Ramiro hadn’t thought about the technical aspects of the system for years, and as he reacquainted himself he was surprised by its apparent fragility. ‘Disrupt the light for a flicker, and the flow of information is cut. There’s no need to damage anything.’ Although the messages were constantly being converted into a less transient form to be boosted and re-sent, that version of the data only endured forwards in time – it couldn’t bridge a gap into the past. He’d often pictured the messages as a storehouse of documents, a kind of future-archeological find, but they were much more vulnerable than anything written on paper, or even in the energy states of a memory chip.
‘Could we launch some small objects into the external light paths?’ Tarquinia wondered. ‘If each one starts on the mountain close to one of the channel’s outlets, it could probably occult the target star without being picked up by a surveillance camera first.’
Azelio said, ‘The outlets will have to be on the base of the mountain, won’t they?’
‘Yes,’ Tarquinia replied. ‘Unless they’ve turned everything around while we were gone.’
‘We’d need to know exactly which orthogonal stars they’re using,’ Agata pointed out.
‘Maybe our collaborators will have that information already,’ Ramiro suggested. ‘So if we can offer them some miniature automated craft to fly up from the mountain and block those stars, why wouldn’t they use them?’
Azelio said, ‘So who’s going to build these things without being noticed? They’ll need accelerometers and photonics in order to navigate with any precision. If we make them ourselves on the Surveyor, we won’t stand a chance of smuggling them out when we dock. But on the Peerless, all the workshops and stores will be under surveillance.’
‘We could release them before we dock,’ Agata suggested. ‘Send them out to hide somewhere. If they’re small enough, and we time the whole thing carefully, they could pass from the Surveyor to the slopes undetected.’
‘And then what?’ Azelio pressed her. ‘They adhere to the slopes somehow, and then crawl towards the base – like insects crawling along a ceiling?’
‘Yes.’ Agata wasn’t backing down, but the proposal was growing more ambitious by the moment.
‘And then later,’ Azelio said, ‘since we won’t know the coordinates in advance, we have to be able to instruct them, remotely, to crawl to a particular take-off point and then fly along a certain trajectory. Without the signal being detected.’
Tarquinia disagreed with his last claim. ‘If a brief encrypted signal is picked up by the authorities, what can they do about it? So long as they can’t pin down the exact source or destination, mere detection need not be a problem. Even if they take it as a sign that some form of attempted sabotage is under way . . . they would have had that possibility in mind for the last three years, regardless.’
Azelio hesitated. ‘So why would they even try to stop us? They know the disruption is going to happen – so unless all this clandestine activity is irrelevant and a meteor is going to be responsible, this is a battle they know they can’t win.’
‘They’re not going to give up, any more than we are,’ Agata replied. ‘Do you see any sign in what we’ve heard from the mountain that the Council have resigned themselves to a state of fatalistic powerlessness?’
‘No,’ Azelio conceded.
‘Think of it as a kind of equilibrium,’ Tarquinia suggested. ‘I’m sure there are limits to how far the Council would go to try to stop the inevitable, but there must be limits, too, on how supine they’ll become: they’re not going to shut down the system themselves, or release all the anti-messagers and let them go on a rampage with mallets. They’ve taken a stance and they’re going to pursue it as far as they can. When this is over they’ll be looking for a political advantage in the details of the fight, as much as in the outcome.’
Azelio was looking disoriented. ‘I want this to work,’ he said haltingly. ‘But every time I stop and think about it, it feels as if all we’re doing is playing some kind of game. Shouldn’t we be trying to build better meteor detectors? If we really are the only people left with any hope of innovating, why not design a device that could actually save the mountain – instead of one for faking its death?’
Agata said, ‘If we saved the mountain from a meteor, don’t you think we’d know about it?’
‘I have no idea.’ Azelio rose from his seat. ‘But what we’re doing now is pointless.’ He walked out of the cabin.
In the silence, Ramiro felt his own confidence faltering. ‘I don’t know how to reason about this any more,’ he said. ‘If it’s a meteor that could actually kill us, isn’t that where our efforts should go? Forget what the messages say or don’t say about it: if we do our best to build something useful, how can that fail to make a difference?’
Agata inclined her head, expressing some sympathy with the impulse. But she wasn’t swayed. ‘I was the one who tried to argue that there’s no such thing as an undetectable meteor – but what do we have on board for tackling that problem? A single time-reversed camera, and no facilities for building new photonic chips or any kind of high-precision optics. Even if we came up with a glorious new design, how are we supposed to manufacture a whole network of surveillance cameras and get them deployed? They can’t just be drifting around the mountain detecting hazards for their own amusement – if they find something, they have to be able to trigger either a coherer powerful enough to deflect the thing, or start up the engines and make the whole mountain swerve. Do you really think we’d be able to do that in secret?’
‘Maybe the Council will finally exercise enough discipline to keep it all quiet,’ Ramiro replied.
‘If they’re capable of that,’ Agata countered, ‘then they’re capable of doing a vastly better job than we are with the entire project.’
Ramiro gave up. He desperately wanted everything to work in the old way, when he could wrap his mind around a self-contained problem and take it apart without having to think about the entire history and politics of the mountain. But wishing for those days wasn’t going to bring them back. ‘Then we should go ahead with the star-occulters for our hypothetical saboteurs,’ he said. ‘Find a way to build them, and a way to keep them secret, and then hope that the cosmos takes us up on the offer to explain away the disruption with one simple, harmless conspiracy.’
26
Agata took hold of one end of the slab of calmstone, Ramiro the other, then they lifted it onto their shoulders and stood facing each other, some four strides apart.
‘Are you ready?’ Tarquinia asked.
‘I’m not sure how steady this will be,’ Agata replied.
‘That doesn’t matter. I just want you to be able to keep your grip when there’s a force applied from below.’
Agata put a second hand on the slab. ‘All right. Go ahead.’ The improvised test rig looked alarmingly amateurish, but the ceiling of the cabin was made of the wrong material, and in any case they didn’t want to leave it covered with incriminating marks. They’d hunted through the storeroom for something to serve as a trestle, but there’d been nothing ready-made, so in the end their bodies had seemed like the most expeditious substitute.
Tarquinia pushed a button on the remote control and the occulter rose from the floor. The core of the tiny craft was a dodecahedron about a span wide, with air nozzles fixed in the centres of eleven of its pentagonal faces. Attached to the top, twelfth face was a linear assembly, a pair of arms three or four spans long, as densely packed with gears and linkages as anything from the age of clockwork.