System.

In a few hours, that precious cargo would be falling sunward, past Saturn’s other-moons, past giant Jupiter, to make its rendezvous with

one of the fueling stations that circled the inner planets. It would take months-even years-to get there, but there was no hurry. As long as cheap hydrogen flowed through the invisible pipeline across the Solar System, the fusion rockets could fly from world to world, as once the ocean liners had plied the seas of Earth.

Duncan understood this better than most boys of his age; the hydrogen economy was also the story of his family, and would dominate his own future when he was old enough to play a part in the affairs of Titan. It was now almost a century since Grandfather Malcolm had realized that Titan was the key to all the planets, and had shrewdly used this knowledge for the benefit of mankind-and of himself.

So Duncan continued to listen to the recording after Karl had switched off.

Over and over again he played back that triumphant, cry of power, trying to detect the precise moment when it was finally swallowed up in the gulfs of space. For years it would haunt his dreams; he would wake in the night, convinced that he had heard it again through the roof of rock that protected Oasis from the hostile wilderness above.

And when at last he fell back into sleep, he would always dream of Earth.

DYNASTY

Malcolm Makenzie had been the right man, at the right time. Others before him had looked covetously at Titan, but he was the first to work out all the engineering details and to conceive the total system of orbiting scoops, compressors, and cheap, expendable tanks that could hold their liquid hydrogen with minimum loss as they dropped leisurely sunward.

Back in the 2180’s, Malcolm had been a promising young aerospace

designer at Port Lowell, trying to make aircraft that could carry useful payloads in the tenuous Martian atmosphere. In those days he had been Malcolm Mackenzie, for the computer mishap that had irrevocably changed the family name did not occur until he emigrated to Titan. After wasting five years in futile attempts at correction, Malcolm had finally cooperated with the inevitable. It was one of the few battles in which the Makenzies had ever admitted defeat, but now they were quite proud of their unique name.

When he had finished his calculations and stolen enough drafting-computer time to prepare a beautiful set of drawings, young Malcolm had approached the Planning Office of the Martian Department of Transportation. He did not anticipate serious criticism, because he knew that his facts and his logic were impeccable.

A large fusion-powered space liner could use ten thousand tons of hydrogen on a single flight, merely as inert working fluid. Ninety-nine percent of it took no part in the nuclear reaction, but was hurled from the jets unchanged, at scores of kilometers a second, imparting momentum to the ships it drove between the planets.

There was plenty of hydrogen on Earth, easily available in the oceans; but the cost of lifting megatons a year into space was horrendous. And the other inhabited worlds-Mars, Mercury, Ganymede, and the Moon-could not help. They had no surplus hydrogen at all.

Of course, Jupiter and the other Gas Giants possessed unlimited quantities of the vital element, but their gravitational fields guarded it more effectively than any unsleeping dragon, coiled round some mythical treasure of the Gods. In all the Solar System, Titan was the only place where Nature had contrived the paradox of low gravity and an atmosphere remarkably rich in hydrogen and its compounds.

Malcolm was right in guessing that no one would challenge his figures, or deny the feasibility of the scheme, but a kindhearted senior administrator took it upon himself to lecturp young Makenzie on the

political and economic facts of life. He learned, with 7 remarkable speed, about growth curves and forward discounting and interplanetary debts and rates of depreciation and technological obsolescence, and understood for the first time why the solar was backed, not by gold, but by kilowatt-hours.

“It’s an old problem,” his mentor had explained patiently. “In fact, it goes back to the very beginnings of astronautics, in the twentieth century.

We couldn’t have commercial space flight until there were flourishing extraterrestrial colonies-and we couldn’t have colonies until there was commercial space transportation. In this sort of bootstrap situation, you have a very slow growth rate until you reach the takeoff point. Then, quite suddenly, the curves start shooting upward, and you’re in business.

“It could be the same with your Titan refueling scheme-but have you any idea of the initial investment required? Only the World Bank could possibly underwrite it….”

“What about the Bank of Selene? Isn’t it supposed to be more adventurous?”

“Don’t believe all you’ve read about the Gnomes of Aristarchus; they’re as careful as anyone else. They have to be. Bankers on Earth can still go on breathing if they make a bad investment …… But it was the Bank of Selene, three years later, that put up the five megasols for the initial feasibility study. Then Mercury became interested-and finally Mars.” By this time, of course, Malcolm was no longer an aerospace engineer. He had become, not necessarily in this order, a financial expert, a public-relations adviser, a media manipulator, and a shrewd politician. In the incredibly short time of twenty years, the first hydrogen shipments were falling sunward from Titan.

Malcolm’s achievement had been an extraordinary one, now well documented in dozens of scholarly studies, all respectful, though some of them far from flattering. What made it so remarkable-even unique was the way in which he had converted his hard-won expertise from technology to administration. The process had been so imperceptible that no one realized what was happening.

Malcolm was not the first engineer to become a head of state; but he

was the first, a his critics pointed out sourly, to establish a dynasty. And he had done so against odds that would have daunted lesser men.

In 2195, at the age of forty-four, he had married Ellen Killner, recently emigrated from Earth. Their daughter, Anitra, was the first child to be born in the little frontier community of Oasis, then the only permanent base on

Titan, and it was several years before the devoted parents realized the cruel jest that Nature had played upon them.

Even as a baby, Anitra was beautiful, and it was confidently predicted that when she grew up she would be completely spoiled. Needless to say, there were as yet no child psychologists on Titan; so no one noticed that the little girl was too docile, too well behaved-and too silent. Not until she was almost four years old did Malcolm and Ellen finally accept the fact that Anitra would never be able to speak, and that there was really no one at home in the lovely shell their bodies had fashioned.

The fault lay in Malcolm’s genes, not Ellen’s. Sometime during his shuttling back and forth between Earth and Mars, a stray photon that had been cruising through space since the cosmic dawn had blasted his hopes for the future. The damage was irreparable, as Malcolm discovered when he consulted the best genetic surgeons of four worlds. It was a chilling thought that he had actually been lucky with Anitra; the results could have been far, far worse…. To the mingled sorrow and relief of an entire world, Anitra had died before she was six years old, and the Makenzie marriage died with her in a flurry of grief and recrimination. Ellen threw herself into her work, and Malcolm departed on what was to be his last visit to Earth. He was gone for almost two years, and in that time he achieved much.

He consolidated his political position and set the pattern of economic development on Titan for the next half-century. And he acquired the son he had now set his heart upon.