. The hatch in the floor — the one that led to the ice tunnel that terminated in the boiler room — had already been closed, as a basic safety measure. But Dinah verified that one last time and made sure it was sealed. Because in a few seconds, there would be nothing but vacuum on the other side of it.
Ymir had begun grumbling. Dinah felt as if she were trapped inside the belly of a frost giant with indigestion. What she was hearing, she knew, was the collective noise made by thousands of Nats, and hundreds of larger robots, as they moved to safe positions on the inner surface of the hollow shard and gnawed away at the structural webbing that connected it to the reactor core.
She returned to her seat in the command module and pulled up a video feed from the interior of the shard. Its walls were now thin enough to admit some sunlight, and so it had become a sort of vast pellucid amphitheater where all of those robots could look inward to the smooth beryllium pod — a neutron-reflecting shroud — surrounding the reactor core. Formerly this had been buried in ice; the recent excavations made to fuel the big perigee burns had left it exposed, also revealing the smaller pod of the boiler room mounted on its side, and the system of hoppers and augers that fed it. Aft of that was what remained of the ice cavern of the nozzle bell, now mostly melted away to expose the blackness of space beyond. The only thing now holding the reactor chamber in place was the massive central thrust pillar, a tree trunk of ice that grew from its forward end and extended straight up to the solid nose of the shard, where the command module was embedded.
JETTISON did her the courtesy of showing a countdown on the screen, so that she could plug her ears. When it hit zero, a sickening crack resounded through the whole structure. The video feed showed a brilliant spray of ice blown free from the central pillar, just above where it connected to the reactor vessel. Demolition charges, placed there long ago by Sean’s crew, had detonated and severed the connection. For a moment she feared nothing further would happen, but then jets of white steam lanced from the reactor vessel’s rounded top. JETTISON had opened valves, releasing pressure that had built up in the chamber from the reactor’s residual heat, and those valves were now acting as makeshift rocket engines, pushing the whole reactor, and everything attached to it, down toward the vacancy of the nozzle.
The entire reactor chamber dropped out the bottom of the shard and was gone.
If JETTISON continued to do its work, the reactor, now a free-floating vehicle, all brawn and no brains, would execute a few clumsy maneuvers to kill its own orbital velocity and drop itself into the atmosphere.