Now.

Deuterium droplets sprayed into the freezer chamber, where they froze, and next were electrostatically coated with tritium dust. A ring of injectors then fired the resultant microspheres into the main chamber. Once a sphere reached the chamber’s centre, it was captured in a twenty tesla magnetic bottle, then briefly enclosed in a hardfield case, open on one side and with just enough gaps in it to allow access for the beams of high-intensity stacked gallium-arsenide lasers. The lasers fired, igniting fusion, then this process repeated a hundredth of a second later, and kept on repeating. The resultant helium plasma contained less than.00001 isotope contamination, but was still dangerously destructive.

White fire stabbed out of the open side of the hardfield box, and then out of the layered ceramo-carbide combustion chamber. It cut through rooms previously occupied, converted walls, floors, ceilings, coffee tables and sofas to incandescent gas, and blasted out into vacuum. Spearing out from the station edge, it burned red-orange. Mr exploded into space, wreckage followed. The conglomeration of structures peeled away, burst asunder, was flung away by the station’s spin. Celedon noted fire alarms and systems coming online, and going off just as quickly as they collapsed. And then Celedon, the station, slowly began to tilt.

Shutdown.

The fire went out. In two hours’ time a stabilizing burn would be required from rim engine 4, which gave the Golem plenty of time to clear out the last sixty people still within its vicinity. Gazing internally Celedon observed the outlinkers releasing themselves from wall-holds after acceleration ceased. They had not liked that sensation at all, but it made them move much faster towards Runcible A.

Celedon separated out one of the many communications sent to it and replied ‘Forty-seven hours’ to Draesil’s query. Shaking his head in annoyance, the man himself followed a group of outlinker children through the runcible.

Two hours later, the AI initiated the stabilizing burn. The station now pointed directly at what was, by a very roundabout route, its intended destination. Forty-five hours after that, with the station finally emptied of fragile organic life, Celedon turned on the main fusion engine, and shed the accretions on the station’s surface like an old skin. Then, after a three-hour burn followed by a shutdown, the AI again used the rim engines to adjust the station’s attitude before reigniting the main drive. Now, rather than pursue a long curving roundabout route to the destination sun, the station took the most direct route possible taking into account its original velocity. The journey commencing would take three years, but this would not matter to the original sender of the information package. For once Celedon initiated full connection to the sending runcible, the time there, in the future, would not have changed at all.

Deuterium and tritium canisters arrived through Runcible D and the skeletal Golem manhandled them to the monorail train, out of which they had already torn all the furnishings to convert it into a fuel transporter. While they ran this extra fuel down to the main engine, Celedon watched through the eyes of the hundreds of maintenance robots swarming in the sector of the station containing Runcible A. That sector, shaped like a wedge with the tip cut off, was originally devised to be ejected from the station in the event of catastrophic runcible failure. However, over the years, bulkheads had been removed, doors added, its internal structure changed. Supervised by Arach, robots brought out sheets of ceramal-laminated composite from a factory located in the central spindle, to deliver to other robots who powder-welded them into place. Still other robots cut through any structural members Celedon calculated to be unnecessary, leaving only those necessary under the five-G deceleration down towards the green sun. To those remaining structural members holding the sector to the station, Celedon sent Fly to attach planar explosives. These bombs would generate a disc-like explosion which would sever the retaining members nicely.

‘The Jerusalem will be joining you in seventy-three days,’ Earth Central informed the AI abruptly.

‘Should I wait?’ Celedon enquired. ‘I’m only fifty-one days away from achieving low solar orbit.’

‘You should indeed wait. This will give you time to complete your preparations.’

‘My preparations will be completed by the time I achieve low solar orbit.’

‘No they will not,’ EC replied, and followed that pronouncement with an information package.

Celedon scanned the package, learning only now about certain recent events in the Polity and the Jerusalem AI’s involvement in them. Necessarily it both reviewed and looked towards updating many security procedures. Ejecting the A sector of the station was just part of this adjusted hostile contact protocol. The original package had made it aware it must prepare itself for the possibility of attack by Jain technology—a particularly nasty subversive technology left lying around by a long-dead alien race—but now this extra information made it realize precisely what that could mean. As much as an AI could be, Celedon was scared.

First the A sector: station spin alone would not be enough to eject it fast enough. After Fly finished placing the planar explosives, Celedon sent the drone to place other explosives around the inner spindle bulkhead. Once the sector detached, these too could be detonated. The air from inside the sector would then blast out, driving it even further from the station. Fortunately this sector also had a rim motor, which was self-contained but for the controlling optic feed. Fly severed that feed and installed a module to enable that motor to be activated by radio.

‘So I must accept the possibility of Jain-controlled humans?’ Celedon idly asked EC.

‘You must, so take what precautions you can.’

Celedon allowed itself the equivalent of a wince. Doubtless Jerusalem would deal with the problem, should Jain technology board the station via that route. The station, and Celedon itself, would certainly not survive the experience.

The corridor running directly from the runcible, through an airlock into sector B, was already ready. Celedon therefore directed Fly and a hundred Golem to start building an isolation area in B. Necessarily, the surrounding areas were hardened to worm and viral attack, so the AI’s only access would be via narrowband voice and video transmission routed through five relays, all of them outside the station, all of them rigged for detonation, and targeted by masers on the rim. Sector A, however, the AI now isolated but for its link to Arach, and to runcible control, which was utterly necessary. The AI felt that the risk of Jain subversion of itself through the former communications route to be outweighed by the inherent risks of not knowing what was going on. The safest option, of course, would be to not allow initiation of any full transmission from that future runcible. But Earth Central commanded and Celedon obeyed. Obviously, further vital information might become available from that transmission.

Fifty-one days later, Celedon fell into orbit around the green sun, some distance inside the orbit of its one Venusian planet. As the temperature climbed, the station’s AI routed heat through superconducting cables to thermal generators on its dark side, where gas lasers then emitted it into vacuum. On the sixtieth day a solar flare arched below, and the side of the station turned to the sun became too radioactive to support human life. But the AI had foreseen this possibility. The A sector, containing Runcible A, now lay away from the solar furnace, and would only be turned towards it at the last possible moment. Precisely on time, on the seventy-third day, Celedon detected a U-space disturbance a million miles out in space, as the titanic Jerusalem folded into existence: a spherical research vessel three miles in diameter with a thick band around its equator containing everything from legions of robotic probes up to U-space tugs and grabships, and weapons.