This is the great moment of my life, Floyd told himself. Now I am leaving on a mission that may determine the future of the human race. But he did not feel any sense of exultation; all he could think of, during the last minutes of the countdown, were the words he had whispered just before he had left home: 'Goodbye, my dear little son; will you remember me when I return?' And he still felt resentment toward Caroline because she would not awaken the sleeping child for one final embrace; yet he knew that she had been wise, and it was better that way.

His mood was shattered by a sudden explosive laugh; Dr Curnow was sharing a joke with his companions – as well as a large bottle that he handled as delicately as a barely subcritical mass of plutonium.

'Hey, Heywood,' he called, 'they tell me Captain Orlova's locked up all the drinks, so this is your last chance. Château Thierry '95. Sorry about the plastic cups.'

As Floyd sipped at the really superb champagne, he found himself cringing mentally at the thought of Curnow's guffaw reverberating all the way across the Solar System. Much as he admired the engineer's, ability, as a travelling companion Curnow might prove something of a strain. At least Dr Chandra would not present such problems; Floyd could hardly imagine him smiling, let alone laughing. And, of course, he turned down the champagne with a barely perceptible shudder. Curnow was polite enough, or glad enough, not to insist.

The engineer was, it seemed, determined to be the life and soul of the party. A few minutes later he produced a two-octave electronic keyboard, and gave rapid renderings of 'D'ye ken John Peel' as performed successively by piano, trombone, violin, flute, and full organ, with vocal accompaniment. He was really very good, and Floyd soon found himself singing along with the others. But it was just as well, he thought, that Curnow would spend most of the voyage in silent hibernation.

The music died with a sudden despairing discord as the engines ignited and the shuttle launched itself into the sky. Floyd was gripped by a familiar but always new exhilaration – the sense of boundless power, carrying him up and away from the cares and duties of Earth. Men knew better than they realized, when they placed the abode of the gods beyond the reach of gravity. He was flying toward that realm of weightlessness; for the moment, he would ignore the fact that out there lay not freedom, but the greatest responsibility of his career.

As the thrust increased, he felt the weight of worlds upon his shoulders – but he welcomed it, like an Atlas who had not yet tired of his burden. He did not attempt to think, but was content to savour the experience. Even if he was leaving Earth for the last time, and saying farewell to all that he had ever loved, he felt no sadness. The roar that surrounded him was a paean of triumph, sweeping away all minor emotions.

He was almost sorry when it ceased, though he welcomed the easier breathing and the sudden sense of freedom. Most of the other passengers started to unbuckle their safety straps, preparing to enjoy the thirty minutes of zero gravity during the transfer orbit, but a few who were obviously making the trip for the first time remained in their seats, looking around anxiously for the cabin attendants.

'Captain speaking. We're now at an altitude of three hundred kilometres, coming up over the west coast of Africa. You won't see much as it's night down there – that glow ahead is Sierra Leone – and there's a big tropical storm over the Gulf of Guinea. Look at those flashes!

'We'll have sunrise in fifteen minutes. Meanwhile I'm rolling the ship so you can get a good view of the equatorial satellite belt. The brightest one – almost straight overhead – is Intelsat's Atlantic-1 Antenna Farm. Then Intercosmos 2 to the west – that fainter star is Jupiter. And if you look just below that, you'll see a flashing light, moving against the star background – that's the new Chinese space-station. We pass within a hundred kilometres, not close enough to see anything with the naked eye -,

What were they up to? Floyd thought idly. He had examined the close-ups of the squat cylindrical structure with its curious bulges, and saw no reason to believe the alarmist rumours that it was a laser-equipped fortress. But while the Beijing Academy of Science ignored the UN Space Committee's repeated requests for a tour of inspection, the Chinese only had themselves to blame for such hostile propaganda.

The "Cosmonaut Alexei Leonov" was not a thing of beauty; but few spacecraft ever were. One day, perhaps, the human race would develop a new aesthetic; generations of artists might arise whose ideals were not based upon the natural forms of Earth moulded by wind and water. Space itself was a realm of often overpowering beauty; unfortunately, Man's hardware did not yet live up to it.

Apart from the four huge propellant tanks, which would be dropped off as soon as the transfer orbit was achieved, Leonov was surprisingly small. From heat shield to drive units was less than fifty metres; it was hard to believe that so modest a vehicle, smaller than many commercial aircraft, could carry ten men and women halfway across the Solar System.

But zero gravity, which made walls and roof and floor interchangeable, rewrote all the rules of living. There was plenty of room aboard Leonov even when everyone was awake at the same time, as was certainly the case at the moment. Indeed, her normal complement was at least doubled by assorted newsmen, engineers making final adjustments, and anxious officials.

As soon as the shuttle had docked, Floyd tried to find the cabin he would share – a year hence, when he awoke – with Curnow and Chandra. When he did locate it, he discovered that it was packed so tightly with neatly labelled boxes of equipment and provisions that entry was almost impossible. He was wondering glumly how to get a foot in the door when one of the crew, launching himself skilfully from handhold to handhold, noticed Floyd's dilemma and braked to a halt.

'Dr Floyd – welcome aboard. I'm Max Brailovsky – assistant engineer.'

The young Russian spoke the slow, careful English of a student who had had more lessons with an electronic tutor than a human teacher. As they shook hands, Floyd matched the face and name to the set of crew biographies he had already studied: Maxim Andreievitch Brailovsky, age thirty-one, born Leningrad, specializing in structure; hobbies: fencing, skycycling, chess.

'Glad to meet you,' said Floyd. 'But how do I get inside?'

'Not to worry,' said Max cheerfully. 'All that will be gone when you wake up. It's – what do you say? – expendables. We'll eat your room empty by the time you need it. I promise.' He patted his stomach.

'Fine – but meanwhile where do I put my things?' Floyd pointed to the three small cases, total mass fifty kilograms, which contained – he hoped – everything he needed for the next couple of billion kilometres. It had been no easy task, shepherding their weightless, but not inertialess, bulk through the ship's corridors with only a few collisions.

Max took two of the bags, glided gently through the triangle formed by three intersecting girders, and dived into a small hatchway, apparently defying Newton's First Law in the process. Floyd acquired a few extra bruises while following him; after a considerable time – Leonov seemed much bigger inside than out– they arrived at a door labelled CAPTAIN, in both Cyrillic and Roman. Although he could read Russian much better than he could speak it, Floyd appreciated the gesture; he had already noticed that all ship's notices were bilingual.

At Max's knock, a green light flashed on, and Floyd drifted inside as gracefully as he could. Though he had spoken to Captain Orlova many times, they had never before met. So he had two surprises.

It was impossible to judge a person's real size over the viewphone; the camera somehow converted everyone to the same scale. Captain Orlova, standing – as well as one could stand in zero gravity – barely reached to Floyd's shoulders. The viewphone had also completely failed to convey the penetrating quality of those dazzling blue eyes, much the most striking feature of a face that, at the moment, could not be fairly judged for beauty.