Chapter 4 — FLIGHT INTO VACUUM
I have only an inkling of what my father did to organize for our horrendous trek across the surface of Callisto. (I have not run a dateline for this entry because it follows the last without change of locale. A foolish consistency, as Señor Emerson said many centuries ago, is the hobgoblin of little minds.) Probably he did not want us to know, for it could hardly have been completely legal. Officially, we were preparing to vacate the premises; actually, we meant to vacate the planet.
All of our private holdings were liquidated on the gray market and the money used to buy third-hand surface suits for each of us, together with compact food packs and water filters. There was enough left over to cover the down payment on a junky low-gravity transporter.
That was all. We could not keep our toys and dolls and treasured books. Surface suits had very little room for extra things, even if we hadn't needed the pittances the sale of those things brought. Spirit tried hard to conceal her tears, no longer quite so thrilled about the journey, and I went bleakly about the business of cashing in. We knew what was at stake.
I kept the laser pistol, however, squeezing it into an exterior pocket, and I knew Spirit kept her finger-whip.
As far as I know, no final payment was made on the mortgage. It was not that we sought to cheat Colonel Guillaume, who had done the best he could for us within the limits of his philosophy, but that the foreclosure already represented a fair profit for him, since we had built up a fair equity over the years which he would not have to transfer to the coffee-plantation residence. Perhaps he knew what we intended and did not report us to the authorities for that reason. As long as his hands were technically clean and he made a fair profit, he did not mind our effort to seek a better life elsewhere. Certainly he could have stopped us, had he wished to.
We left at night, in order to avoid any police watch. Again, it would not have been possible to escape the dome of Maraud if the authorities had really cared to prevent us. But we were only peasants; they were hardly concerned if we took it upon ourselves to depart the good life we supposedly had here.
I should explain that leaving a dome is no simple matter. Callisto is an airless world, terraformed only in particular spots. It is the same with all the moons of Jupiter, and indeed throughout the Solar System other than Earth. The domes are made of huge bubbles grown in the massive atmosphere of Jupiter, floated to the local surface by means of standard antigravity shields, cut in half, and cemented to surface plates. The fit had to be strong and tight, or the pressure of the air inside would blow the dome apart and right off Callisto. So entrance and egress were only by air locks, and these were not carelessly supervised. The city-dome of Maraud is 1.3 kilometers in diameter, so that each of its 100,000 (approximately) inhabitants can have a floor space of at least ten square meters. Of course family units like ours increased their effective floor space by living in two-story homes. Anyway, there were only two locks big enough for vehicles, and only one of these functioned at night, so that part of our course was set.
Mother and the girls bundled down in the cargo cage, while I got to sit up front with my father. I know this is teen-age foolishness, but it made me feel important, and I felt as if I were a real adventurer in the control cabin of a sleek Jupiter Navy spaceship, copiloting through the starry galaxy. Of course Navy ships do not cruise the galaxy; the relativistic limitation confines mankind largely to his own Solar System. Still, this was the way my imagination went. Imagination allows more leeway than does reality, which is perhaps why we come equipped with it. What a horror it would be to be forever restricted to reality!
"Special order of garbage," my father called out to the technician in charge of the lock. That damped my fantasy somewhat; garbage is not exactly the stuff of high adventure. Still, this too was a kind of fantasy. At least I prefer that description to the alternative of calling my father a liar.
My father proffered a folded paper. The technician took the paper and glanced at it. It was a standard twenty-dollar bill, an obvious bribe. "The authorization seems to be in order," the man agreed, pocketing it. "Get that garbage well away from here." He pressed the buttons and the air-lock panel slid clear.
The "garbage" of course was my mother and two sisters, hunched in the cage with our limited supplies. I wondered whether they appreciated the humor.
My father drove on. It was a pedal car, of course, as few motors operated conveniently in a vacuum and very little power was needed on the airless, low-gravity surface. Inside the dome the pollution of ordinary motors was unacceptable and distances were short, so the pedalers made sense there too. It occurred to me that the dome of Maraud was very like an ancient walled city, small and crowded but secure from the enemies without. In this case the enemies were vacuum and low gravity and terrible cold. This was also one reason that projectile weapons were not used inside the dome; the substance of the dome could reflect a laser beam fairly harmlessly, but a powerful enough projectile just might make a hole, and such a nightmare was not to be risked.
We secured our suits, which hung on us awkwardly, made sure the three in back were secure, and sealed our helmets. The lock panel slid closed behind us, the warning klaxon sounded, and the air pressure dropped. I had been outside the dome before, of course, on field trips in school, so I knew what to expect. But this time it was excitingly real, for we planned never to return. There was no hospital tank along to rescue us if we suffered a suit blowout, and no home for us to relax in if we turned back. They might not even open the lock for us. We were committed with an uncompromising finality that awed me in a somewhat squeamish manner.
Faith sat up suddenly in the cage, pointing to her left leg. That leg was not very shapely in the suit, but that was not the point. A thin plume of vapor jetted from a pinhole there. Hastily my mother slapped a seal patch on it, pressing it tightly in place. These were old, battered suits, which was why we had been able to afford them. Some problems were to be expected—but this served to remind me, as if I needed reminder, that the danger was real and immediate. If any of us suffered a full-scale blowout, that person would be lost.
Our suits inflated and grew taut as the last of the air went, without any other problem. Fortunately there is not much actual force behind a pinhole leak, and an external patch can readily contain it. I gave a silent sigh of relief.
The outer panel on the lock slide open and we pedaled out onto the barren surface of Callisto. We were truly on our way!
The distaff contingent of our spaceship (as I fancied it) sat up and more or less joined us once we were clear of the lock. We could not readily talk with each other, for these primitive suits lacked radios, and of course there was no atmosphere to conduct our sound. But there was sound; it was conducted through the vehicle and our suits. We heard, as it were, through the seats of our pants. It wasn't very clear, since there was also the rattling of the pedal car, but it was better than silence.
Spirit leaned forward over the top of the cage and touched her helmet to mine. "Isn't this fun?" she cried, so loud that I jerked my head away. Head-to-head conduction was much more efficient! "Valhalla, here we come!" That last was through the seat, much dimmer.
Valhalla is the monstrous system of concentric rings associated with a huge old crater, extending out about fifteen hundred kilometers from its center—a significant fraction of the planet's surface. Maraud is about one hundred kilometers outside that formation, and the bootleg bubble was hidden in an old crater hangar about two hundred kilometers within it, so we had a good three hundred kilometers to go. We could travel up to forty or fifty kilos per hour in this trace gravity, however, so that was all right.
The city domes, you see, use gravity lenses to concentrate gravity inside them, bringing it up to Earth norm, what we simply call gee. This is actually another aspect of the gravity shielding used to make saucers float above ground and bubbles float between planets. There is no such thing as blocking out gravity, but it can be diluted or intensified in limited regions by the lenslike shields, somewhat the way light itself can be affected by a properly curved lens. That's a considerable oversimplification; the actual science of gravity manipulation is far too complex for an amateur like me to comprehend. But I am sure that gravity variation is the key to the human colonization of the Solar System, because it makes both travel and residence feasible anywhere in space. Not easy, understand, but feasible, because of the enormous savings in energy required for these activities.
My mind reviewed what I had learned in school, for it was suddenly more relevant to my immediate existence. The human species had originated on the Planet Earth, but population had expanded voluminously until there really wasn't room for everyone. For reasons that weren't entirely clear to me, this caused people to react violently, and they were afraid there would be a bad nuclear war that would destroy everything. But then the discovery of gravity shielding, popularly and not too accurately called antigravity or null-gee, had enabled the extra people to emigrate to the other planets and moons of the Solar System, and the threat of internecine war had faded for a while.
For a while—that is a significant qualification. According to my history texts, the crush of overpopulation on Earth and diminution of resources had been set back by some five or six hundred years. As it happens, those years have passed, and we are now back to the point, population/resource-wise, where we were just before the discovery of the technique of gravity manipulation. So we face the problem again—only this time grav-shielding isn't enough to abate it. That makes me nervous, when I think about it.
The early colonization of the Solar System proceeded rapidly, for the shields enabled man to hoist huge masses into space. The problem of air and food and water remained, however, so there were limits. It was like man's discovery of the lever: It enabled him to multiply his force, but not indefinitely. One enterprising company had fitted a gravity lens to an ocean liner and sailed it through the air. But it was clumsy outside its natural element, subject to errant winds, and when it sailed too high, the passengers suffered from the thinning of the air. Airplanes had similar problems, actually, as they flew beyond the normal atmosphere. Efficient as an airplane may be in air, it becomes clumsy in vacuum, for its wings cannot plane through nothing. So in the end the compact, simple, tough bubble became king of space. From the outside a bubble most resembled a planetoid with portholes, or a little round meteor with craterlets on it, but inside it was a temporary world.
Bubbles floated out to all the other planets and moons and fragments, carrying gravity lenses and construction equipment that could operate in a vacuum. Bases were established throughout the Solar System in the course of the first century following the null-gee discovery. New nations sprang up in the likeness of old, as individual Earthly governments operated competitively to establish their domains in space. The American continents of Earth centered on the richest prize, the gross planet Jupiter and its moons, while the Asians settled for the next-greatest prize, beautiful Saturn, with its rings and many small moons. The smaller or more distant planets, considered less desirable, were left to the lesser powers of that day: the Africans, who got the hot inner worlds of Venus and Mercury; the Europeans, who got Uranus; the Moslem states, who got Neptune and its oil-rich satellite Triton, and the remainder somewhat haphazardly distributed among other special interests. A number of the other powers claimed shares of frigid Pluto and its satellite Charon, hoping eventually to discover and exploit rich resources there. There was no established population on Charon or Pluto, however; they were just too far out, and the sunlight there was too dim to be usable for power.
This was part of the education I had suffered in school, which I now parrot back as if it represented original thinking on my part. Would it were so! I happen to have a flair for geography, so I did well, but most of my fellow students professed to find it boring. I could make fairly precise matchings of each planet or moon with an equivalent political entity of six hundred years before on Earth; no one else saw any point in such a game, and I can't honestly claim it is more than idle entertainment.
Oops—did I write that the Moslems of Earth took Neptune? I would have flunked that question on an exam! Already my school learning fades and becomes confused. It was Mars the Moslems took; Neptune was—let me think now—that went to the Australians. Yes, now I have it straight!
I experienced queasiness that interrupted my chain of thought described above. I tend to think too much, as I may have confessed before. "Say, fun!" Spirit exclaimed brightly against my helmet. "We're passing out of the lens!"
True enough. The lens concentrated gravity in Maraud to Earth normal, but outside the dome gravity thinned out, since this was the depressed area three or four times as broad as the dome. Gravity doesn't come from nothing, after all. Now we were coming into the true natural surface attraction of Callisto, which was a little more than a quarter Earth norm. From one gee to one-tenth gee to one-quarter gee—it was vaguely like riding ocean waves. I have not had direct experience with any large body of water, but can imagine it. Maybe we were riding gravity waves.
The outer surface of Callisto is bleak, barren, and frankly, dull. Our world is the most heavily cratered significant body in the Solar System, for the past billion years of new meteoric strikes have only replaced old craters with new ones, not changing the total number. One might suppose this would make for a singularly variegated terrain, but that is not so. Right here on the surface it simply wasn't that interesting. On other planets there may be deep oceans and high, jagged peaks; not so Callisto and our sister planet Ganymede. These are two iceball worlds, of low overall density because of the ice, and, though the surface is crusted with rock and dust, the thick mantle of ice below prevents any really spectacular mountains from forming.
I'm not sure I'm getting this across. You see, ice is as hard and stable as any other rock at the local temperature of 100 degrees Kelvin—I'm not as good at figures as geography, but that's an easy one to remember, one hundred degrees Celsius above absolute zero—but at the local noon (which of course has no relation to the Earth time we use inside the domes), it can be fifty degrees warmer, and deep down below the pressure can heat it some too, so in the course of millions of years that ice does soften and flow a little. This planet has been around for four billion years or so, so the flow obliterates the extreme features. Result: shallow, rounded craters standing, as it were, shoulder to shoulder, rim to rim, and one inside another, and overlapping: This world is made of craters, and none of them are any effort to navigate. There are no cutting edges on Callisto. You might say the features of the surface have been eroded by water: not water coursing over from above, as on Earth, but slowly squeezing out from below. That's why we were moving along so well in our wheeled vehicle; there was very little natural obstruction.
The sky was more interesting. This was night, on the surface as well as inside the dome, but Jupiter was full, and his baleful light flooded the rolling rills of Valhalla. Jupiter was anything but dull, with his violently contrasting bands of atmosphere and the various gaseous eyes staring at us. Surely Jove was watching our puny efforts with disdain—but he was our destination. I was, of course, sorry to leave my home world, for all my experience was invested here on Callisto and all my prior hopes for success had been defined by the Halfcal culture and hierarchy. But I knew that in those bands of turbulent color on the Jovian Planet was opportunity as vast as Jupiter himself. We would certainly be better off there; we would no longer be peasants, there!
I looked directly up, trying to see the other gravity lens, the one above us, close. Such lenses don't just fix the gravity inside the domes, they govern the light we receive. This can be hard for people who don't reside on moons to understand, so I'll try to make it simple: Light is affected by gravity, technically the curvature of space that we call gravity, so a lens that bends gravity waves also bends light waves. Properly formed, a large gravity lens can be used to focus the light of the distant sun on a smaller area, making it proportionally more intense. There's a lot of energy in light, as a magnifying glass can demonstrate when used to set fire to things. Since the sun's light is much less intense out here at Jupiter's orbit than it is at Earth's orbit, we need to focus it to match what our bodies and our plants are used to. We are all transplants from Earth, really, though we may have been born or seeded here; a few centuries can't erase a few billion years of evolution.
So above each dome-city is a huge gravity lens that is twenty-seven times the area of the dome, and the lens focuses the wan sunlight to that amount, and it shines in through the dome's transparent roof to light and warm the city, exactly as would be the case on Earth. Well, not exactly; Earth's copious atmosphere filters out many deleterious aspects of the radiation, so our twenty-seven-times-concentrated sunlight would burn us if we took it straight. But the material of the dome is designed to filter out the harmful radiation, substituting for the missing depth of atmosphere, and so the net effect is similar.
The same is true for the agricultural domes; they are literally greenhouses. This is convenient to do on an airless planet, since nobody lives outside to complain about being deprived of sunlight. Naturally the focused brilliance at the dome is at the expense of the twenty-seven-times-as-large area around it, which receives very little light. We had not noticed any difference because we pedaled through this zone at night. But it would have been night by day also, near the dome, if you see what I mean.
It's really more complicated than that, because Callisto's day is the same as its period of revolution around Jupiter: sixteen and two-thirds Earth days. One face—Halfcal's—always faces Jupiter; the other always faces space. So we have eight and a third days of continuous light, and then a night just as long. We humans don't like that; it doesn't match our biological rhythm. So we exchange light with a sister city around the globe: San Pedro, in the Dominant Republic. San Pedro is always in darkness when Maraud has light, and vice versa, so there's always sunlight one place or the other. We never have clouds or bad weather, of course, the way Earth does; in fact, we have no weather at all. When Maraud is in sun, we use it for twelve hours, then refract it around the planet, in the form of a concentrated light beam, using a chain of vertical gravity lenses, to San Pedro.
In this manner we have our night in the middle of the Callistian day, while they have their day in the middle of their night. When they are light, they send us twelve-hour segments of daylight. This is the most fundamental and absolute system of cooperation between the two nations of our planet, and is inviolate. If Halfcal and the Dominant Republic went to war with each other—and sometimes, historically, it has come to that, for we are a bickering culture—neither would abrogate the light exchange. Without it, life as we know it would be virtually impossible on Callisto. We depend on the sun for almost all our energy, for we have no great deposits of oil or uranium and lack the technical and industrial base to establish a hydrogen-fusion power plant.
But my glancing was wasted, for the huge elevated gravity lens was not visible. Not only did it operate only in daylight, it was not physical at all. It was generated in space, forming between key points. There was nothing to see. Still, my eye sought it out, much as it sought the gaze of a person in a picture looking in another direction. This foolishness is inherent in my nature; I seek constantly to relate to people and things directly, even when I suspect it is unwise or impossible.
My attention wandered to the other large moons of Jupiter, all closer in than ours. Ganymede, off to the side of the Colossus, its brightness at three-quarter face; it was almost halfway in toward Jupiter, from our vantage. That is, its orbit is just over one million kilometers out, while Callisto's is just under two million. We would pass that inner orbit on our way to Jupiter, but would not pass close to Ganymede itself, because it revolved about the planet more than twice as fast as we did and would rush to the far side when our bubble passed, as if avoiding us. Just as well; the recent political revolution there seemed to have made things even worse for peasants than before. As the ancient poet Coleridge put it: "They burst their manacles and wear the name / Of Freedom, graven on a heavier chain!" But of course Europa was little better, while the innermost big moon, Io, zooming all the way around Jupiter in less than two Earth days, was hardly habitable, even with terraform domes. No, no hope for us on the other moons.
Down near the horizon behind us I spied a speck of light I didn't recognize. It wasn't a star, for it was moving, shifting somewhat erratically above the landscape, as if guided by some human hand.
"Saucer!" I exclaimed. "What's it doing out here at night?" For there was very little interdome travel by night, as Callisto is essentially a hinterworld with no major industry, other than agriculture. Unlike the hyperactive denizens of major worlds, we preferred to sleep at night.
"The Maraud authorities wouldn't chase us, would they?" Spirit asked. My parents were consulting with each other, helmet to helmet, but I couldn't hear their dialogue, to my annoyance.
"Shouldn't," I agreed tersely. "We're not breaking any law. We're just leaving the city, as ordered."
"And the planet," she added. "If they found out about that—and they might suspect, the way we snuck out."
"Maybe," I agreed uneasily. I would have disparaged the notion out of hand—since I knew the Maraud authorities did not care about us—except for the fact of the saucer. There had to be some reason for it to be out here, and we could not safely assume that reason had nothing to do with us.
The light zoomed toward us. In moments we recognized a private pick-up craft, used by explorers to collect samples of minerals from the planet's surface. Callisto was extremely shy of heavy minerals, which made them all the more valuable. Prospectors were constantly ranging out with metal detectors to search for what few nuggets there were. A lode of iron ore could make a man's fortune. Even mineral dust was far more valuable on Callisto than it was elsewhere, except on Ganymede. Most of our metals had to be imported from the inner planets of the Solar System, and even with the gravity shields, that was expensive.
This craft was typical. It had a nether power scoop and a fair-sized storage compartment and a sealed cockpit with windows looking forward, upward, and down. That meant the occupant did not have to suffer the inconvenience of wearing a space suit, the way we peasants did. Cheaper saucers were not sealed; they might be hardly more than flying platforms, and a miscue could dump the operator off. Not so this one. I envied whoever could afford this sort of vehicle: sealed afloat instead of suited and landbound like us.
The saucer came right up to us, evidently using a metal detector to spy us out. The metal was the main value in a pedal car; it could be melted down and lose only a fraction of its price, and it would be very easy to spy from the dome. However, there was not a great deal of metal here, for most of the transporter's mass was plastic; for a saucer to come out in the hope of salvaging a vehicle like this—no, that didn't make much sense.
It all came back to the original question: why would anyone be looking for us? Legal or illegal—I think our status was now hazy—we remained only refugees, nothing people, completely unimportant to anyone except ourselves.
The saucer paused to hover directly over us, putting us in shadow. That hardly mattered; we weren't trying to draw on Jupiter's pale radiance for power. Then a bright beam of light speared down at us from a unit by the cockpit, blinding to our Jovelight-acclimatized eyes. It found us and blinked off and on again, rapidly, several times.
The saucer was signaling us. It was, of course, impossible to communicate by sound through the vacuum when there was no direct physical contact. Saucers used radios to talk to each other and the city domes, but of course we didn't have a radio. We didn't have a flashlight either, and in any event didn't know the blinking communication code. We didn't have anything that wasn't essential to our progress across the surface or our journey through space, because everything cost precious money. We were unable to make any meaningful response. So my father just waved and pedaled on.
The nether hatch in the saucer opened. The scoop pincers descended slightly, holding something. They were going to drop us a message!
The pincers descended, in order to get below the grav-lens. It was possible for objects to pass right through it without interfering with its function; gravity does not obey ordinary rules. Once below, the pincers cranked open to release the message capsule. It was a bright-orange cylinder that seemed almost to glow, even in the shadow.
Suddenly our transporter swerved violently to the left. I was jammed into the right wall of the vehicle. We must have hit a craterlet. Craters aren't all landscape-sized; they graduate on down to pinhead size, and some of those can be almost as deep as they are broad. They have less mass to flatten them out—no, I'm wrong, how can a hole have mass?—or maybe it is that they are fresher, so have not yet melted down to gentleness. Geologically speaking, any crater less than a million years old is an infant, born yesterday. Yet my father surely would have seen it and avoided it. Anyway, it was a bad jolt. Spirit, perched high, had to grab my head to keep from being flung out of the vehicle.
I must recreate what followed partly from logic, as my entanglement with Spirit prevented me from paying full attention. The message capsule missed us and struck the rock to our right. It exploded on contact, gouging out a new little crater. That one really was fresh! The impact of the flying debris bounced off our vehicle and the expanding gas shoved the transporter across the sand. We were very lucky no sand holed our suits.
That capsule was no message—at least, not the kind we had anticipated. That was a bomb!