Poseidon's Wake - Страница 122

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Eunice argued that they should set down at exactly that threshold, thirty kilometres, while praying that each and every variable happened to line up in their favour. If the hull survived the re-entry forces, and the engine did not quite overheat…

Vasin was having none of that. She would consent to a touchdown at fifty kilometres, halfway to the wheel’s summit on the ascendant side. But she would not let Mposi stay where it landed. They would unload the rescue party, allow them to get to a safe distance, and then Mposi would take off again before the wheel’s rotation carried it over the wheel’s summit and then began to lower it too deeply into the atmosphere on the wheel’s downturn.

‘Forty kilometres, if you’re going to make life difficult,’ Eunice said. ‘Then you can stay on station until at least the apex without going too deep into the atmosphere. I like that a lot better than watching you fly off again while we’re still on the wheel.’

‘What you like and what you get are two different things.’

‘Not in my experience. This is space travel, Captain Vasin. There is no part of it that’s risk-free.’

‘Managed risk, then.’

‘What do you think I’m doing if not managing your risk? At forty, the ship won’t know the difference from a fifty. We’re looking at a tiny increase in pressure — not enough to hurt us.’

‘If I give you forty, you’ll push for thirty.’

‘Not this time — I want to live as much as you do. I’d just rather do so knowing we’d done our best for those people.’

‘And the elephant.’

‘The elephant is one of the people. Speaking of which, we’re going to have to find room for him inside this ship. If emergency adaptations are required, now would be the time to start making them.’

The sparring went on like that for the better part of an hour, neither of them conceding any significant ground. Goma would have found it infuriating, but the truth was they still had time to make the final decision. Until Mposi was closer to the wheel, their exact point of landing was up for debate. It would only take a few minutes to go shallower or higher, depending on who won.

Whichever they decided, it was not going to be a simple rescue operation.

In her conversation with Kanu, she had learned that the three survivors of the Icebreaker expedition who had managed to scramble into the groove were wearing spacesuits. But the humans’ suits would not be able to keep them alive until they were in true vacuum. At best, they had the means to hold out until they were twenty kilometres above the surface, and that would be at the extreme edge of survivability. Mposi’s rescue party had to reach them quickly if they were to make any difference to their chances.

Eunice had inventoried the supplies. They had plenty of supplementary oxygen and power cells, and the coupling interfaces ought to be common between the various suit designs. But their longest tether was fifty kilometres, and there was no reliable way of coupling the shorter tethers together to make something longer. No matter which way she looked at it, they would have to make do with that one long tether.

‘Can we get that down to them?’ Goma asked.

‘Yes, I think so,’ Eunice said. ‘Reel out at the maximum speed the winch allows, abseil down the wheel. The wheel’s rotation will tend to act against us, but provided we can move at more than one or two kilometres per hour, we’ll easily beat the rotation.’

‘Faster than that, I hope,’ Goma said. ‘And coming back up?’

‘Haul in the way we hauled out. And if that fails, we just ride the wheel up to the top.’

‘You make it sound easy.’

‘I’m involved, so there’s a very good chance it won’t be. Incidentally, what was the part about “we”?’

‘It’ll take more than one of us to carry the supplies. Besides, there’s a Tantor down there. Ru and I want to be part of this.’

‘Want — or feel you must?’

‘Don’t make this harder than it has to be, Eunice. We’re going down, with or without you.’

‘And the number of hours you’ve spent in a spacesuit…?’

‘We’ll have you along to show us how it’s done, won’t we?’

‘I’d argue with you, but I suspect it would feel a bit like arguing with myself.’

‘Futile?’

‘Boring.’

Mposi continued its approach to the wheel, moving at much less than orbital speed and slowing all the while. Eunice and Vasin continued their horse-trading over altitude and risk. Gradually Eunice appeared to be getting her message through: given the supplies they had, going deep was the only way of reaching Kanu’s party in time.

They circled the top of the wheel, recording its grooved structures at maximum resolution in every waveband Mposi was capable of registering. In the hours since Kanu reached the wheel, the sun had set on that part of Poseidon. It was now night-time at the wheel’s base and would remain so for another ten hours. But the wheel’s top was still catching the refracted light of the setting sun, shining a reddening gold. And there were other wheels, and they would all need to be compared, cross-referenced. There was work here for a lifetime — many lifetimes. They had been allowed access to Poseidon for now, permitted to slip through the cordon of moons on this one occasion, but there was no telling how long that licence might be good for.

Goma figured they had better make the most of it while they had the chance.

She spoke to Kanu again. ‘How are you holding out?’

‘We’re on suit air for fifty per cent of the time. Trying to buy some hours, not that one or two will make much difference. Are you any closer with that rescue plan?’

‘Yes, but it’s going to involve you sitting tight a little longer than you might like.’

She heard the smile in his voice. ‘I’m hardly in a position to complain. What do you have in mind?’

‘We’re going to lower a line down to you. But not vertically — it would be too risky to hover Mposi like that, and we wouldn’t be able to offer you any assistance at your end. Better if we lower the ship down the curve of the wheel. We’ll land at the lowest altitude the captain’s happy with — Eunice has talked her down to forty kilometres.’

‘Is that safe for you?’

‘The ship’s not really built for it. But of course Eunice says safety margins are meant to be tested.’

‘Please, Goma — don’t take any risks on our behalf.’

‘You don’t get a say, Kanu. Besides, you have one of the Risen with you.’

‘That’s true.’

‘Around here, at least, the Risen just became an endangered species again. We owe it to ourselves to do all we can for Hector, but I can’t promise it’ll be easy. Our tether’s shorter than we’d like. If we touch down at forty kilometres, we can just reach you, but you’ll need to hold out until you’re close to the limits of survivability. If all goes well, we should be able to get down to you before you’re much higher than fifteen or twenty kilometres up.’

‘That’ll be cutting it fine.’

‘No other way, Kanu. But we’ll have oxygen and power when we reach you. Don’t be alarmed if you see the ship lift off — Gandhari’s going to circle around for a few hours before coming back in.’

‘This is more than we were hoping for, Goma.’

‘It’s what Mposi would have done. While we carry his name, we’d better try to live up to it.’

‘You already have.’

‘I’m signing off now. Once we’re on the tether, we’ll speak again. For now, keep warm and conserve your supplies. See you soon, Uncle Kanu.’

‘See you soon, niece of mine.’

They lowered into the atmosphere on a spike of Chibesa thrust, dialled back to the minimum necessary to support Mposi against Poseidon’s gravity. It was silent to begin with, the descent as smooth and uncomplicated as when they landed on Orison. But the air was thickening with each kilometre closer to the sea, and as the Chibesa exhaust began to interact with the atmosphere, so the physics of the plasma exhaust began to turn messy. The engine could adjust, up to a point. It damped shock waves and smothered runaway instabilities before they had a chance to manifest as bumps or lurches felt by the human crew. It whispered sweet nothings at turbulence and laminar-flow boundaries. It brought to bear a monstrous amount of computation, calculating its way around the curdled, fractal corners of emergent chaos.

But they had to go deeper.

Vasin was at the controls, her seat pushed out into the armoured eye of the bubble cockpit, shaking her head all the while as if — despite having agreed to this — she was still not convinced that it was anything but the utmost foolishness, guaranteed to wreck them all. Mposi sounded a mounting chorus of status warnings and master caution alarms, and the engine surged and ebbed as it tried to balance the demands being placed upon it.

Deeper still.

Chaotic interaction with the high atmosphere was only part of the problem. Now the heat transfer from the exhaust to the surrounding air was beginning to overload the engine’s own cooling capabilities. Refrigeration pumps and heat exchangers surged and screamed beyond their normal tolerances.

Still more alarms.

But Vasin had given Eunice her word, and Kanu in turn had been led to believe there was a chance of rescue. Goma understood, in a flash of admiration and empathy, that Vasin would not now turn back; her commitment was total. Having said she would do this one thing, their captain would not surrender.

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