Encounter With Tiber

by Buzz Aldrin

  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 she didn’t think much of Krurix either, so she 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 few 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.”

  Captain Baegess said, “And so your suggestion is that we put the ship into a ballistic orbit, so that we can shut down all engines and overhaul all the separators and plates? I have to agree it would fix the problem.”

  “It would certainly be the safest thing to do,” Azir agreed.

  I could see the bony plates of Krurix’s shoulders relax, and the hair of his crest lie down. He had clearly been scared out of his mind, arguing with the senior officers at a time like this. I had to admit that I couldn’t be sure I’d have had his courage, or his perception. Well, maybe he was useful after all, even if he wasn’t likable. I resolved to listen to him more.

  At least when he wasn’t making terrible jokes about orders.

  Streeyeptin climbed in and said, “Is there some delay? Everyone below would like to know what we’re doing.”

  Captain Baegess glanced up. “Assistant Krurix has found a major risk to the ship and suggested a fix for it. We’re trying to decide what to do about it.”

  The Political Officer gestured impatiently. “We aren’t crashing, are we?”

  “Not yet.” Baegess’s voice was flat. “But it’s serious.”

  “We’ve got a mission.” Streeyeptin pointed out. “Are we starting our investigation yet?”

  “We will as soon as I’m sure we’ve secured our survival,” Baegess said. “Self-preservation and safe return is the first priority—that’s in the orders, too. And this is that serious.”

  So naturally it all had to be explained to Streeyeptin all over again, in much simpler terms. Eventually he nodded. “Yes, I see the point. But we will proceed with the original plan. I’m not sure even now, after all that babble, why you give so much weight to that argument—however ingenious, and Assistant Krurix, it does speak well of you that you are constantly thinking—when you consider two obvious points. The People’s Space Exploration Foundation built this ship to make the round trip, with a wide margin of error, and thus we are much less than halfway through the distance it was designed to cover. Therefore, the probability of any serious problem is negligible. Moreover, we’ve just arrived here safely after traveling an enormous distance, and by your own acknowledgment, after the anomalies, the engine is now running normally.

  “Therefore the chances that anything is wrong are very slim. That being the case, then our orders are very clear. We are to proceed at once to determine what happened to the crew of Wahkopem Zomos. Once that is determined, we are then to make a brief determination about whether the Nisuan Republic should attempt to plant a colony here, and then to return home. That is all that we are authorized to do; since making sure the engine is working properly is clearly a task for the homeward journey, we will do the maneuver you suggest just before our departure, or sooner if a suitable block of time during which we don’t need regular access to the ship should come along.

  “You see, it’s all there in the orders, if you just pay attention to them.” He looked around the room, a satisfied expression. With a sinking heart, I realized that he had just resolved the matter, as far as he was concerned.

  Captain Baegess sighed. “We are also obligated for self-preservation and safe return. We have no experience with catastrophic failure of a zero-point energy laser. For all we know it could happen anytime. If it happened now, my suspicion is that Krurix is right—we’d all die.”

  Streeyeptin’s expression was cheerful but not pleasant. “It seems to me that this is
the first time, in quite a while, that you have been interested in the original orders.”

  Captain Baegess surely understood the threat, but he didn’t let that show. He merely said, “There is no question of Egalitarian Republic’s loyalty.”

  Streeyeptin seemed very pleased. “Obviously.” I suppose in his line of work, he’d gotten used to being happy with everyone just quietly acquiescing, with all those expressionless faces that said yes and carefully did not tell him what they thought.

  3

  BEPEMM’S VOICE CAME OVER the intercom. “Captain, I have made contact with Wahkopem Zomos. It’s right in the orbit where it was supposed to be. The access codes all worked, too. I’m ready to start downloading everything from Wahkopem Zomos’s main computer.”

  Before Captain Baegess could reply, Streeyeptin picked up the mouthpiece. “Do it,” he said. “Then search all documents from the landing forward, back-referring as you need to, and see if you can establish what happened.” Technically he wasn’t supposed to be giving orders to Bepemm, or any other crew member, directly, but no doubt he felt that he needed to assert his authority after the dispute that had just ended.

  One of the first things a citizen of the Republic learns is that you don’t argue with a political officer. “Right away, sir,” Bepemm said, her voice suddenly crisply obedient.

  “And while we’re waiting for Bepemm’s report, Captain, I strongly suggest you have your assistant get the rovers down on the ground and operating. We have a mystery to clear up here, and the people who sent us don’t like mysteries.”

  Captain Baegess nodded to me, and I turned around in my seat, powered up the utility console, and configured it to drive the rover. “Krurix,” I said, “I can use your help if Azir doesn’t need you further—pull up a seat.”