Captain Dimitri Chandler [M2973.04.21/93.106//Mars//I SpaceAcad3005] – or 'Dim' to his very best friends – was understandably annoyed. The message from Earth had taken six hours to reach the space-tug Goliath, here beyond the orbit of Neptune; if it had arrived ten minutes later he could have answered 'Sorry – can't leave now – we've just started to deploy the sun-screen.'

The excuse would have been perfectly valid: wrapping a comet's core in a sheet of reflective film only a few molecules thick, but kilometres on a side, was not the sort of job you could abandon while it was half-completed.

Still, it would be a good idea to obey this ridiculous request: he was already in disfavour sunwards, through no fault of his own. Collecting ice from the rings of Saturn, and nudging it towards Venus and Mercury, where it was really needed, had started back in the 2700s – three centuries ago. Captain Chandler had never been able to see any real difference in the 'before and after' images the Solar Conservers were always producing, to support their accusations of celestial vandalism. But the general public, still sensitive to the ecological disasters of previous centuries, had thought otherwise, and the 'Hands off Saturn!' vote had passed by a substantial majority. As a result, Chandler was no longer a Ring Rustler, but a Comet Cowboy.

So here he was at an appreciable fraction of the distance to Alpha Centauri, rounding up stragglers from the Kuiper Belt. There was certainly enough ice out here to cover Mercury and Venus with oceans kilometres deep, but it might take centuries to extinguish their hell-fires and make them suitable for life. The Solar Conservers, of course, were still protesting against this, though no longer with so much enthusiasm. The millions dead from the tsunami caused by the Pacific asteroid in 2304 – how ironic that a land impact would have done much less damage! – had reminded all future generations that the human race had too many eggs in one fragile basket.