Stephen Baxter - Xeelee - Endurance

Michael said, ‘We think you operate it like this.’ He knelt and put his gloved hands to either side of the levers, and mimed pressing them together. ‘We don’t know how heavy the mechanism will be. Hopefully each of us can handle one set of levers, with the help of our suits.’

‘Three mechanisms,’ I said. ‘This is a door meant to be operated by a spider, isn’t it? One handle for each of those three big claws.’

‘We think so,’ Miriam said. ‘The handles look about the right size for that. We think they must need to be worked simultaneously – by one spider, or three humans.’

‘I can’t believe that after a billion years all they have is a clunky mechanical door.’

Poole said, ‘It’s hard to imagine a technology, however advanced, that won’t have manual backups. We’ve seen that the spiders themselves aren’t perfect; they’re not immune to breakdown and damage.’

‘As inflicted by us.’ I gazed reluctantly at the hatch. ‘Must we do this? You’ve found what you wanted – or didn’t want. Why expose us to more risk? Can’t we just go home?’

Miriam and Michael just stared at me, bewildered. Miriam said, ‘You could walk away, without knowing ?’

Poole said, ‘Well, we’re not leaving here until we’ve done this, Emry, so you may as well get it over.’ He crouched down by his handle, and Miriam did the same.

I had no choice but to join them.

Poole counted us down: ‘Three, two, one.’

I closed my gloved hands over the levers and pushed them together. It was awkward to reach down, and the mechanism felt heavy; my muscles worked, and I felt the reaction push me up from the floor. But the levers closed together.

The whole hatch began to vibrate.

I let go and moved back quickly. The others did the same. We stood in a circle, wafted by the currents of the ammonia sea, and watched that hatch slide up out of the ground.

It was like a piston, rising up one metre, two. Its sides were perfectly smooth, perfectly reflective, without a scuff or scratch. It looked brand new; I wondered how old it must be. Michael Poole, fool that he was, reached up a gloved monkey-curious hand to touch it, but Miriam restrained him. ‘I’d like to measure the manufacturing tolerances on that thing,’ he murmured.

Then the great slab, around three metres wide and two tall, slid sideways. Poole had to scurry out of the way. Its scrape across the rough rock ground was audible, faintly. The shifted hatch revealed a hole in the ground, a circle – and at first I thought it was perfectly black. But then I saw elusive golden glimmers, sheets of light like soap bubbles; if I turned my head a little I lost it again.

‘Woah,’ Harry Poole said. ‘There’s some exotic radiation coming out of that hole. You should all back off. The suits have heavy shielding, but a few metres of water won’t hurt.’

I didn’t need telling twice. We moved away towards the GUTengine, taking the light with us. The hole in the ground, still just visible in the glow of our suit lamps, looked a little like one of the ethane lakes on the surface, with that metallic monolith beside it. But every so often I could make out that elusive golden-brown glimmer. I said, ‘It looks like a facet of one of your wormhole interfaces, Poole.’

‘Not a bad observation,’ Poole said. ‘And I have a feeling that’s exactly what we’re looking at. Harry?’

‘Yeah.’ Harry was hesitating. ‘I wish you had a better sensor suite down there. I’m relying on instruments woven into your suits, internal diagnostic tools in the GUTengine, some stray neutrino leakage up here . . . Yes, I think we’re seeing products of stressed spacetime. There are some interesting optical effects too – light lensed by a distorted gravity field.’

‘So it’s a wormhole interface?’ Miriam asked.

‘If it is,’ Poole said, ‘it’s far beyond the clumsy monstrosities we construct. And whatever is on the other side of that barrier, my guess is it’s not on Titan . . .’

‘Watch out,’ Miriam said.

A spider came scuttling past us towards the hole. It paused at the lip, as if puzzled that the hole was open. Then it tipped forward, just as the spider we rode into the volcano had dipped into the caldera, and slid head first through that sheet of darkness. It was as if it had fallen into a pool of oil, which closed over the spider without a ripple.

‘I wouldn’t recommend following,’ Harry said. ‘The radiations in there are deadly, suit or no suit; you couldn’t survive the passage.’

‘Lethe,’ Michael Poole said. He was disappointed!

‘So are we done here, at last?’ I asked.

Poole snapped, ‘I’ll tell you something, Emry, I’m glad you’re here. Every time we come to an obstacle and you just want to give up, it goads me into trying to find a way forward.’

‘There is no way forward,’ I said. ‘It’s lethal. Harry said so.’

‘We can’t go in ourselves,’ Miriam agreed. ‘But how about a probe? Something radiation-hardened, a controlling AI – with luck we could just drop it in there and let it report back.’

‘That would work,’ Poole said. Without hesitation the two of them walked over to the GUTengine, and began prying at its mechanisms.

For redundancy the engine had two control units. Miriam and Poole detached one of these. Containing a sensor suite, processing capabilities and a memory store, it was a white-walled box the size of a suitcase. Within this unit and its twin were stored the identity backups that had been taken of us before our ride into Titan’s atmosphere. The little box was even capable of projecting Virtuals; Harry’s sharp image was being projected right now by the GUTengine hardware, rather than through a pooling of our suits’ systems as before.

This box was small enough to be dropped through the interface; hardened against radiation it should survive a passage through a wormhole – though none of us could say if it would survive what lay on the other side. And it had transmitting and receiving capabilities. Harry believed its signals would make it back through the interface, though probably scrambled by gravitational distortion and other effects; he was confident he could construct filtering algorithms from a few test signals.

The unit was perfectly equipped to serve as a probe through the hatch, save for one thing. What the control box didn’t have was intelligence.

Michael Poole stroked its surface with a gloved hand. ‘We’re sending this beast into an entirely unknown situation. It’s going to have to work autonomously, figure out its environment, perform some kind of sensor sweep, before it can even start to work out how to talk to us. Running a GUTengine is a pretty simple and predictable job; the AI in there isn’t capable of handling an exploration like this.’

‘But,’ I said, ‘it carries in its store backups of four human intellects – mine, dead Bill, and you two geniuses. What a shame we can’t all ride along with it!’

My sarcasm failed to evoke the expected reaction. Poole and Miriam looked at each other, electrified. Miriam shook her head. ‘Jovik, you’re like some idiot savant. You keep on coming up with such good ideas. I think you’re actually far smarter than you admit yourself to be.’

I said honestly, ‘I have no idea what you’re talking about.’

‘The idea you’ve suggested to them,’ Harry said gently, ‘is to revive one of the dormant identity-backup copies in the unit’s store, and use that as the controlling intelligence.’

‘Me and my big mouth.’

As always when they hit on some new idea, Poole and Miriam were like two eager kids. Poole said rapidly, ‘It’s going to be a shock for the copy to wake up, to move straight from atmospheric entry where it was downloaded, to this point. It would be least disconcerting if we projected a full human animus. A complete body.’