Draesil nodded and pushed himself away from the wall, speaking into his collar comlink as he tumbled freely through the air. ‘This is the real thing, people. We have fifty hours to get out of here. Grab your stuff and head for Runcible A.’

Celedon then turned its attention to other matters, glad that at least the humans in this small section of the station had become someone else’s headache. Seven hundred and thirty people had already gone through the runcibles. The lounges of D and E were becoming very crowded, but now the spider and the pill bug arrived and began directing people to the monorails which would take them around the station’s main disc to the other runcibles opening up. The alacrity with which the crowd obeyed those drones, Celedon put down to atavistic fears: few humans would be inclined to disobey the orders of an iron spider with a leg-span of three yards.

Now, the engines. The main fusion engine lay along the axis of the station, protruding into space below it, so was free to fire up at any time, but Celedon needed to utilize the rim engines now. It observed one area, positioned over one of those four engines, now clear of human occupants, and Golem in the process of leaving too. Celedon began closing the airlocks, but then, after noting something through its cameras, reopened a lock and sent one of the Golem back inside. It shortly returned carrying a large fat cat under its arm, which it handed to a distraught woman who came running back to collect it. Celedon emitted a silicon sigh and closed the final airlock.

The rim engines were of an old design fuelled by deuterium and tritium microspheres. Their tanks were full of liquid deuterium and tritium talc, and had been so for a hundred years. Diagnostics detected no faults, therefore this particular engine stood ready to ignite, but not yet. The Celedon station possessed a slight spin, not for centrifugal gravity, that problem having been overcome long ago with gravplates, but to fling away any docked spacecraft—though the last one of those had departed thirteen years ago. Checking with an astrogation program, the controlling AI, Celedon, waited the required twenty-two minutes and seven seconds.

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.