But it had been over in minutes, leaving a handful of survivor ships, all in Chinese hands. Ferries had come out from Ceres to take survivors off the wrecks. And meanwhile tugs had sailed out to drag the operational ships into a quickly improvised dry dock, just a big scaffolding frame in space, where they used the UN craft to build – something else.
‘It’s fantastically crude,’ Trant said. ‘You can see what they did, just lined up the hulks in a bank, side by side, coupled them with these struts here. Parallel burners. But each burner is a fully fledged interplanetary kernel-powered hulk ship.’
‘And this is the Nail.’
‘That’s right. We don’t know if it’s crewed or not. Probably it is; there wouldn’t have been time to automate the thing fully before it was fired off, just hours after the battle was concluded. A kamikaze mission, right? They evidently planned this, even before they boarded the ISF ships, they prepared for it, they had everything ready. Probably work continued on the combined craft even after launch out of Ceres, although that would have been difficult under the one-gravity thrust that prevailed.’
‘One gravity?’
‘Yes. And they’ve kept that up for more than three days. Look at this trajectory chart . . .’ She tapped her slate.
It took Mardina a moment to understand what she was seeing: five concentric circles centred on a yellow disc, a straight line cutting across from the fifth circle out from the centre to the innermost.
‘This is the solar system,’ Monica Trant said. ‘Obviously. The paths of the planets, out to Ceres. Just schematic, but the markings show the planets’ current relative positions in their orbit. And this straight line—’
‘The trajectory of the Nail.’ Mardina was old enough to have been brought up on pre-kernel, pre-hulk spacecraft trajectories. Low-energy trajectories followed sections of ellipses, orbits like the planets’; you glided powerless along a curve from one world to the next, with a minor blip of a rocket engine at either end. A hulk ship, though, a craft that could accelerate at a whole gravity for days, weeks on end, crossed interplanetary space in straight lines. ‘You know, I worked in astronavigation. On a starship, for God’s sake. But we never drove a hulk ship across the solar system. We never made tracks like this.’ Mardina counted the orbits. ‘And this is the Nail’s trajectory. From Ceres straight to Mercury.’
‘Damn right.’
Mardina tried to remember her astronomical distances; Ceres was over two astronomical units out from the sun, more than twice as far as Earth, whereas Mercury was less than half an AU out. You had the relative positions in their orbits to take account of too. But after three days at constant one-G acceleration –
She looked at Trant, horrified. ‘It must be nearly here.’
‘Only hours away. It’s been on a straight-line track for Mercury, indeed for this location on Mercury, this facility, since it was launched. The projections show it clearly. And it hasn’t deviated once.
‘I think they’ve decided to take out the Caloris facility – the kernel-processing facilities, maybe even the Hatch. It’s kind of dog-in-the-manger; if we won’t share the kernel tech then nobody gets to use it. But there are precedents. In the past, states, or even organisations like the UN, have mandated strikes against rogue states to take out nuke facilities, for instance, before they had a chance to be used . . .’
Even faced with this blunt revelation, Mardina found it hard to take in. She’d heard hints of a threat to Mercury, the kernel plants, something coming this way. That had been enough for her to ship Beth as far out of the inner system as she could. But she’d imagined some kind of invasion, an attempt to take the Caloris base. She’d never imagined anything like this attempt at wilful destruction. ‘They’ve been in flight three days. They must have been seen by UN surveillance systems. Why has there been no warning to the staff?’
Trant pulled a face, weary, cynical. ‘This is a UEI facility. The UEI has a habit of secrecy. Anyhow, we thought it was a bluff. We thought they’d pull away, veer off after giving us a scare, having shown us what they can do. I guess they might still.’
‘But you’ve decided not to bank on it. And that isn’t some damn V-2.’ Again she tried to figure the numbers in her head. ‘After three days at a full G, they must be travelling at—’
‘About one per cent the speed of light. And those hulk ships are pretty massive. That’s a lot of kinetic energy.’
‘It’s a relativistic missile, is what it is. And they’ve unleashed it in the middle of the inner solar system? How could they even think of this?’
Monica Trant took her shoulders and stared in her face. ‘Mardina, the whole future of mankind pivots on this moment, these few hours and days. That’s how they can think of this. If they lose this game, they’ve lost for ever, because we’d have a monopoly on the kernels. Maybe we’d do the same, if the position was reversed. Probably would. You feel outrage? I feel outrage. Keep it for later. Meanwhile we have to get to one of the transports; they’re not going to wait.’
Something in Mardina broke at last. They started to run for the exit from the dome.
‘I’m sorry,’ she called to Trant. ‘I kept you behind.’
‘Don’t sweat it. You were concerned for your girl. I’m a mother too. My son’s on Earth, in one of the new northern cities.’
‘The Earth’s supposed to be protected—’
‘That’s the theory.’
‘Do you think he’ll be safe?’
Monica Trant shrugged as she ran, stiffly. ‘Rob’s a cop. They get weapons, the first pick of the available food, shelter. If he’s not safe down there nobody is.’
They reached a port in the dome wall, a surface tunnel leading to a transport craft out of here. But there was a crowd already here, a queue in the tunnel. Trant flashed a rank card to force their way through the line, but soon the people were jammed in so tight there was no way to get forward except to shuffle along with the herd.
People: they were all around Mardina, ISF crew and UEI personnel, scientists and administrators, mechanics and cooks and cleaners, the whole community that had sustained itself under this dome, all draining towards a handful of airlocks like this one, trying to escape. Children too, lanky low-gravity children born in a dome under the solar fire during their parents’ long-duration stays here on Mercury. Mardina had spent only a short time here since returning from Earth, but she was surprised how many she recognised. People: each one a fully rounded consciousness, each with a past, memories, hopes for the future, each with a mesh of family and friends and enemies, loves and loyalties, rivalries and hatreds. All jammed up arbitrarily in this tube like overflow baggage, with a relativistic missile coming down on their heads.
Trant murmured, ‘We’re using every which way to get out of here. If we make it out at all, we’ll be loaded onto a surface-to-surface bug. Even that has enough push to get us off the planet at least, for pick-up later. Any way to get people off the surface and scattered, we’re using. We’re even piling people into cargo pods and using the mass driver.’
Mardina, even as they worked their way through the crush, was still trying to figure out the implications of this assault. ‘The Nail is coming right down on top of the facility, right? Which itself sits on top of the densest concentration of kernels, and the Hatch structure itself.’
‘That’s right.’
‘So what’s the Nail going to do to the planet?’
Trant shrugged. ‘We don’t have good models. Partly because nobody took it seriously, despite the Chinese sending us endless warnings to evacuate. And since people have started taking it seriously, we’ve all been too busy running. At least a major impact; one of our experts thinks it will be like another Caloris. Which was a punch that created a crater that spanned one whole hemisphere, with a rebound at the antipode where waves in the surface rock converged. Which is why we want to get everybody off the planet altogether, if we can, even if it’s going to be a heck of a retrieval operation later.’