Arthur Clarke: A Meeting with Medusa

He never lost consciousness, but then, he had not expected to. Kon-Tiki trailed through the Jovian atmosphere must be really spectacular by this time, thousands of miles long. Five hundred seconds after entry, the drag began to taper off, ten g, five g, two… Then weight vanished almost completely. He was falling free, all his enormous orbital velocity destroyed.

There was a sudden jolt as the incandescent renmants of the heat shield was jettisoned. It had done its work and would not be needed again, Jupiter could have it now. He released all but two of the restraining buckles, and waited br the automatic sequencer to start the next, and most critical, series of events.

He did not see the first drogue parachute pop out, but he could feel the slight jerk, and the rate of fall diminished imnediately. Kon-Tiki had lost all its horizontal speed and was going straight down at almost a thousand mi1es an hour. Everything depended on what happened in the next sixty seconds.

There went the second drogue. He looked up through the overhead window and saw, to his immense relief, that clouds of glittering foil were billowing out behind the falling ship. Like a great flower unfurling, the thousands of cubic yards of the balloon spread out across the sky, scooping p the thin gas until it was fully inflated. Kon-Tiki’s rate of fall dropped to a few miles an hour and remained constant. Now there was plenty of time, it would take him days to fall all the way down to the surface of Jupiter.

But he would get there eventually, even if he did nothing about it. The balloon overhead was merely acting as an efficient parachute. It was poviding no lift, nor could it do so, while the gas inside and out was the same.

With its characteristic and rather disconcerting crack the fusion reactor started up, pouring torrents of heat into the envelope overhead. Within five minutes, the rate of fall had become zero; within six, the ship had started to level. According to the radar altimeter, it had levelled out at about two hundred and sixty-seven miles above the surface, or whatever passed for surface on Jupiter.

Only one kind of balloon will work in an atmosphere of hydrogen, which was the lightest of all gases and that is a hot-hydrogen balloon. As long as the fusion reacter kept ticking over, Falcon could remain aloft, drifting across a world that could hold a hundred Pacifics. After travelling over three hunndred million miles, Kon-Tiki had at last begun to justify her name. She was an aerial raft, adrift upon the currents of the Jovian atmosphere.

Though a whole new world was lying around him, it was more than an hour before Falcon could examine the view. First he had to check all the capsule’s systems and test its response to the controls. He had to learn how much extra heat was necessary to produce a desired rate of ascent, and how much gas he must vent in order to descend. Above all, there was the question of stability. He must adjust the length of the cables attaching his capsule to the huge, pear-shaped balloon, to damp out vibrations and get the smoothest possible ride. Thus far, he was lucky; at this level, the wind was steady, and the Doppler reading on the invisible surface gave him a ground speed of two hundred and seventeen and a half miles an hour. For Jupiter, that was modest, winds of up to a thousand had been observed.

But mere speed was, of course, unimportant, the real danger was turbulence. If he ran into that, only skill and experience and swift reaction could save him, and these were not matters that could yet be programmed into a computer.

Not until he was satisfied that he had got the feel of his strange craft did Falcon pay any attention to Mission Control’s pleadings. Then he deployed the booms carrying the instrumentation and the atmospheric samplers. The capsule now resembled a rather untidy Christmas tree, but still rode smoothly down the Jovian winds while it radioed its torrents of information to the recorders on the ship miles above. And now, at last, he could look around…

His first impression was unexpected, and even a little disappointing. As far as the scale of things was concerned, he might have been ballooning over an ordinary cboudscape on Earth. The horizon seemed at a normal distance; there was no feeling at all that he was on a world eleven times the diameter of his own. Then he looked at the infrared radar, sounding the layers of atmosphere beneath him and knew how badly his eyes had been deceived.

That layer of clouds apparently about three miles away was really more than thirty-seven miles below. And the horizon, whose distance he would have guessed at about one hundred and twenty-five, was actually eighteen hundred miles from the ship.

The crystalline clarity of the hydrogen-helium atmosphere and the enormous curvature of the planet had fooled him completely. It was even harder to judge distances here than on the Moon, everything he saw must be multiplied by at least ten.

It was a simple matter, and he should have been prepared for it. Yet somehow, it disturbed him profoundly. He did not feel that Jupiter was huge, but that he had shrunk to a tenth of his normal size. Perhaps, with time, he would grow accustomed to the inhuman scale of this world, yet as he stared toward that unbelievably distant horizon, he felt as if a wind colder than the atmosphere around him was blowing through his soul. Despite all his arguments, this might never be a place for man. He could well be both the first and the last to descend through the clouds of Jupiter.

The sky above was almost black, except for a few wisps of ammonia cirrus perhaps twelve miles overhead. It was cold up there, on the fringes of space but both pressure and temperature increased rapidly with depth. At the level where Kon-Tiki was drifting now, it was fifty below zero, and the pressure was five atmospheres. Sixty-five miles farther down, it would be as warm as equatorial Earth, and the pressure about the same as at the bottom of one of the shallower seas. Ideal conditions for life. A quarter of the brief Jovian day had already gone, the sun was halfway up the sky, but the light on the unbroken cloudscape below had a curious mellow quality. That extra three hundred million miles had robbed the Sun of all its power. Though the sky was clear, Falcon found himself continually thinking that it was a heavily overcast day. When night fell, the onset of darkness would be swift indeed; though it was still morning, there was a sense of autumnal twilight in the air. But autumn, of course, was something that never came to Jupiter. There were no seasons here.

Kon-Tiki had come down in the exact centre of the equatorial zone the least colourful part of the planet. The sea of clouds that stretched out to the horizon was tinted a pale salmon, there were none of the yellows and pinks and even reds that banded Jupiter at higher altitudes. The Great Red Spot, itself the most spectacular of all of the planet’s features, lay thousands of miles to the south. It had been a temptation to descend there, but the south topical disturbance was unsually active, with currents reaching over nine undred miles an hour. It would have been asking for trouble to head into at maelstrom of unknown forces. The Great Red Spot and its mysteries would have to wait for future expeditions.

The Sun, moving across the sky twice as swiftly as it did on Earth, was now nearing the zenith and had become eclipsed by the great silver canopy of the balloon. Kon-Tiki was still drifting swiftly and smoothly westward at a steady two hundred and seventeen and a half, but only the radar gave any indication of this. Was it always as calm here? Falcon asked himself.

The scientists who had talked learnedly of the Jovian doldrums, and had predicted that the equator would be the quietest place, seemed to know that they were talking about, after all. He had been profoundly sceptical of such forecasts, and had agreed with one unusually modest researcher who had told him bluntly: “There are no experts on Jupiter.” Well, there would be at least one by the end of this day.