The Arrows of Time

by Greg Egan

  Azelio seemed to be focused on the Surveyor itself, so Agata followed his lead and tried to think of the disc of the hull as her horizon. Still clinging to the hand rings outside the airlock she turned her body until it was perpendicular to the disc, then she released her grip and drew a short arrow on her chest that pointed towards her head. The jetpack obliged with a gentle push in that direction; when she’d ascended half a stride above the hull she drew a stop-line that killed her velocity. The jetpack was keeping track of all the acceleration it delivered – along with any bumps and pushes she inflicted on herself – and it knew how to return her to her initial state of motion.

  She followed Azelio to the rear of the hull, opposite the main cabin and its window, and halted beside him. The two agronomy pods mounted here were roughly cubical, each about as broad as Agata was tall. Azelio grasped a ring to brace himself, lit the scene with the coherer mounted on his helmet, then began turning the first of the eight wide, hollow bolts that held the first pod in place. Agata had arrived upside down for the task; she secured herself with her foot through a ring, then squatted down so she could grip another with a hand and right herself. She switched on her own coherer and squinted at the disc of brightness she’d imposed on the starlit hull; it was strange to see the sharp details summoned out of the grey shadows, as if the Surveyor of the void had become the Surveyor of the workshop again. Then she reached into the bolt closest to her and took hold of the crossbar within. The crossbar needed a twist around its own axis to disengage the spring-loaded pins that locked it in place, then it served as a handle to turn the bolt.

  ‘My arm’s tired already,’ Azelio confessed. ‘Why couldn’t they make this a job for power tools?’

  ‘If you want to run everything on compressed air, you’d better hope there’s sunstone on Esilio.’ Agata’s own forearm was aching. ‘Let’s face it, we’ve all grown soft. If you asked me to harvest a crop manually, I think it would kill me.’

  ‘Lucky you don’t want to migrate, then.’

  By design, the bolts could not be withdrawn entirely from their threaded holes, but once all eight had been unscrewed as far as possible the locking plates on the pod were freed from their slots in the hull.

  Agata got into position on the opposite side of the pod to Azelio; the symmetry was necessary to extract the thing smoothly, but it meant they were hidden from each other. ‘Move it as gently as you can,’ he instructed her. ‘The last thing we want to do is give it more momentum than we can control.’ With their feet re-formed into hands to grip the rings on the hull, they slowly raised the pod out of its shallow bed.

  When it was about a stride above the hull, Azelio called a halt. They both stood for a moment holding the thing, as if they couldn’t quite believe that it would stay put when they released it. But it did.

  ‘I’ll tow this one out, and you watch over the cable,’ Azelio said.

  ‘Right.’ Agata squatted against the hull and aimed her coherer at the reel. As well as tethering the pod to the pivot it shared with its companion, the cable would carry cooling air to the plants and bring data and video back to the Surveyor.

  Azelio moved into place on the opposite side of the pod; Agata couldn’t see him, so he narrated for her. ‘I’m attaching the towing rope now,’ he said. Then, ‘I’m connected. Be patient, though, this is going to take a while.’

  After a lapse in which nothing happened, Agata asked, ‘Did you fire the jetpack?’

  ‘Yes.’

  ‘I don’t think you’re moving at all.’ The slight tug hadn’t been enough to overcome the sticking friction of the cable; it was prudent to unwind as slowly as possible, but there was a limit to how slow that could be.

  ‘That’s embarrassing.’ Azelio buzzed. ‘All right, a little more thrust this time.’

  The reel began to turn. Agata watched the cable feeding out smoothly, the helix of the outer layer gradually shrinking. Verano’s team had wound every span into place with scrupulous care, and from the flatness of the layers she could see that she wasn’t expecting any hidden snags, but she focused all her attention on the process, refusing to let her mind wander.

  When the cable was down to its last layer and the core of the reel was revealed, Agata advised Azelio and began counting down the remaining turns. Half a turn short of full extension, he brought the pod to a halt. Centrifugal force could complete the process; a tiny amount of slack like this wouldn’t be enough to give the pod a dangerous jolt.

  Agata looked up and waited for her eyes to adjust back to the starlight. The cable stretched out into the void for four or five times the diameter of the hull. With the pod’s stone block hanging on the end of it, her eyes wanted to declare this direction vertical, but when she insisted on her original hull-based definition the sight became even stranger, like a conjurer’s rope trick.

  ‘When you and Ramiro do the spin-up, I want to come out and watch,’ she pleaded.

  ‘If it’s up to me, absolutely,’ Azelio replied. ‘And since you’ve got Tarquinia twisted around your finger—’

  ‘Ha! That’d be something.’ Agata suspected that Tarquinia was listening in on their conversation; for safety’s sake the helmets’ transceivers didn’t use any kind of encryption.

  ‘I’m coming back now.’

  ‘Have you untied the towing rope?’ she asked.

  Azelio was silent for a moment. ‘Good idea.’

  When he’d rejoined her, Agata said, ‘I owe you for this. I was going insane in there.’

  ‘You don’t owe me anything,’ Azelio declared. ‘You sat with me after the link cut off; I haven’t forgotten that.’

  ‘I don’t know if I helped much.’ The children were Azelio’s life; the most she’d been able to do was distract him a little, while the prospect of waiting more than ten years to hear from them again sank in.

  ‘What will we do if Esilio isn’t habitable?’ he asked. They’d switched off their coherers while they talked so as not to dazzle each other, but Agata could make out Azelio’s face in the starlight. She’d come out into the void to escape her dark thoughts, but the cosmic perspective seemed to have had the opposite effect on him. ‘If we go back to them with nothing, it would be like the Peerless returning to the home world with no idea how to escape the Hurtlers.’

  Agata hummed angrily. ‘I don’t believe that. War’s not as inevitable as a Hurtler strike. Anyway . . . when we get to Esilio, we’ll find what we find. No one expects you to work miracles.’

  ‘No.’

  Agata said, ‘We’d better start on the second pod, before Ramiro wakes up and finds out that I’ve stolen half his entertainment.’

  Back at her desk, Agata examined her notes. The truth was that in a year and a half she’d made almost no progress. Now she’d had her frolic beneath the stars; she’d had her Ancestors’ Day celebration. And there was nothing on the calendar to break the monotony until they started up the engines again.

  She could end up squandering half the journey longing for planetfall, and half again longing to be back in the mountain. All her life, this fixation on grand turning points – from the launch of the Peerless to the reunion – had given her a sense of purpose, but it had also weakened and distracted her. Recapitulating the whole thing in miniature had only made the problem more acute. It was only right that the Surveyor’s mission came first, and that she honour Medoro, test Lila’s theory, and play her part in Ramiro’s peace plan. But to make any progress with her own work she had to stop thinking like a passenger: doing no more than clinging on, in the hope that someone else’s flight plan would carry her to a destination worth reaching.

  Agata hadn’t brought a picture of Lila, but she could effortlessly summon the sound of her mentor’s gentle nagging. She knew exactly what Lila’s advice would have been at this juncture: Romolo and Assunto’s tricks weren’t suited to her purpose, and there was no point pretending that some minor variation in their methods would suffice. If she wanted to make progress, she needed to dig far de
eper into the mysteries of the vacuum and come up with some new tools of her own.

  19

  Ramiro passed the first bell of his watch correcting the errors in a small program that he’d written the night before. It computed the shapes of two four-dimensional polyhedra, set them rotating – with different speeds and directions – then displayed a projection of the portion of the first that lay inside the second.

  It was a frivolous exercise, but the endlessly mutating image was strangely soothing, and this playful tinkering did have the advantage that it kept his skills sharp. As much as he’d luxuriated in the process of ridding the Surveyor of its intrusive surveillance software, he’d only been able to prolong that task for about a year, and though he doubted that all the genuinely useful automation that remained would turn out to be ideal for its purpose once they reached Esilio he was still in no better position to know the true requirements than the original designers.

  There was a sudden high-pitched noise from behind him, like something large and brittle being snapped. Not the ominous groan of a machine part under pressure gradually yielding – just instant surrender to an overwhelming force. It was over in a flicker or two, and though the screech itself was unforgettable the lingering impression offered no clues as to its source. Ramiro dimmed the cabin and switched on the exterior lights. Through the window he could see a trail of debris drifting off to his right, small grey rocks spinning in a haze of dust. They could only be fragments of the hull’s hardstone, torn free by a collision of some kind.

  An alarm sounded. The pressure in the Surveyor was dropping.

  He grabbed his helmet and dragged himself back towards the crew’s sleeping quarters. Agata emerged from her room, strapping on her jetpack, helmet in hand. Ramiro could see her tympanum moving but he couldn’t hear a sound; the pressure was already too low. He put on his helmet and she did the same.

  ‘What happened?’ she asked.

  ‘Something’s hit us,’ he said. ‘I don’t know what. Is your cabin holed?’

  ‘No.’

  Ramiro clambered past her and opened the nearest door. There was a jagged slot half a stride across missing from the far wall; the rock along the edges was shattered unevenly, but the course of the damage was unswerving. Sheets of paper were fluttering through the gash, out into the void. Azelio was motionless, tangled in his bed’s twisted tarpaulin. Ramiro approached, switching on his helmet’s coherer to supplement the safety lights, and saw three holes in the tarpaulin, each the width of his thumb.

  Agata’s voice came through the link. ‘Tarquinia’s gone!’

  ‘What?’

  ‘I’m in her cabin – she must have been blown right out.’

  Ramiro stared at Azelio, imagining Tarquinia tumbling through the void in the same condition – carrying no air, insensate, her flesh pierced by splinters of rock.

  ‘I can see sunstone spilling out,’ Agata said. ‘From the cooling system.’

  Ramiro was paralysed. What did he do first? If they couldn’t run the cooling system, they were dead.

  Agata shouted, ‘I can see Tarquinia! I’m going after her!’

  ‘No! I’ll get her!’

  Agata hesitated. ‘You can see her too?’

  ‘No, but—’

  ‘Ramiro, I can do this,’ Agata insisted. She sounded impossibly calm. ‘She’s not that far away, and I can still see her clearly. I’ve got her cooling bag here, air tank and all. I’ll get it to her. She’ll be all right.’

  ‘Yes,’ he agreed. ‘Do it.’

  Agata said nothing more, but then he caught the flash of her coherer as she jetted across the trench of stars behind Azelio’s wall.

  Ramiro shook himself out of his stupor. Azelio’s cooling bag was missing from the clamp beside the bed, but the spare was in the cupboard. He took it over to Azelio and worked it up over his limp form, then he opened the valve on the air tank and held his hand against the fabric to check that there was a flow across the skin. There were five deep wounds in Azelio’s thigh and torso, but his skull seemed to be untouched. The injuries might be survivable – so long as his flesh didn’t denature and ignite.

  Ramiro dragged Azelio into his own cabin; abutting the opposite side of the hull, it appeared to be completely undamaged. He got Azelio under the sand bed’s tarpaulin, and brought two straps across to be sure he wouldn’t drift away.

  ‘You’ll be fine,’ he muttered. ‘You’ll be fine.’

  He dragged himself back into the passage and headed for the cooling system.

  Whatever had grazed the side of the Surveyor had left a single long gash in the hull running all the way from Azelio’s cabin via Tarquinia’s to the gasification chamber. Looking out through the opening where the gash had breached a narrow maintenance shaft, Ramiro could now see what Agata had reported: pieces of sunstone tumbling into the void like gravel spilling from a torn sack. The feed supplying the decomposing agent should have shut off when the pressure plummeted – and if it hadn’t, the result would have been spectacularly worse. But the sunstone would continue to react with the agent already present in the chamber. There was no way to render the swarm of jostling rocks perfectly motionless, so nothing would keep them in the chamber while there was a wide-open path into the void.

  ‘Can you still see Tarquinia?’ he asked Agata.

  ‘I’ve nearly reached her!’ Agata declared. ‘How are things there? Is Azelio all right?’ Once she’d moved away from the Surveyor she would have looked back and taken in all the damage at a glance.

  ‘He’s safe,’ Ramiro assured her. ‘He’s got some small wounds, but I’ve put him in my room to recover. Please, just concentrate on Tarquinia.’

  ‘All right.’

  Ramiro leant against the side of the shaft. How was he going to seal the chamber? They had stone plugs prepared for holes up to the size of his hand, but no one had envisaged anything like this.

  The repair didn’t have to be airtight immediately; he just had to stop the sunstone being lost. He dragged himself to Agata’s cabin and snatched the tarpaulin from her bed, then detoured to the tool cupboard and grabbed a jar of sealing resin.

  If he entered the gasification chamber through the hatch he’d just drive more sunstone out as he pushed his way through it. Back in the maintenance shaft, he warily tested the rim of the gash with one fingertip. The damaged stone was still warm from the collision – with a microscopic Hurtler, most likely – but the escaping air had carried away enough heat to render it traversable. He clambered out into the void and made his way along the torn edge of the hull, hand over hand; the distance was so short that this was faster than messing around with his jetpack.

  ‘I’m with her!’ Agata announced excitedly. ‘She’s conscious, Ramiro. She’s putting on her cooling bag now.’

  Ramiro started humming with relief; embarrassed, he muted the outwards channel on the link until he’d regained his composure. ‘Be careful coming back,’ he managed.

  Agata replied, ‘Don’t worry, we will.’

  As Ramiro climbed into the chamber small pellets of sunstone bounced off his jetpack and faceplate; he had to force himself not to raise his arm instinctively to swat them away like insects, as that would only have added energy to the swarm. He took the jar from his tool pouch and daubed resin over the nearest part of the inner wall, then tugged the tarpaulin out of the gap under his belt and fixed one edge in place. There were no ropes or handholds in the chamber that he could use to brace himself, but he could apply pressure by closing his hand over the whole exposed thickness of the wall, clamping the fabric of the tarpaulin against the resin until it adhered.

  He pushed himself off from the wall to reach the far side of the chamber; he hit it with a jolt but managed to grab the rim of the gash to keep himself from bouncing. The tarpaulin was wider than the gap he was trying to cover, and once he had it secured at both ends the pellets of sunstone were too large to work their way around the sides.

  Ramiro paused to take stock. There was mo
re sunstone in the store behind the chamber; they’d probably only lost about a twelfth of their total. If Tarquinia was safe, the next most urgent matter was checking on Azelio. Getting the gash repaired and the entire Surveyor airtight again would take a long time, but as an interim measure they could seal the doors to the damaged cabins and concentrate on the cooling chamber while they still had enough air in tanks to keep them from hyperthermia.

  He managed to get out of the chamber through the hatch with only a handful of sunstone escaping into the passage. Back in his cabin, he surveyed Azelio’s wounds, cutting holes in the cooling bag so he wouldn’t have to pull the whole thing off. At each site there was a faint yellow glow suffusing the punctured flesh, but it looked like the body’s ordinary signalling rather than a runaway reaction, and the surrounding skin wasn’t hot to the touch. The fragments of stone had passed right through Azelio’s body, but as far as Ramiro could see his digestive tract hadn’t been breached. If his skull and gut were undamaged, his chances were good.

  ‘We’re almost back,’ Agata announced. ‘Ah, you’ve closed off the chamber already!’

  ‘Yes.’ Ramiro had never expected her to prove so indomitable in the face of a calamity like this. One stride deeper into the hull and the Hurtler would have ended the mission. Maybe Agata was relishing the sense of solidarity with the ancestors, and picturing herself as a member of the most far-flung branch of Eusebio’s fire watch.

  The two women returned together through the same opening they’d used to make their separate exits. Ramiro was waiting for them, and he handed Tarquinia her helmet.

  ‘Welcome back,’ he said. If the ordeal had shaken her, she wasn’t letting it show.

  ‘How’s Azelio?’ she asked.

  ‘He’s got five wounds, but they all seem clean to me.’

  ‘Let me take a look.’

  In Ramiro’s cabin, Azelio was still motionless under the tarpaulin, but even from the doorway they could see the light from the wound in his thigh, shining through the fabric.