Stephen Baxter: Xeelee: Endurance

All the time I was working I clung to my anger at Michael Poole, for it was better than the fear.

So we climbed the flank of the cryovolcano, paralleling the trail followed by the ice spiders, who continued to toil up the slope hauling the last useful fragments of our gondola. We were laden too with our improvised gear – rope cradles, bags of ice-rock chunks for ballast, food packs. Miriam even wore a pack containing the pick of her precious science samples.

It wasn’t a difficult hike. When we had risen above the sand drifts we walked on bare rock-ice, a rough surface that gave good footing under the ridges of our boots. I had imagined we’d slip walking up a slope of ice, but at such temperatures the ice under your feet won’t melt through the pressure of your weight, as on Earth, and it’s that slick of meltwater that eliminates the friction. It was as if we climbed a surface of rough rock.

But despite the easy climb, as we neared the caldera my legs felt heavy. I had no choice but to go on, to walk into ever greater danger, as I’d had no real choice since being press-ganged in the first place.

At last we stood at the lip of the caldera. We looked down over a crudely carved bowl perhaps half a kilometre across, water-ice rock laced with some brownish organic muck. Most of the bowl’s floor was solid – evidently the cryovolcano was all but dormant – but there was a wide crevasse down which the spiders slid into darkness, one after another.

If you listened carefully you could hear a crunching sound, from deep within the crevasse. This crack in the world was what we were going to descend into.

‘Don’t even think about it,’ Miriam murmured to me. ‘Just do it.’

But first we needed a tame spider.

We climbed a few paces down the flank, and stood alongside the toiling line of spiders. Miriam actually tried to lasso one of the creatures as it crawled past us. This was a bit overambitious, as the thick air and low gravity gave her length of cable a life of its own. So she and Poole worked out another way. With a bit of dexterity they managed to snag cable loops around a few of a spider’s limbs, and Poole threw cable back and forth under the beast’s belly and over its back and tied it off, to make a kind of loose net around the spider’s body. The spider didn’t even notice these activities, it seemed, but continued its steady plod.

‘That will do,’ Poole said. ‘All aboard!’ Grasping his own burden of pack and ballast nets he made a slow-motion leap, grabbed the improvised netting, and set himself on the back of the spider. Miriam and I hurried to follow him.

So there we were, the three of us sitting on the back of the beast! ‘On any other day,’ I ventured, ‘this would seem strange.’ That won me a laugh from Miriam.

The first few minutes of the ride weren’t so bad, though the spider’s motion was jolting and ungainly, we had to cling to our cables, and we always had the unpleasant awareness that there was no conscious mind directing this beast to which we were strapped.

Then the lip of the caldera came on us, remarkably quickly. I wrapped my hands and arms tighter in the netting.

‘Here we go!’ Michael Poole cried, and he actually whooped as the spider tipped head first over the lip of the crevasse – and began to climb down a vertical wall. I could not see how it was clinging to the sheer surface – perhaps with suckers, or perhaps its delicate limbs found footholds. But my concern was for myself, for as the spider tipped forward we three fell head over heels, clinging to the net, a slow low-gravity fall that ended with us all hanging upside down.

‘Climb up!’ Poole called. ‘It will be easier if we can settle near the back end.’

It was good advice but easier said than done, for to climb I had to loosen my grip on the cable to which I was clinging. I was the last to reach the arse end of the descending spider, and find a bit of respite in a surface I could lie on.

And all the while the dark of the chasm closed around us, and that dreadful crunching, chewing noise from below grew louder. I looked up to see the opening of this chimney as a ragged gash of crimson-brown, the only natural light; it barely cast a glow on the toiling body of the spider. Impulsively I ordered my suit to turn on its lights, and we were flooded with glare.

Poole asked, ‘Everybody OK?’

‘Winded,’ Miriam said. ‘And I’m glad I took my claustrophobia pills before getting into the gondola. Look below. What’s that?’

We all peered down. It was a slab of ice that appeared to span the crevasse. For an instant I wondered if this was as deep as we would have to go to find our GUTengine. But there was no sign of toiling spiders here, or of the pieces of our gondola, and I feared I knew what was coming next. That sound of crunching grew louder and louder, with a rhythm of its own.

‘Brace yourselves,’ Poole said. Pointless advice.

Our spider hit the ice floor. It turned out to be a thin crust, easily broken – that was the crunching we had heard, as spider after spider smashed through this interface. Beyond the broken crust I caught one glimpse of black, frothy water, before I was dragged down into it, head first. For the ice was the frozen surface of a subterranean ocean.

Immersed, I was no colder, but I could feel a sticky thickness all around me, as if I had been dropped into a vat of syrup. My suit lamps picked out enigmatic flecks and threads that filled the fluid surrounding me. When I looked back, I saw the roof of this vent already freezing over, before it was broken by the plunging form of another spider, following ours.

Michael Poole was laughing. ‘Dunked in molten lava, Titan style. What a ride!’

I moaned, ‘How much longer? How deep will we go?’

‘As deep as we need to. Have patience. But you should cut your lights, Emry. Save your power for heating.’

‘No, wait.’ Miriam was pointing at the ice wall that swept past us. ‘Look there. And there!’

And I made out tubular forms, maybe half a metre long or less, that clung to the walls, or, it seemed, made their purposeful way across it. It was difficult to see any detail, for these visions quickly shot up and out of our field of view.

‘Life?’ Poole asked, boyishly excited once more.

Miriam said, ‘It looks like it, doesn’t it?’ Without warning, she loosened one hand from the net, grabbed at one of the tubes and dragged it away from its hold on the wall. It wriggled in her hand, pale and sightless, a fat worm; its front end, open like a mouth, was torn.

‘Ugh,’ I said. ‘Throw it back!’

But Miriam was cradling the thing. ‘Oh, I’m sorry. I hurt you, didn’t I?’

Poole bent over it. ‘Alive, then.’

‘Oh, yes. And if it’s surviving in this ammonia lava, I wouldn’t mind betting it’s a cousin of whatever’s down below in the sea. More life, Michael!’

‘Look, I think it’s been browsing on the ice. They are clustered pretty thickly over the walls.’

And when I looked, I saw he was right; there the tube-fish were, nibbling away, working their way slowly up the vent.

Poole speculated, ‘Maybe they actively keep the vent open?’ He took a small science box from Miriam’s pack, and there, together – even as we rode that alien’s back down into the throat of the volcano – they briskly analysed the beast’s metabolism, and the contents of the water we were immersed in, and sent the results back to the Hermit Crab. Even Harry’s Virtual head popped up before us, grinning inanely, in that extreme situation.

I had seen enough. With a snap, I made my suit turn its lights off. I had no desire to sit shivering in the dark as invisible ice walls plummeted past me. But I was gambling that curiosity would get the better of Poole and Miriam, and I was right; soon it was Poole whose suit glowed, spending his own precious power to light me up, as they laboured over their pointless science.