The Arrows of Time

Ramiro could not have been less comforted. ‘High-velocity debris in the void – possibly spiced with antimatter. Do you really want to fly through that?’

‘If we give ourselves enough time, the risk will be negligible.’

‘And how much time is ours to give?’

Tarquinia turned to the navigation console, instructing it through the photonic corset that wrapped her torso beneath the cooling bag. When she’d finished, a flight plan appeared on the screen.

‘If Greta’s theory is right,’ Tarquinia said, ‘we’ll be able to match trajectories with the rogue in slightly more than five bells – about half a bell before the impact. If we set the explosive’s timer for three chimes, that will leave another three chimes for the debris to spread out – enough for the bulk of it to miss the Station. And in three chimes, we can put almost three severances between ourselves and the explosion. The rogue will still be accelerating as fast as it can towards the Station, so if we scarper in the opposite direction we’ll get the benefit of both engines.’

Ramiro was slightly mollified. Three severances wasn’t much on the scale of this map, but it was more than six gross times the height of the Peerless. The shrapnel they were fleeing would never slow down, but it would grow ever sparser.

‘So is Greta right or not?’ he asked. They’d lost the link with the Peerless, so they’d had no updates on the rogue’s actual behaviour.

Tarquinia flicked a switch on the console; a moment later the link was restored.

‘What did you do?’ Ramiro demanded.

‘I vented some air through an outlet next to the photoreceptor,’ Tarquinia explained. ‘Sometimes it just gets dusty.’

Greta asked anxiously, ‘Can you hear me?’

‘Loud and clear,’ Tarquinia replied.

‘The rogue came to a halt three lapses ago, and reversed without a pause. It’s headed straight back to the Station.’

‘Understood,’ Tarquinia said cheerfully. She made no move Ramiro could see, but she must have sent a command through her corset because the flight plan on the screen changed from grey to red – transformed from a hypothetical doodle to a set of firm instructions. The sky through the dome rotated a quarter-turn as the gnat swung around to redirect the engines.

‘We’re really going to do this?’ Ramiro asked numbly. He’d been half-hoping that the rogue would set out for the Peerless instead; forewarned, the mountain’s defenders could have launched any number of pilotless gnats against it, so the risk of it actually striking its target would have been vanishingly small. ‘What if we programmed a collision instead?’ he suggested. ‘Then we can climb out here and wait to be rescued.’ That would mean half a day in the void, but they had locator beacons on their cooling bags and they could take a couple of extra air tanks from the gnat.

Greta said, ‘Absolutely not!’

Tarquinia gave the idea some thought. ‘We don’t know the rogue’s trajectory with enough precision to ensure that we’d hit it, but I suppose we could use the explosives to make a near miss almost as good. The only trouble is… it wouldn’t take much of a course change by the rogue to ruin the whole plan. Even if you reprogrammed our navigation system so they could tweak the trajectory from the Peerless, the explosive isn’t that sophisticated: once we set the time delay, it would be impossible to change it remotely.’

Ramiro was prepared to accept this argument, but Greta felt obliged to add her own reasons. ‘The Council still wants the rogue’s navigation system analysed,’ she said. ‘The trajectory might be obvious now, but there could be other information about the perpetrators that can be gleaned by studying what they’ve done.’

‘Yeah, I’m sure they signed their names in the software.’ Ramiro didn’t doubt that there was such a thing as programming style, but the idea of identifying a saboteur on the basis of anything so vague was ludicrous. ‘I’ll be happy if we manage to keep the Station from being hit, but once that’s guaranteed I’m not risking my life humouring the Councillors.’

Greta didn’t reply; she knew better than to push him now.

‘So… we’re going ahead with the interception?’ Tarquinia asked tactfully.

Ramiro stared at the flight plan: the map of their future for the next five bells. As far as he knew, on every other occasion when two gnats had come together in the void they’d had cooperating pilots, and their main engines had been shut off for the approach. But here were the trajectories, meeting up perfectly right before his eyes.

‘Why not?’ he said. ‘What could possibly go wrong?’

At Ramiro’s request, Tarquinia showed him a version of the flight plan with their acceleration marked. Translating between the standard maps and the starry emptiness around her might have been second nature to Tarquinia, but the only way Ramiro could hope to stay oriented was by knowing which direction would feel like ‘up’ to him for the various stages along the route.