Hidden Variables

by Charles Sheffield

  I was getting goose bumps along the back of my neck. I knew the performance of the unmanned med ships. They would zip you from inside the orbit of Mercury out to Pluto in a couple of days, standing start to standing finish. Once in a while you'd get a passenger on them—accident or suicide. The flattened thing that they unpacked at the other end showed what the human body thought of a hundred gee.

  "What would happen if the drives went off suddenly?" I said.

  "You mean when the capsule is up against the disk—at maximum thrust?" Wenig shook his head. "We designed a safeguard system to prevent that, even on the prototypes. If there were a sign of the drive cutting off, the capsule would be moved back up the column, away from the disk. The system for that is built-in."

  "Yeah. But McAndrew hasn't come back." I had the urge to get on our way. "I've seen built-in-safe systems before. The more foolproof you think something is, the worse the failure when it happens. Can't we get moving?"

  "Come on." Wenig stood up. "Any teacher will tell you, you can't get much into an impatient learner. I'll give you the rest of the story as we go. We'll head out along the same path as McAndrew did—that's plotted out in the records back here."

  "You think McAndrew went along with the nominal flight plan?"

  "We know he didn't." Wenig looked a lot less sure of himself. "You see, when the drives are on maximum the plasma round the living-capsule column interferes with radio signals. Fifty hours after they left the Institute, the Merganser was tracked from Triton Station. McAndrew came back into the Solar System, decelerating at fifty gee. He didn't cut the drive at all—just went right through the System and accelerated out again in a slightly different direction. We got the log, but we have no idea what he was doing. There was no way to get a signal to him or from him with the drive on."

  "So they got all the way up to the maximum drive! And they came back here. God, why didn't Limperis tell me that when we were in the first meeting?" I went to the locker and pulled out a suit. "He took it up all the way, fifty gee or better. Let's get after him. If he kept that up, he'll be halfway to Alpha Centauri by now."

  The living-capsule was about three meters across and simply furnished. I was surprised at the amount of room, until Wenig pointed out to me how equipment and supplies that could take higher accelerations were situated on the outside of the capsule, on the side away from the gravity disk.

  We had started with McAndrew's flight plan for only a few minutes when I took Limperis at his word that I'd be boss and changed the procedure. If we were to reach McAndrew, the less time we spent shooting off in the wrong direction, the better. He had come right through the System, and we ought to head in the direction that he was last seen to be heading.

  "I'll take us up to fifty gee," said Wenig. "That way, we'll experience the same perturbing forces as the Merganser did. All right?"

  "Christ, no." My stomach turned over. "Not all right. Look, we don't know what happened to Mac, but chances are it was some problem with the ship. If we do just what he did, we may finish up with the same trouble."

  Wenig took his hands off the controls and turned to me, palms spread. "But then what can we do? We don't know where they were going, all we can do is try and follow the same track."

  "I'm not sure. All I know is what we're not going to do—and we're not trying for top acceleration. Didn't you say you'd flown Merganser at twenty gee?"

  "Several times."

  "Then take us out along Mac's trajectory at twenty gee until we're outside the System. Then cut the drive. I want to use our sensors, and we won't be able to do that from the middle of a ball of plasma."

  Wenig looked at me. I know he was mentally accusing me of cowardice. "Captain Roker," he said quietly. "I thought we were in a hurry. We may be weeks following Merganser the way you are proposing."

  "Yeah. But we'll get there. Can Mac's support system last that long?"

  "Easily."

  "Then don't let's kick it around any more. Let's do it. Twenty gee, as soon as you can give it to us."

  * * *

  The Dotterel worked like a dream. At twenty gee acceleration relative to the Solar System, we didn't feel anything unusual at all. The disk pulled us towards it at twenty-one gee, the acceleration of the ship pulled us away from it at twenty gee, and we sat there in the middle at a snug and comfortable standard gravity. I couldn't even feel the tidal forces, though I knew they were there. We had poor communications with the Penrose Institute, but we'd known that and expected to make up for it when we cut the drive.

  Oddly enough, the first phase of the trip wasn't scary—it was boring. I wanted to get up to a good cruise speed before we coasted free. It gave me the chance to probe another mystery—one that seemed at least as strange as the disappearance of the Merganser.

  "What were you doing at the Institute, allowing Nina Velez aboard the ship?"

  "She heard that we were developing a new drive—don't ask me how. Maybe she saw the Institute's budget." Wenig sniffed. "I don't trust the security at the USF Headquarters."

  "And you let her talk her way in, and you forced McAndrew to take her with him on a test flight?"

  If I sounded mad, I felt madder. Mac's life meant more than the dignity of some smooth-assed bureaucrat in the Institute's front office.

  Dr. Wenig looked at me coldly. "I think you misunderstand the situation. Nina Velez was not forced onto Professor McAndrew by the "front office"—for one thing, we have no such thing. The Institute is run by its members. You want to know why Miss Velez is on board the Merganser? I'll tell you. McAndrew insisted that she go with him."

  "Bullshit!" There were some things I couldn't believe. "Why the hell would Mac let himself go along with that? I know him, even if you don't. Over his dead body."

  Wenig sighed. He was leaning on a couch across from me, sipping a glass of white wine—no hardship tours for him.

  "Four weeks ago I'd have echoed your comments exactly," he said. "Professor McAndrew would never agree to such a thing, right? But he did. Putting this simply, Captain Roker, it is a case of infatuation. A bad one. I think that—"

  He stopped, outraged. I had started to laugh, in spite of the seriousness of our situation.

  "What's so funny, Captain?"

  "Well." I shrugged. "The whole thing's funny. Not funny, it's preposterous. McAndrew is a great physicist, and Nina Velez may be the President's daughter, but she's just a young newswoman. Anyway, he and I—he wouldn't—"

  Now I stopped. I wondered if Wenig was going to get up and hit me, he looked so mad.

  "Captain Roker, I don't like your insinuation," he said. "McAndrew is a physicist—so am I. You may not be smart enough to realize it, but physics is a field of study, not a surgical operation. Castration isn't part of the Ph.D. exams, you know." His tone dripped sarcasm. I wouldn't have liked a two-month trip to Titan with young Dr. Wenig.

  "Anyway," he went on. "You have managed to jump to a wrong conclusion. It was not Professor McAndrew who suffered the initial infatuation. It was Nina Velez. She thinks he is wonderful. She came to do an interview, and before any of us knew what was going on she was in his office all day. All night, too, after the first week."

  I was wrong. I know that now, and I think I knew it then, but I was too peeved to make an immediate apology to Wenig. Instead, I said, "But if she was the one that wanted him, couldn't he just throw her out?"

  "Nina Velez?" Wenig gave a bark of laughter. "You've never met her, I assume? She's a President's daughter, and whatever Nina wants, Nina gets. She started it, but inside a couple of days she had Professor McAndrew behaving like a true fool. It was disgusting, the way he went on."

  (You're jealous, Wenig, I said, jealous of Mac's good luck—but I said it to myself.)

  "And she persuaded McAndrew to let her go out on the Merganser? What were the rest of you doing?"

  He reddened. "Professor McAndrew was not the only one behaving like a fool. Why do you think Limperis, Siclaro and I feel like murderers? The tw
o women on the team, Gowers and Macedo, insisted that Nina Velez should not go near the ships. We overruled them. Now, Captain Roker, maybe you see why each of us wanted to come after McAndrew. We drew lots, and I was the winner.

  "And maybe you should think of one other thing. While you are looking at our motives, and laughing at them, maybe you ought to look at your own. You look angry. I think you are jealous—jealous of Nina Velez."

  It's a good thing that we had to follow our flight plan at that point, and prepare to cut the drive, or I don't know what I would have done to Dr. Wenig. I'm a shade taller than he is, and I outweigh him by maybe ten pounds, but he looked fit and wiry. It wouldn't have been a foregone conclusion, not at all.

  Our descent into savagery was saved by the insistent buzzer of the computer, telling us to be ready for the drive reduction. We sat there, furious and not looking at each other, as the acceleration was slowly throttled back and the capsule moved away from the disk to resume its free-flight position two hundred and fifty meters behind it. The move took ten minutes. By the time it was over we had cooled off. I managed a graceless apology for my implied insults, and Wenig just as uncomfortably accepted it and said that he was sorry for what he had been saying and thinking.

  I didn't ask him what he had been thinking—there was a hint that it was much worse than anything that he had said.

  We had cut the drive at a little more than one hundred astronomical units from the Sun and were coasting along at a quarter of the speed of light. The computer gave us automatic Doppler compensation, so that we could hold an accurate communication link back to the Institute, through Triton Station. Conversation wasn't easy, because the round-trip delay for signals was almost twenty-eight hours—all we expected to be able to do was send "doing fine" messages to Limperis and the others.

  Our forward motion was completely imperceptible, though I fancied that I could see a reddening of stars astern and a bluer burn to stars ahead of us. We were well beyond the edge of the planetary part of the System, out where only the comets and the kernels lived. I put all our sensors onto maximum gain and Wenig and I settled in to a quiet spell of close watching. He had asked me what we were looking for. I had told him the truth: I had no idea, of what or when.

  * * *

  We crept on, farther and farther out. I don't know if you can actually creep at a quarter of light speed, but that's the way it felt; blackness, the unchanging stars, and a dwarfed Solar System far behind us.

  Our eyes were all wide open: radio receivers, infrared scanners, telescopes, flux meters, radar and mass detectors. For two days we found nothing, no signal above the hiss and shimmer of the perennial interstellar background. Wenig was growing more impatient, and his tone was barely civil. He wanted us to get the drive back on high, and dash off after McAndrew—wherever that might be.

  He was fidgeting on his bunk and ignoring the scopes when I caught the first trace.

  "Dr. Wenig. What am I seeing? Can you tune that IR receiver?"

  He came alert and was over to the console in a single movement. After a few seconds of adjustment he shook his head and swore. "It's natural, not man-made. Look at that trace. We're seeing a hot collapsed body. About seven hundred degrees, that's why there's peak power in the five micrometer band. We can call back to Limperis if you like, but he's sure to have it in his catalog already. There must be lots of these within a few days flight of us."

  He left the display and slumped back on his bunk. I went over and stared at it for a couple of minutes. "Would McAndrew know that this is here?"

  That made him think instead of just brooding. "There's a good chance that he would. Collapsed and high-density matter is Doctor Limperis's special study, but McAndrew probably put a library of them into Merganser's computer before he left. He wouldn't want to run into something unexpected out here."

  "We have McAndrew's probable trajectory stored there too?"

  "We know how he left the System, where he was heading. If he cut the drive, or turned after he was outside tracking range, we don't have any information on it."

  "Never mind that. Give me the library access codes, and let me get at the input console. I want to see if Mac's path shows intersection with any of the high-density objects out here."

  Wenig looked skeptical. "The chances of such a close encounter are very small. One in millions or billions."

  I was already calling up the access sequence. "By accident? I'd agree with you. But McAndrew must have had some reason to fly back through the System, and make the slight course change that you recorded. I think he was telling us where he was going. And the only place he could have been going between here and Sirius would be one of the collapsed bodies out in the Halo."

  "But why?" Wenig was standing at my shoulder, fingers twitching.

  "Don't know that." I stood up. "Here, you do it, you must have had plenty of experience with Dotterel's computer. Set it for anything that would put Merganser within five million kilometers of a high-density body. That's as close as I think we can rely on trajectory intersection."

  Wenig's fingers were flying over the keys—he should have been a concert pianist. I've never seen anybody handle a programming sequence at that rate. While he was doing it the com-link whistled for attention. I turned to it, leaving Wenig calling out displays and index files.

  "It's Limperis," I said. "Problems. President Velez is starting to breathe down his neck. Wants to know what has happened to Nina. When will she be back? Why did Limperis and the rest of you let her go on a test trip? How can the Institute be so irresponsible?"

  "We expected that." Wenig didn't look up. "Velez is just blowing off steam. There's no way that any other ship could get out here to us in less than three months. Does he have anything useful to suggest?"

  "No. He's threatening Limperis with punitive measures against the Institute. Says he'll want a review of the whole organization."

  "Limperis is asking for our reply?"

  "Yes."

  Wenig keyed in a final sequence of commands and sat back in his seat. "Tell him Velez should go fuck himself. We've got enough to do without interference."

  I was still reading the incoming signals from Triton Station. "I think Dr. Limperis has already sent that message to the President's Office, in not quite those words. We'd better get Nina back safely."

  "I know that." Wenig hit a couple of keys and an output stream began to fill the scope. "Here it comes. Closest approach distances for every body within five hundred AU, assuming McAndrew held the same course and acceleration all the way out. I've set it to stop if we get anything better than a million kilometers, and display everything that's five million or closer."

  Before I could learn how to read the display, Wenig banged both hands down on the desk and leaned forward,

  "Look at that!" His voice showed his surprise and excitement. "See it? That's HC-183. It's 322 AU from the Sun, and almost dead ahead of us. The computer shows a fly-by distance for Merganser too small to compute—that's an underflow where we ought to see a distance."

  "Suppose that McAndrew decelerated as he got nearer to it?"

  "Wouldn't make much difference, he'd still be close to rendezvous—speeds in orbit are small that far out. But why would he want to rendezvous with HC-183?"

  I couldn't answer that, but maybe we were at least going to find Merganser. Even if it was only a vaporized trace on the surface of HC-183, where the ship hit it.

  "Let's get back with our drive," I said. "What's the mass of HC-183?"

  "Pretty high." Wenig frowned at the display. "We show a five thousand kilometer diameter and a mass that's half of Jupiter's. Must be a good lump of collapsed matter at the center of it. How close do you want to take us? And what acceleration for the drive?"

  "Give us a trajectory that lets us take a close look from bound orbit. A million kilometers ought to be enough. And keep us down to twenty gee or better. I'll send a message back to the Institute. If they have any more information on HC-183, we want it."


  * * *

  Wenig had been impatient before, when we weren't going anywhere in particular. Now that we had a target he couldn't sit still. He was all over our three-meter living-capsule, fiddling with the scopes, the computer, and the control console. He kept looking wistfully at the drive setting, then at me.

  I wasn't having any. I felt as impatient as he did, but when we had come this far I didn't want to find we'd duplicated all McAndrew's actions, including the one that might have been fatal. We smoothly turned after twenty-two hours, so our drive began to decelerate us, and waited out the interminable delay as we crept closer to the dark mass of HC-183. We couldn't see a sign of it on any of the sensors, but we knew it had to be there, hidden behind the plasma ball of the drive.

  When our drive went off and we were in orbit around the black mass of the hidden proto-planet, Wenig was at the display console for visible wavelengths.

  "I can see it," he shouted.

  My first feeling of relief and excitement lasted only a split second. There was no way we would be able to spot the Merganser from a million kilometers out.

  "What are you seeing? Infrared emission from HC-183?"

  "No, you noodle. I can see the ship—McAndrew's ship."

  "You can't be. We'd have to be right next to it to be able to pick it up with our magnifications." I spun my seat around and looked at the screen.

  Wenig was laughing, hysterical with relief. "Don't you understand? I'm seeing the drive, not Merganser itself. Look at it, isn't it beautiful?"

  He was right. I felt as though I was losing my reason. McAndrew might have gone into orbit about the body, or if he were unlucky he might have run into it—but it made no sense that he'd be sitting here with the drive on. And from the look of the long tail of glowing plasma that stretched across twenty degrees of the screen, that drive was on a high setting.