But he had little time to study Japetus on his way into the heart of the Saturnian system, for the climax of the voyage – Discovery’s last perturbation maneuver – was rapidly approaching. In the Jupiter fly-by, the ship had used the gravitational field of the planet to increase her velocity. Now she must do the reverse; she had to lose as much speed as possible, lest she escape from the Solar System and fly on to the stars. Her present course was one designed to trap her, so that she would become another moon of Saturn, shuttling back and forth along a narrow, two-million-mile-long ellipse. At its near point it would almost graze the planet; at its far one, it would touch the orbit of Japetus.
The computers back on Earth, though their information was always three hours late, had assured Bowman that everything was in order. Velocity and altitude were correct; there was nothing more to be done, until the moment of closest approach.
The immense system of rings now spanned the sky, and already the ship was passing over its outermost edge. As he looked down upon them from a height of some ten thousand miles, Bowman could see through the telescope that the rings were made largely of ice, glittering and scintillating in the light of the Sun. He might have been flying over a snowstorm that occasionally cleared to reveal, where the ground should have been, baffling glimpses of night and stars.
As Discovery curved still closer toward Saturn, the Sun slowly descended toward the multiple arches of the rings. Now they had become a slim, silver bridge spanning the entire sky; though they were too tenuous to do more than dim the sunlight, their myriads of crystals refracted and scattered it in dazzling pyrotechnics. And as the Sun moved behind the thousand-mile-wide drifts of orbiting ice, pale ghosts of itself marched and merged across the sky, and the heavens were filled with shifting flares and flashes. Then the Sun sank below the rings, so that they framed it with their arches, and the celestial fireworks ceased.
A little later, the ship curved into the shadow of Saturn, as it made its closest approach over the night side of the planet. Above shone the stars and the rings; below lay a dimly visible sea of clouds. There were none of the mysterious patterns of luminosity that had glowed in the Jovian night; perhaps Saturn was too cold for such displays. The mottled cloudscape was revealed only by the ghostly radiance reflected back from the circling icebergs, still illuminated by the hidden Sun.
But in the center of the arch there was a wide, dark gap, like the missing span of an uncompleted bridge, where the shadow of the planet lay across its rings.
Radio contact with Earth had been broken, and could not be resumed until the ship emerged from the eclipsing bulk of Saturn. It was perhaps as well that Bowman was too busy now to think of his suddenly enhanced loneliness; for the next few hours, every second would be occupied as he checked the braking maneuvers, already programmed by the computers on Earth.
After their months of idleness, the main thrusters began to blast out their miles-long cataracts of glowing plasma. Gravity returned, though briefly, to the weightless world of the control deck. And hundreds of miles below, the clouds of methane and frozen ammonia blazed with a light that they had never known before, as Discovery swept, a fierce and tiny sun, through the Saturnian night.
At last, the pale dawn lay ahead; the ship, moving more and more slowly now, was emerging into day. It could no longer escape from the Sun, or even from Saturn – but it was still moving swiftly enough to rise away from the planet until it grazed the orbit of Japetus, two million miles out.
It would take Discovery fourteen days to make that climb, as she coasted once more, though in reverse order, across the paths of all the inner moons. One by one she would cut through the orbits of Janus, Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Hyperion – worlds bearing the names of gods and goddesses who had vanished only yesterday, as time was counted here.
Then she would meet Japetus, and must make her rendezvous. If she failed, she would fall back toward Saturn and repeat her twenty-eight-day ellipse indefinitely.
There would be no chance for a second rendezvous if Discovery missed on this attempt. The next time around, Japetus would be far away, almost on the other side of Saturn.
It was true that they would meet again, when the orbits of ship and satellite meshed for a second time. But that appointment was so many years ahead that, whatever happened, Bowman knew he would not witness it.
35 – The Eye of Japetus
When Bowman had first observed Japetus, that curious elliptical patch, of brilliance had been partly in shadow, illuminated only by the light of Saturn. Now, as the Moon moved slowly along its seventy-nine-day orbit, it was emerging into the full light of day.
As he watched it grow, and Discovery rose more and more sluggishly toward her inevitable appointment, Bowman became aware of a disturbing obsession. He never mentioned it in his conversations – or, rather, his running commentaries – with Mission Control, because it might have seemed that he was already suffering from delusions.
Perhaps, indeed, he was; for he had half convinced himself that the bright ellipse set against the dark background of the satellite was a huge, empty eye, staring at him as he approached. It was an eye without a pupil, for nowhere could he see anything to mar its perfect blankness.
Not until the ship was only fifty thousand miles out, and Japetus was twice as large as Earth’s familiar Moon, did he notice the tiny black dot at the exact center of the ellipse. But there was no time, then, for any detailed examination; the terminal maneuvers were already upon him.
For the last time, Discovery’s main drive released its energies. For the last time, the incandescent fury of dying atoms blazed among the moons of Saturn. To David Bowman, the far-off whisper and rising thrust of the jets brought a sense of pride – and of sadness. The superb engines had done their duty with flawless efficiency. They had brought the ship from Earth to Jupiter to Saturn; now this was the very last time that they would ever operate. When Discovery had emptied her propellant tanks, she would be as helpless and inert as any comet or asteroid, a powerless prisoner of gravitation. Even when the rescue ship arrived a few years hence, it would not be an economical proposition to refuel her, so that she could fight her way back to Earth. She would be an eternally orbiting monument to the early days of planetary exploration.
The thousands of miles shrank to hundreds, and as they did so, the fuel gauges dropped swiftly toward zero. At the control panel, Bowman’s eyes flickered anxiously back and forth over the situation display, and the improvised charts which he now had to consult for any real-time decisions. It would be an appalling anticlimax if, having survived so much, he failed to make rendezvous through lack of a few pounds of fuel.
The whistle of the jets faded, as the main thrust died and only the verniers continued to nudge Discovery gently into orbit. Japetus was now a giant crescent that filled the sky; until this moment, Bowman had always thought of it as a tiny, insignificant object – as indeed it was compared with the world around which it circled. Now, as it loomed menacingly above him, it seemed enormous – a cosmic hammer poised to crush Discovery like a nutshell.
Japetus was approaching so slowly that it scarcely seemed to move, and it was impossible to tell the exact moment when it made the subtle change from an astronomical body to a landscape, only fifty miles below. The faithful verniers gave their last spurts of thrust, then closed down forever. The ship was in its final orbit, completing one revolution every three hours at a mere eight hundred miles an hour – all the speed that was required in this feeble gravitational field.
Discovery has become a satellite of a satellite.
36 – Big Brother
“I’m coming round to the daylight side again, and it’s just as I reported on the last orbit. This place seems to have only two kinds of surface material. The black stuff looks burned, almost like charcoal, and with the same kind of texture as far as I can judge in the telescope. In fact, it reminds me very much of burned toast.
“I still can’t make any sense of the white area. It starts at an absolutely sharp-edged boundary, and shows no surface detail at all. It could even be a liquid – it’s flat enough. I don’t know what impression you’ve got from the videos I’ve transmitted, but if you picture a sea of frozen milk you’ll get the idea exactly.