“We are now on cruise mode at one-fifth gee. Passengers may unstrap themselves and move about freely-but please use caution until you are completely adapted.”

That won’t take me very long, thought Duncan as be unbuckled himself; the ship’s acceleration gave him his normal, Titan weight. Any residents of the

Moon would also feel completely at home here, while Martians and

Terrans would have a delightful sense of buoyancy. The lights in the lounge, which had been dimmed almost to extinction for better viewing of the spectacle outside, slowly brightened to normal. The few first magnitude stars that had been visible disappeared at once, and the gibbous globe of Saturn became bleached and pale, losing all its colors.

Duncan could restore the scene by drawing the black curtains around the observation alcove, but his eyes would take several minutes to readapt. He was wondering whether to make the effort when the decision was made for him.

There was a musical “Ding-dong-ding,” and a new voice, which sounded as if it came from a social stratum several deLyrees above the Captain’s, anuounced languidly: “This is the Chief Steward. Will passengers kindly note that First Seating for lunch is at twelve hundred, Second Seating at thirteen hundred, Last Seating at fourteen hundred. Please do not attempt to make any changes without consulting me. Thank you.” A less peremptory

“Dong-ding-dong” signaled end of message.

Looking at the marvels of the universe made you hungry, Duncan instantly discovered. It was already 1150,“and he was glad that he was in the First

Seating. He wondered how many starving passengers were now converging upon the Chief Steward, in search of an earlier time slot.

Enioyin!~ the sensation of man-made weight which, barrina accidents, would remain constant until the moment of mid-voyage, Duncan went to join the rapidly lengthening line at the cafeteria.

Already, his first thirty years of life on Titan seemed to belong to

another existence.

LAST WORDS

For onemomentmore, the achingly familiar image remained frozen on the screen. Behind Marissa and the children, Duncan could see the two armchairs of the living room, the photograph of Grandfather (as usual, slightly askew), the cover of the food distribution hatch, the door to the main bedroom, the bookcase with the few but priceless treasures that had survived two centuries of interplanetary wandering…. This was his universe. It held everything he loved, and now he was leaving it.

Already, it lay in his past

It lay only three seconds away, yet that was enough. He had traveled a mere million kilometers in less than half a day; but the sense of separation was already almost complete. It was intolerable to wait six seconds for every reaction and every answer. By the time a reply came, he had forgotten the original question and had started to say something else. And so the attempted conversation had quickly degenerated into a series of stops and starts, while he and Marissa had stared at each other in dumb misery, each waiting for the other to speak…. He was glad that the ordeal was over.

The experience brought home to him, as nothing else had yet done, the sheer immensity of space. The Solar System, he began to suspect, was not designed for the convenience of Man, and that presumptuous creature’s attempts to use it for his own advantage would often be foiled by laws beyond his control. All his life, Duncan had assumed without question that he could speak to friends or family instantly, wherever he might be. Yet now-before he had even passed Saturn’s outer

moons!-that power had been taken from him. For the next twenty days, he would share a lonely, isolated bubble of humanity, able to interact with his fellow passengers, but cut off from all real contact with the rest of mankind.

His self-pity lasted only a few moments. There was also an exhilaration—even a freedom-in this sense of isolation, and in the knowledge that he was setting forth on one of the longest and swiftest voyages that any man could make. Travel to the outer planets was routine and uneventful-but it was also rare, and only a very small fraction of the human race would ever experience it. Duncan remembered a favorite Terran phrase of Malcolm’s, usually employed in a different context, but sound advice for every occasion: “When it’s inevitable, relax and enjoy it.” He would do his best to enjoy this voyage.

Yet Duncan was exhausted when he finally climbed into his bunk at the end of his first day in space. The strain of innumerable farewells, not only to his family but to countless friends, had left him emotionally drained. On top of this, there were all the nagging worries of departure: What had he forgotten to do? What vital necessities had he failed to pack? Had all his baggage been safely loaded and stowed? What essential good-byes had he overlooked? It was useless worrying about these matters now that he was speeding away from home at a velocity increasing by twenty-five thousand kilometers an hour, every hour, yet he could not help doing so. Tired though he was, his hyperactive brain would not let him sleep.

It takes real genius to make a bed that can be uncomfortable at a fifth of a gravity, and luckily the designers of Sirius had not accepted this challenging assignment. After thirty minutes or so, Duncan began to relax and to get his racing thoughts in order. He prided himself on being able to sleep without artificial aids, and it looked as if he would be able to dispense with electro narcosis after all. That was, of course, supposed to be completely harmless, but he never felt pronerly awake the next day.

You’re’falling asleep, he told himself. You won’t know anything more until it’s time for breakfast. All your dreams are going to be happy

ones…. A sound like a small volcano clearing its throat undid the good work of the last ten minutes. He was instantly wide awake, wondering what disaster had befallen Sirius. Not until several anxious seconds had passed did he realize that some antisocial shipmate had found it necessary to visit the adjacent toilet.

Cursing, he tried to recapture the broken mood and to return to the threshold of sleep. But it was useless; the myriad voices of the ship had started to clamor for his attention. He seemed to have lost control of the analytical portion of his brain, and it was busy classifying all the noises from the surrounding universe.

It had been hours since he had really noticed the far-off, ghostly whistling of the drive. Every second Sirius was ejecting a hundred grams of hydrogen at a third of the velocity of light-a trifling loss of mass, yet it represented meaningless millions of gigawatts. During the first few centuries of the Industrial Revolution, all the factories of Earth could not have matched the power that was now driving him sunward.

That incongruously faint and feeble scream was not really disturbing, but it was overlaid with all. sorts of other peculiar sounds. What could possibly cause the “Buzz… click, click … buzz,” the soft “thump … thump … thump,” the “gurgle, hissssss,” and the intermittent “whee-wheee-whee” which was the most maddening of all?

Duncan rolled over and tried to bury. his head in the pillows. It made no difference, except that the higher-pitched sounds got filtered out and the lower frequencies were enhanced. He also became more aware of the steady pulsation of the bed itself, at just about the ten cycles per second nicely calculated to produce epileptic fits.

Hello, that was something new. It was a kind of dispirited kerplunk, kerplunk, kerplunk” that might have been produced by an ancient internal combustion engine in the last stages of decrepitude. Somehow, Duncan seriously doubted that i.c. engines, old or new, were to be found aboard

Sirius. He rolled over on the other side-and then became conscious of the slightly cold airstream from the ventilator hitting him on his left cheek. Perhaps if he ignored it, the sensation would sink below the threshold of consciousness. However, the very effort of pretending it wasn’t there focused attention upon the annoyance.