‘We’ll follow the whole flight plan as closely as we can.’ Ramiro reviewed the list, bringing the figures back onto his skin as he checked them. ‘What are those last sets of numbers?’

‘The coordinates of the light collectors.’

Ramiro hadn’t expected to be given the targets themselves until he’d reported back on the first stage of the process. ‘So that’s it? We just fly the occulters there . . . and then what?’

‘The bombs are all controlled by timers,’ Giacomo explained. ‘All you need to do is get them to the right place.’

‘What do we do if something goes wrong? How can we contact you?’ Ramiro was prepared to accept responsibility for the occulters, but if anything else malfunctioned he’d have no idea what the options might be.

‘Nothing goes wrong,’ Giacomo assured him.

‘You can’t know that,’ Ramiro protested. ‘Not after the private messages are squeezed out—’

‘That late?’ Giacomo paused, struggling to frame an answer, as if he’d lost the habit of imagining anything beyond the reach of his foresight. ‘The disruption is ours,’ he said finally. ‘We’ve been planning it for longer than the system’s been in existence. We know that it happens – and we know that we’re trying harder to make it happen than anyone else. So how can we possibly fail?’

Ramiro moved away from the console and let Tarquinia check the alignment of the link against her own calculations. They’d set the beam to be as narrow as they dared, to minimise the chance of anyone detecting it on its way out to the slopes. But if they failed to aim it at the precise location where they’d left the first occulter clinging to the rock they’d be risking discovery for nothing.

‘This looks right to me,’ Tarquinia said.

‘Are you sure?’

‘In the end it’s just arithmetic and geometry,’ she replied. ‘If I do it a dozen more times I’ll still get the same answer.’

Ramiro had already entered the coordinates of the nearest cache into the software. He tapped a key on the console and a tight burst of UV erupted from the link. The confirmation came back immediately: the occulter had received the message and was proceeding to act on it.

‘Perfect!’ Tarquinia declared.

‘So far.’ It would take the occulter three days to crawl across the mountain to its first rendezvous. Ramiro pictured the prototype clanking down the plank towards him, back on the Surveyor. They’d made allowances for the machines losing their footing and needing to recover, but the complex manoeuvres required to pick up the cargo would cut into the air supply, and the extra mass being lugged around would shrink the margin for error even further.

Tarquinia said, ‘Next target.’

Their run of luck continued for a while, but the fifth occulter failed to reply. Ramiro rechecked the direction of the link, then broadened the transmission, but it made no difference.