The disperser took three full working days to get to the point where we were ready to begin. Naturally the People’s Space Exploration Foundation, back home, hadn’t seen fit to provide us with a hatch that a complete disperser could go through, or a disperser that could go completed, through our hatches, so we had to check out components, get the three pieces ready to go together, and then plan to assemble them outside in space. All this, of course, without complaining, since you never knew what Streeyeptin might remember once we returned.
When at last we were sure that all three pieces were working well and could be interfaced to the others, just five days out from Setepos, the captain turned on the antiproton spray and turned off the zero-point energy lasers that had propelled the ship all the way here from Nisu and were now braking us as we came into the Setepos System. Abruptly, the acceleration was zero, and we were weightless.
The three assistants met with the captain just before we went outside to put the disperser into place. Our being chosen for this part of the mission meant we were “about to set the record for the fastest spacewalk in history,” Captain Baegess pointed out. “We think our system for protecting you will work, but of course this is the time we really find out. At least so far, for the last tenth of a day, nothing big enough to hurt you has hit the ship.”
“Except the gamma radiation,” Krurix pointed out, voicing what Bepemm and I had been thinking.
“Except the gamma radiation,” Captain Baegess agreed, “but that’s not nearly the problem that being blown apart would be.”
Though we were now far below light speed, the velocity of our ship was still so high—about ten thousand times that of a slug coming out of a modern steam rifle—that a dust grain delivered more than enough energy to tear one of us in half, and as we were now entering the new solar system, dust was getting thicker outside the ship.
Inside the ship we had been protected by our deceleration exhaust; any dust that drifted into the zero-point energy laser was either vaporized (if dark), or accelerated away from us at great speed (if reflective). The particles streaming away helped to clear space in front of us as well.
But we couldn’t work outside with the laser turned on, and so it would not protect us from the dust we would be running into. Instead, the captain had flipped the ship back over so that its nose pointed in the direction we were going again. We would use the antiproton spray that had protected the ship during the long years of acceleration.
The antiproton spray was simply a long tube running through a magnetic coil, pointing out into space ahead of us. There was a big negative charge on the ship end of the tube, and a big positive charge on the far end.
Because antiprotons have a negative charge, a fine mist of antiprotons sprayed into the tube would accelerate away from the negatively charged ship, follow the lines of the magnetic field down the tube toward the positive charge that attracted them, and shoot out into space at close to light speed. When one of them struck a dust speck, a small part of the burst of energy released by the antimatter/matter reaction would be transferred to the speck (like a bomb going off next to a rock) and the speck would shoot off away from us (since the “explosion side” would always be toward us).
The problem was that while a small part of the energy would move the dust speck, a large part of that energy would become hard gamma rays; those of us outside were going to be exposed to some radiation over and above the usual space crew’s dosage, even with the whole ship between us and the antiproton spray. “That’s why we want you to work fast,” Captain Baegess reminded us for the hundredth time. “Your suits provide some protection, but not nearly as much as being inside the hull of the ship. So get done quickly; we don’t want to have to treat anyone for cancer on the way back, and we want everyone to come back.”
“Yes, sir,” I said, along with Astrogator’s Assistant Bepemm.
Engineer’s Assistant Krurix added, “We feel just the same way.”
The captain had a chronic problem with Krurix, who couldn’t seem to respond to simple orders without making a joke out of them, and Bepemm rolled her eyes at me as if to say, Here we go again, punished for whatever Krurix does, but either the captain was in a good mood or saw the humor in the situation, and said, “Then we’re all in agreement. Good, then. Go get it done.”
The dispersion coil was simply a big set of superconducting electromagnets forming a lumpy torus; each of us would go outside with one-third of the torus. We would connect the parts together and mount them around the aperture of the laser—all the while taking a certain amount of hard gamma from antiproton reactions that took place far enough out to the sides so that the ship did not shield us from them.
Krurix was occasionally annoying, but he was good in weightlessness and he was quick about his work; Bepemm and I were glad to have him. We got the assembly done in less than the expected time, and then mounted the disperser. A quick run through the checklist showed it was working properly.
“Thetakisus, look at the sky, up toward the ship,” Krurix said suddenly, his voice crackling in my helmet radio.
I looked up. For an instant I saw only stars, among which Kousapex, just by the ship, was now much the brightest. There were some brief flickers—then as I realized what I was looking for, I saw the dozens of little dancing streaks of light seeming to form a crown around the nose of the ship.
Bepemm’s voice said, “Must be a side effect of dust hitting the antiproton spray. Probably the antimatter reaction heats the dust motes hot enough to glow.”
I watched for another instant and said, “I think you’re right. The streaks are blue-white at one end and red-orange at the other.” Now that my eyes were adjusting, I realized that there were hundreds of streaks. “The bright ones must be the closest, and the dim ones must be the farther-away ones. And when you look at them all as a group, you can see that the blue-white ends are toward the center and the red toward the outside. Just what you’d expect.”
“I think it’s just beautiful,” Krurix said softly.
“You’re right,” Bepemm said, “and I’m glad we saw it . . . but every streak started from an event that put out a lot of hard radiation. And there are a lot of those events, and we can see the blue ends of quite a few—and if we can see them, they can irradiate us. Not to mention that probably only the dust collisions are showing visibly—there must be millions of collisions with stray atoms for every visible dust streak—and all those are making hard gamma, too. It’s beautiful, but I think we’d better go inside.”
“Yeah,” Krurix said, some disappointment in his voice.
For the first time on the voyage, I felt a little sympathy for him. It was beautiful, now that I could see it clearly, like a flower with thousands of hair-fine petals, a blue-white center with red edges. We went in, verified that all the tools had come in with us, and closed the outer airlock door. There was a push against our suits as pressure came back, and then the inner door slid open. Before we were quite out of our suits, there was a strange lurch as the ship flipped, and then the captain put the ship back under deceleration. By the time we made our way to the cockpit for our report, he had already tested the disperser and found it to be working perfectly.
When we were just one day away from Setepos, we were all terribly seasick. An ordinary orbital transfer maneuver is pretty smooth, but we weren’t going into orbit around Setepos—we were joining its orbit around Kousapex, so close that Setepos’s gravity perturbed our motion severely. Thus our interaction with Setepos (and its moon’s) gravity was not the smooth, gradual change of accelerations with which the ship cooperated (so that we were in free fall and didn’t experience it at all). We were coming in under acceleration of our own, hopping back and forth so that our laser exhaust did not intersect surfaces where it might cause explosions. Thus our acceleration varied rapidly and unpredictably from zero to almost a full gravity, shaking us all like a sailboat in heavy chop.
When it finally stopped it was absolutely abrupt; one moment
we were still pitching about as Egalitarian Republic swung from side to side, thrusting and turning off, thrusting and turning off—and the next moment it felt as if we were already sitting on the planet’s surface. I looked up from where I had had my head down in a sickness bag and saw that one viewscreen showed the broad face of Setepos spread out below us. Bepemm and I hastened to wipe our faces, and then hurried up the ladder to the main viewing room. This final approach was to be conducted by the captain, his first officer, and the engineer and engineer’s mate, and thus there was nothing for us to do. Krurix had elected to observe from the engine room, so we would not be troubled by his irritating presence either.
The only other person in the main viewing room was Political Officer Streeyeptin; he seemed friendly enough today, and besides there was hardly anything controversial we could have said about it. He motioned us, graciously enough, into seats near his, by the big screens.
It was hard to believe a world could have so much land. We were looking down at one of the most land-rich possible views, hovering over the area where Big and the Hook, the two largest continents, joined.
Streeyeptin gestured at one screen. “You can see you did good work with the disperser.”
We had wanted to be as near as possible to the site where the Gurix had set down (always assuming our fragmentary record was accurate), near the mysterious village, since this would allow us to use line-of-sight radio to operate one of the rovers directly from the ship and take a good, thorough look around before sending our own landers down. Fortunately, directly to the east of that area there was a sizable sea, with more than deep enough water to let us point our zero-point energy laser into it. Now we could already see the great billow of white clouds, brilliantly illuminated even in daylight by the powerful laser. Slowly a plume of dense clouds was drifting out of the focus of the beam, eastward toward land.
“There are going to be some big rains down there in a few days,” I said.
Streeyeptin nodded. “We can only hope that we aren’t setting up flash floods upstream of any Nisuan colonists. We’re certainly going to fill up some lakes, put some extra snow on mountaintops, and make the rivers run faster while we’re here.”
When the zero-point energy laser had first been pointed at that area— the size of a large city back home—water had boiled down to a depth of just over sixty bodylengths, but now the dense clouds were dispersing most of the heat before it reached the surface of the water. The sea surface was still boiling, but most of the heat was carried off by the great plume of steam that reached high into the atmosphere, constantly heated by the laser light pouring down on it from above.
“The Creator alone knows what we must be doing to their weather,” Bepemm said; she winced at referring to the Old Religion in front of the Political Officer.
If he noticed, he gave no sign. “I wonder if that’s visible in the daytime from the colony site—it surely must be at night,” he said. “Well, whoever— or whatever—is down there, I suppose they know something is happening, even if they don’t know what.”
“Assistant Thetakisus, please report to the cockpit,” Captain Baegess said over the communicator. “We want to get a rover operational as soon as we can.”
“Yes, sir,” I responded, and hurried to comply.
When I got there I found an argument in process. Naturally half of the argument was Krurix, but the surprise was that he was arguing with Chief Engineer Azir, and in front of the captain besides. Usually Krurix worshiped Azir, the one officer he obeyed without mouthing off.
I slipped unnoticed into the cockpit—it seated eight when it had to, and there were only five of us present, so I simply took a seat by a utility console and waited.
“—just a day or so,” Krurix said. He sounded like he was trying to keep his voice even. He wasn’t managing it, quite. “If we just put the ship into orbit—it’s a simple maneuver—and spend a day in free fall, we can do the overhaul. It won’t be too much trouble. Not compared with getting shipwrecked.”
“You’re willing to go to all that trouble because you don’t like the responsiveness graph, although it’s well within tolerance?” Azir asked. Her tone was gentle, but it was clear that she was incredulous.
First Officer Beremahm was obviously enjoying the argument and wasn’t about to say anything; her quiet gesture to me indicated that as usual she thought Krurix was ridiculous and was going to enjoy watching him make a fool of himself. As always, that gave me mixed feelings. As senior assistant on board, I felt that whatever the other two assistants did reflected on all of us, and Krurix, with his constant arguing and chasing off after any stray idea at all, embarrassed me terribly. Yet at the same time, Krurix was one of us, and if he thought (for whatever unfounded reason) that the ship was in danger of crashing, I wanted his views taken seriously.
So I sat there wondering what I should say, if anything.
Fortunately, Captain Baegess wasn’t one to take chances, even if he didn’t think much of Krurix either, so he saved me the trouble of thinking about how to draw him out. “Tell us about it, Krurix, please. Why you think it’s something to worry about, I mean.”
“Well,” he said, “it’s kind of basic. Zero-point energy gets produced when charged plates that are only about twenty atomic radii apart are pushed down to within a few atomic radii of each other. The space is lasable, so all that energy ends up as laser light and drives the ship.”
“Thank you for your tour of the ship, sir, it has been very educational,” Beremahm said, so sarcastically that Krurix cringed.
But Azir came to his defense. “I think Krurix was just laying out the basis for his physical reasoning,” she said. “He’ll get there soon enough.”
Krurix gulped and went on. “Well, to get continuous power we have to vibrate those plates really fast. The faster we vibrate them, the closer they get together at the bottom and the more times the laser pulses per unit time. So to increase thrust we cycle the plates faster. Well, this time, as we were executing maneuvers, I was running all the routine checks, and I was surprised to see that when we changed the speed of vibration, the profile of change wasn’t what it should be. It was like the plates kept vibrating at the old speed a little too long, and then abruptly jumped or fell to the new speed, with just an instant or two of chaos in between. May I show you on the screen?”
“Please do,” Captain Baegess said.
Krurix turned to his console and clicked a few times; two graphs sprang up on the group screen. “You see?” he said. “The smooth one on the left, that looks like an ordinary exponential decay, is the way it’s always looked before today. The one that looks like a jagged step function, with that little ‘twang’ of noise just before it levels off, is what it’s been doing today.”
First Officer Beremahm stopped smiling and sat much farther forward. “What do you think is causing it?”
“Well, this is where I’m just going by analogy. The vibration of the plates is approximated by a simple harmonic oscillator, right, like a pendulum, a water wave, or a weight bouncing on a spring. And what changes the behavior of other simple harmonic oscillators is changes in damping—how sticky the pivot on the pendulum is, how thick the stuff the pendulum moves through, how viscous the water is, how flexible the spring is and how much kinetic energy it returns per potential energy put in. So my guess is, something has changed in the plates, or more likely in the superconducting magnetic levitation we use to keep them in place. And if it’s starting to change—after being completely stable for literally years at very high acceleration—since we don’t have any lab experience with an engine like this running for this long under such high accelerations, I don’t think we can dismiss the possibility that the plates might fall together, or spring apart, and stop vibrating. And if that locks up . . .”
“Oh, but then we’re fine,” Azir said. She was obviously relieved. “We have an emergency backup system to reseparate the plates and start them vibrating again. It might be a long, frightening fe
w moments while we fell, but we’d be fine, once the engine cut back in.”
Krurix sighed. “Well, yeah, but then I started to play with the computer simulation. The emergency separator takes some time to cut in. And that time is long enough for us to fall into the outer atmosphere of Setepos. Once we do, we’ll need to accelerate a little above one gravity to keep from hitting the surface—but if we turn the engine on with that much power” —he clicked on his console again—”here’s what happened when we first put about that same amount of power into the atmosphere— infrared picture.”
Before our eyes, we saw a great plume of superheated air leap upward, far above the surface. Captain Baegess made a noise of acknowledgment. “How big is that explosion?”
“Like a good-sized hydrogen-fusion device,” Krurix said. “And it doesn’t care how close we are to it. Way up here, far above it, it’s just interesting to watch. But if we were down there in the atmosphere, it would happen right next to us. Temperatures, pressures, and accelerations far above what the ship was ever designed for.”
“It would blow us apart,” the First Officer said, her long Shulathian ears pulling back as she thought about it. “I see what you mean, Krurix, and yes, you were right to bring it to our attention.”
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