Seveneves - Страница 103

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“It’ll affect our operations,” Ivy concluded. “But this is a drill we know pretty well. Take amifostine. Get your space walks finished before it hits. We should make arrangements to accommodate all nonessential personnel in the Hammerhead. Some of us will have to be down farther in the Stack, but we’ll have storm shelters ready.”

“What about. . them?” Michael Park asked.

“They are a problem,” Ivy admitted. “They’re in plastic arklets. They’re gonna get cooked. Even if they have any amifostine left, even if they have enough water to fill their storm shelters, they’re going to take damage. Ethically, we need to bring those eleven aboard Endurance and get them to safer places.”

“The original plan was to send three people out on an EVA to lock down their heptad, make it fast to the stack, so that we could maneuver,” said Zeke Petersen. Of all the crew of Endurance he looked the most similar to his pre-Break appearance. He was skinnier, of course, with a bit of gray around his temples, but his health was still good, and he’d managed to keep his electric shaver working, so he was beardless. After the deaths of Fyodor, from an accident, and Ulrika, from a stroke, Ivy had designated him Endurance’s second in command.

He referred to the fact that Endurance was about to shed 99 percent of her mass, which meant that the same complement of engines, producing the same thrust, could make her accelerate a hundred times faster. The gee forces still would not be extreme — well within the range that humans could tolerate — but the maneuver would impose stresses on the ship’s frame the likes of which it had never experienced before. This was another of those eventualities that they had foreseen long ago and built into Endurance before covering her with ice.

So most of Endurance came prerigged for higher acceleration. Provided that nothing had broken during the last three years, she’d hold together, albeit with a lot of loose junk sliding around her interior spaces the first time they hit the throttle.

They hadn’t planned, though, for the last-minute addition of the heptad from the Swarm. This was awkward. It would be connected to the Stack by a docking port, which wasn’t designed to take a lot of mechanical strain. It was heavy, because Aïda and her crew had crammed it full of supplies and strapped even more to the outside of it. For the same reason, Ivy didn’t want to just ditch it — they could use those supplies. So the plan had been for three spacewalkers to greet the heptad and lash it into place with cables as soon as it arrived.

“We’ll just have to see what we can do with robots,” Ivy said, looking toward Dinah and Bo. “Just about everything we have out there is Grimmed, correct? So it can operate even in heavy radiation.”

“We’ll get ready for that,” Dinah agreed.

“As soon as the heptad docks, the robots get to work,” Ivy said, “locking it down as best we can. We open the hatch and get the eleven down through the hamster tubes as fast as possible — they’ll have no protection whatsoever while they’re moving through those tubes. We’ll have storm shelters waiting for them. They can climb into those and ride out the rest of the journey. The flight crew will operate out of the Hammerhead.”

THE NEXT TWO DAYS REMINDED DINAH OF THE NEW CAIRD EXPEDITION, in that there was a lot to do but no way to affect the schedule. They were at the mercy of astronomical events. Part of her wanted to pull all-nighters until this thing was finished, but she knew she had to be well rested and fed when it counted, and so she forced herself to eat and sleep on the usual schedule. When awake, she worked on preparations for the arrival of the heptad, pre-positioning Grabbs near the docking port that it would use, connecting cables to suitable anchor points, tuning up the programs that the robots would execute when it came time to snap the other ends of those cables onto the heptad, rehearsing them to check for places where the cables might snag.

The timeline gradually came into clearer focus. Aïda sent out a sharp request for amifostine and water to fill their storm shelters. Of course, it was impossible for Endurance to comply. They had plenty of both, but they had long since cannibalized all of their MIV parts and so they had no way to transport them.

Aïda decided to roll the dice by committing all the water she had left to a large burn that would bring them to the rendezvous with Endurance a little earlier than they’d originally planned. Meanwhile Doob’s space weather forecast was becoming more precise; he had a better idea now of when the radiation storm would break over them and thought that the timing was looking favorable. The heptad might arrive before things got bad. It might be okay after all to have some spacewalkers out there to cooperate with Dinah’s robots.

Dinah didn’t know how to feel about that. The schedule had been accelerated, and now she had to take into account the vagaries of human spacewalkers. If Aïda’s heptad docked soon enough, Doob pointed out, they might be able to transfer many of her heavy supplies through the docking port into the Stack and thereby reduce the awkward strains that all of Dinah’s cables were meant to take up.

Meanwhile Ivy and Zeke, the pilots, were addressing similar last-minute convolutions in their mission plan. As they got nearer, they got better information about the part of the debris cloud that they’d be maneuvering through. They could clearly make out Cleft’s radar signature, as well as those of many other big rocks that traveled in its vicinity. A clutter of faint noise and clouds on the optical telescope gave them data about the density of objects too small and numerous to resolve. All of it fed into the plan.

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 Aïda, 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. Aïda 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 Aïda 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.”

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