Doob looked tired, and nodded off frequently, and hadn’t eaten a square meal since the last perigee, but he pulled himself together when he was needed and fed any new information into a statistical model, prepared long in advance, that would enable them to maximize their chances by ditching Amalthea and doing the big final burn at just the right times. But as he kept warning Ivy and Zeke, the time was coming soon when they would become so embroiled in the particulars of which rock was coming from which direction that it wouldn’t be a statistical exercise anymore. It would be a video game, and its objective would be to build up speed while merging into a stream of large and small rocks that would be overtaking them with the speed of artillery shells.
The details, the sudden distractions and improvisations, piled up and thickened in a way that made Dinah think of a sonic boom on Old Earth: the onrushing stream of air thickening and solidifying in the path of the airplane, turning into a barrier that must be broken through or succumbed to. They seemed to break through it at the point when Michael and two other spacewalkers pulled on their cooling garments, much patched and mended, and donned their space suits. Doob had the incoming heptad on radar, then on optical, and verified that it was on course to rendezvous with them. This meant, of course, that the heptad was on a collision course with Endurance; the difference between a collision and a rendezvous was the final burn of the heptad’s thrusters that would slow it down at the last minute and bring its params into nearly perfect synchronization with the larger ship’s. Endurance herself, still burdened with Amalthea and with many tons of stored propellant, had next to no maneuverability, and so it would all be up to A?da, or whoever was at the controls of her heptad.
The reunion of Endurance and the Swarm began, as it turned out, with a collision. It was not a catastrophic high-speed collision, but it certainly was no orderly and controlled rendezvous. A?da had the presence of mind to give them about thirty seconds’ warning. Until then it had all been going well. The heptad had approached, using its thrusters to kill most of its velocity relative to the larger ship, and executed some little burns intended to bring it home to the docking port. Then A?da announced, in a barely controlled tone of voice, that one of the thruster modules had run out of propellant and could no longer perform its function.
“It’s too heavy,” Zeke muttered. “They loaded in too much cargo; the thrusters are eating too much fuel trying to push all of that crap around.”
The heptad came in too fast and at the wrong angle and crashed into Caboose 2, which was a module, recycled from the wreckage of the Shipyard three years ago, that they had plugged into the back of H1 to serve as the aft-most thing in the Stack. They saw it happen on their screens, they felt it in their bones, and they heard the three spacewalkers exclaiming and cursing. A little storm of debris emerged from a hole that had evidently been torn in the skin of Caboose 2.
“C2 depressurized,” Tekla reported. “Sealed off from Stack.”
The debris cloud included one large object that had two arms, two legs, and a head. The limbs were flailing. Everyone watched silently.
“We lost Michael Park,” one of the other spacewalkers announced.
“We need more people back there,” Ivy announced to the crew in the Hammerhead.
Ivy’s message was clear. Later we will mourn for Michael. Now we have other things to worry about.
“Moira, you stay,” Ivy added.
Moira hadn’t even moved. She was accustomed to being treated, against her own will and instincts, like a cherished and fragile child.
“Maybe you could talk to Michael on the radio. He’ll be alive for a while.”
Moira nodded, swallowed hard, and focused on her laptop, entering the commands needed to establish a private voice link to Michael.
“Dinah, you stay here—run the robots. We are going to have to do some improvising. Bo, go back. Steve too. Luisa, deal with A?da over voice—for me it’s too much stress and distraction. Stay in the Hammerhead and make that problem go away for me. Doob, stay here. Zeke, go back.”
Ivy looked around. “If I haven’t mentioned your name yet, go back and see what you can do. Doob, you’re the weatherman. Your job is to make announcements about the storm and when it’s going to hit.”
“Half an hour,” Doob said. “But yes. I will do that.”
Moira, headphones on, had retreated into the quietest corner of the Hammerhead and was engaging in a murmured conversation with Michael. She was holding a cloth over her eyes to absorb tears before they broke loose in the cabin. Luisa had already gone into her assigned role and had been listening to a voice transmission from A?da. “She says she is going to try again.”
“I thought her thrusters were empty,” Ivy said.
“She can transfer propellant from some of the other thruster modules to the empty one. It’ll take a few minutes. She requests instructions on where to make the next attempt, since the docking port on Caboose 2 has been rendered unusable.”
With a bit of deliberation they agreed that the heptad should make its next attempt on a docking port in the old Zvezda module.