And building new ones. Now indeed mankind had found the 'moral equivalent of war', and a challenge that could absorb the surplus energies of the race – for as many millennia ahead as anyone dared to dream.

When he was born, William Tsung had been called 'the most expensive baby in the world'; he held the title for only two years before it was claimed by his sister. She still held it, and now that the Family Laws had been repealed, it would never be challenged.

Their father, the legendary Sir Lawrence, had been born when China had re-instituted the stringent 'One Child, One Family' rule; his generation had provided psychologists and social scientists with material for endless studies. Having no brothers or sisters – and in many cases, no uncles or aunts – it was unique in human history. Whether credit was due to the resilience of the species or the merit of the Chinese 'extended family' system would probably never be settled. The fact remained that the children of that strange time were remarkably free from scars; but they were certainly not unaffected, and Sir Lawrence had done his somewhat spectacular best to make up for the isolation of his infancy.

When his second child was born in '22, the licensing system had become law. You could have as many children as you wished, provided only that you paid the appropriate fee. (The surviving old guard communists were not the only ones who thought the whole scheme perfectly appalling, but they were outvoted by their pragmatic colleagues in the fledgling congress of the People's Democratic Republic.)

Numbers one and two were free. Number three cost a million sols. Number four was two million. Number five was four million, and so on. The fact that, in theory, there were no capitalists in the People's Republic was cheerfully ignored.

Young Mr Tsung (that was years, of course, before King Edward gave him his KBE) never revealed if he had any target in mind; he was still a fairly poor millionaire when his fifth child was born. But he was still only forty, and when the purchase of Hong Kong did not take quite as much of his capital as he had feared, he discovered that he had a considerable amount of small change in hand.

So ran the legend – but, like many other stories about Sir Lawrence, it was hard to distinguish fact from mythology. There was certainly no truth in the persistent rumour that he had made his first fortune through the famous shoe-box-sized pirate edition of the Library of Congress. The whole Molecular Memory Module racket was an off-Earth operation, made possible by the United States' failure to sign the Lunar Treaty.

Even though Sir Lawrence was not a multitrillionaire, the complex of corporations he had built up made him the greatest financial power on earth – no small achievement for the son of a humble videocassette peddler in what was still known as the New Territories. He probably never noticed the eight million for Child Number Six, or even the thirty-two for Number Eight. The sixty-four he had to advance on Number Nine attracted world publicity, and after Number Ten the bets placed on his future plans may well have exceeded the two hundred and fifty-six million the next child would have cost him. However, at that point the Lady Jasmine, who combined the best properties of steel and silk in exquisite proportion, decided that the Tsung dynasty was adequately established.

It was quite by chance (if there is such a thing) that Sir Lawrence became personally involved in the space business. He had, of course, extensive maritime and aeronautical interests, but these were handled by his five sons and their associates. Sir Lawrence's real love was communications – newspapers (those few that were left), books, magazines (paper and electronic) and, above all, the global television networks.

Then he had bought the magnificent old Peninsular Hotel, which to a poor Chinese boy had once seemed the very symbol of wealth and power, and turned it into his residence and main office. He surrounded it by a beautiful park, by the simple expedient of pushing the huge shopping centres underground (his newly formed Laser Excavation Corporation made a fortune in the process, and set a precedent for many other cities).

One day, as he was admiring the unparalleled skyline of the city across the harbour, he decided that a further improvement was necessary. The view from the lower floors of the Peninsular had been blocked for decades by a large building looking like a squashed golfball. This, Sir Lawrence decided, would have to go.

The Director of the Hong Kong Planetarium – widely considered to be among the five best in the world – had other ideas, and very soon Sir Lawrence was delighted to discover someone he could not buy at any price. The two men became firm friends; but when Dr Hessenstein arranged a special presentation for Sir Lawrence's sixtieth birthday, he did not know that he would help to change the history of the Solar System.

More than a hundred years after Zeiss had built the first prototype in Jena in 1924, there were still a few optical planetarium projectors in use, looming dramatically over their audiences. But Hong Kong had retired its third-generation instrument decades ago, in favour of the far more versatile electronic system. The whole of the great dome was, essentially, a giant television screen, made up of thousands of separate panels, on which any conceivable image could be displayed.

The programme had opened – inevitably – with a tribute to the unknown inventor of the rocket, somewhere in China during the thirteenth century. The first five minutes were a high-speed historical survey, giving perhaps less than due credit to the Russian, German and American pioneers in order to concentrate on the career of Dr Hsue-Shen Tsien. His countrymen could be excused, in such a time and place, if they made him appear as important in the history of rocket development as Goddard, von Braun, or Koroylev. And they certainly had just grounds for indignation at his arrest on trumped-up charges in the United States when, after helping to establish the famed Jet Propulsion Laboratory and being appointed Caltech's first Goddard Professor, he decided to return to his homeland.

The launching of the first Chinese satellite by the 'Long March 1' rocket in 1970 was barely mentioned, perhaps because at that time the Americans were already walking on the Moon. Indeed, the rest of the twentieth century was dismissed in a few minutes, to take the story up to 2007 and the construction of the spaceship Tsien.

The narrator did not gloat unduly over the consternation of the other spacefaring powers, when a presumed Chinese space station suddenly blasted out of orbit and headed for Jupiter, to overtake the Russian-American mission aboard the Cosmonaut Alexei Leonov. The story was dramatic – and tragic – enough to require no embellishment.

Unfortunately, there was very little authentic visual material to illustrate it: the programme had to rely largely on special effects and intelligent reconstruction from later, long-range photo-surveys. During their brief sojourn on the icy surface of Europa, Tsien's crew had been far too busy to make television documentaries, or even set up an unattended camera.

Nevertheless, the words spoken at the time conveyed much of the drama of that first landing on the moons of Jupiter. The commentary broadcast from the approaching Leonov by Heywood Floyd served admirably to set the scene, and there were plenty of library shots of Europa to illustrate it:

'At this very moment I'm looking at it through the most powerful of the ship's telescopes; under this magnification, it's ten times larger than the Moon as you see it with the naked eye. And it's a really weird sight.