Moment of Inertia

"Now," said the interviewer, "tell us just what led you to the ideas for the inertia-less drive."

She was young and vulnerable-looking, and I think that was what saved her from a hot reply. As it was, McAndrew just shook his head and said quietly—but still with feeling—"Not the inertia-less drive. There's no such thing. It's a balanced drive."

She looked confused. "But it lets you accelerate at more than fifty gees, doesn't it? By making you so you don't feel any acceleration at all. Doesn't that mean you must have no inertia?"

McAndrew was shaking his head again. He looked pained and resigned. I suppose that he had to go through this explanation twice a day, every day of his life, with somebody.

I leaned forward and lowered the sound on the video unit. I had heard the story too often, and my sympathies were all with him. We had direct evidence that the McAndrew drive was anything but inertia-less. I doubt if he'll ever get that message across to the average person, even though he's most people's idea of the `great scientist,' the ultimate professor.

I was there at the beginning of the whole thing. In fact, according to McAndrew I was the beginning. We had been winding our way back from the Titan Colony, travelling light as we usually did on the inbound leg. We had only four Sections in the Assembly, and only two of them carried power kernels and drive units, so I guess we massed about three billion tons for ship and cargo.

Halfway in, just after turnover point, we got an incoming request for medical help from the mining colony on Horus. I passed the word on to Luna Station, but we couldn't do much to help. Horus is in the Egyptian Cluster of asteroids, way out of the ecliptic, and it would take any aid mission a couple of weeks to get to them. By that time, I suspected their problem would be over—one way or another. So I was in a pretty gloomy mood when McAndrew and I sat down to dinner.

"I didn't know what to tell them, Mac. They know the score as well as I do, but they couldn't resist asking if we had a fast-passage ship that could help them. I had to tell them the truth, there's nothing that can get out there at better than two and a half gees, not with people on board. And they need doctors, not just drugs. Luna will have something on the way in a couple of days, but I don't think that will do it."

McAndrew nodded sympathetically. He knew that I needed to talk it out to somebody, and we've spent a lot of time together on those Titan runs. He's working on his own experiments most of the time, but I know when he needs company, too. It must be nice to be a famous scientist, but it can be lonely travelling all the time inside your own head.

"I wonder if we're meant for space, Mac," I went on—only half-joking. "We've got drives that will let us send unmanned probes out at better than a hundred gees of continuous acceleration, but we're the weak link. I could take the Assembly here up to five gee—we'd be home in a couple of days instead of another month—but you and I couldn't take it. Can't you and some of your staff at the Institute come up with a system so that we don't get crushed flat by high accelerations? A thing like that, an inertia-less drive, it would change space exploration completely."

I was wandering on, just to keep my mind off the problems they had out on Horus, but what I was saying was sound enough. We had the power on the ships, only the humans were the obstacle. McAndrew was listening to me seriously, but he was shaking his head.

"So far as I know, Jeanie, an inertia-less drive is a theoretical impossibility. Unless somebody a lot brighter than I am can come up with an entirely new theory of physics, we'll not see your inertia-less drive."

That was a pretty definitive answer. There were no people brighter than McAndrew, at least in the area of physics. If Mac didn't think it could be done, you'd not find many people arguing with him. Some people were fooled by the fact that he took time off to make trips with me out to Titan, but that was all part of his way of working.

If you deduce from this that I'm not up at that rarefied level of thought, you're quite right. I can follow McAndrew's explanations—sometimes. But when he really gets going he loses me in the first two sentences.

This time, his words seemed clear enough for anyone to follow them. I poured myself another glass of ouzo and wondered how many centuries it would be before the man or woman with the completely new theory came along. Sitting across from me, Mac had begun to rub at his sandy, receding hairline. His expression had become vacant. I've learned not to interrupt when he's got that look on his face. It means he's thinking in a way that I can't follow. One of the other professors at the Penrose Institute says that Mac has a mind that can see round corners, and I have a little inkling what he means by that.

"Why inertia-less, Jeanie?" said McAndrew after a few minutes.

Maybe he hadn't been listening after all. "So we can use high accelerations. So we can get people to go at the same speeds as the unmanned probes. They'd be flattened at fifty gee, you know that. We need an inertia-less drive so that we can stand that acceleration without being squashed to a mush."

"But that's not the same thing at all. I told you that a drive with no inertia isn't possible—and it isn't. What you're asking for, now, it seems to me that we should be able . . ."

His voice drifted off to nothing, he stood up, and without another word he left the cabin. I wondered what I'd started.

If that was the beginning of the McAndrew drive—as I think it was—then, yes, I was there at the very beginning.

* * *

So far as I could tell, it wasn't only the beginning. It was also the end. Mac didn't talk about the subject again on our way in to Luna rendezvous, even though I tried to nudge him a couple of times. He was always the same, he didn't like to talk about his ideas when they were "half-cooked," as he called it.

When we got to Luna, McAndrew went off back to the Institute, and I took a cargo out to Cybele. End of story, and it gradually faded from my thoughts, until the time came, seven months later, for the next run to Titan.

For the first time in five years, McAndrew didn't make the trip. He didn't call me, but I got a brief message that he was busy with an off-Earth project, and wouldn't be free for several months. I wondered, not too seriously, if Mac's absence could be connected with inertia-less spaceships, and then went on with the cargo to Titan.

That was the trip where some lunatic in the United Space Federation's upper bureaucracy decided that Titan was overdue for some favorable publicity, as a thriving colony where culture would be welcomed. Fine. They decided to combine culture and nostalgia, and hold on Titan a full-scale, old-fashioned Miss & Mister Universe competition. It apparently never occurred to the organizers—who must have had minds that could not see in straight lines, let alone around corners—that the participants were bound to take the thing seriously once it was started. Beauty is not something that good-looking people are willing to take lightly. I had the whole Assembly filled with gorgeous, jealous contestants, screaming managers, horny and ever-hopeful newshounds from every media outlet in the System, and any number of vengeful and vigilant wives, lovers and mistresses of both sexes. On one of my earlier runs I took a circus and zoo out to Titan, but that was nothing compared with this trip. Thank Heaven that the ship is computer-controlled. All my time was spent in keeping some of the passengers together and the rest apart.

It also hadn't occurred to the organizers, back on Earth, that a good part of the Titan colony is the prison. When I saw the first interaction of the prisoners and the contestants I realized that the trip out to Titan had been a picnic compared with what was about to follow. I chickened out and went back to the ship until it was all over.

I couldn't really escape, though. When it was all over, when the winners had finally been chosen, when the protests and the counter-protests had all been lodged, when the battered remnants of the more persistent prisoners had been carried back to custody, when mayhem was stilled, and when the colonists of Titan must have felt that they had enjoyed as much of Inner System culture as they could stand for another twenty or thirty years, after all that it was my job to get the group back on board again, and home to Earth without further violence. The contestants hated their managers, the managers hated the judges, the judges hated the news media, and everyone hated the winners. It seemed to me that McAndrew may have had advance information about the trip, and drawn a correct conclusion.

I would like to have skipped it myself. Since I was stuck with it, I separated the Sections of the Assembly as much as I could, put everything onto automatic, and devoted myself to consoling one of the losers, a smooth-skinned armful from one of the larger asteroids.

We finally got there. On that day of rejoicing, the whole ghastly gaggle connected with the contest left the Assembly, I said a lingering farewell to my friend from Vesta—a most inappropriate origin for that particular contestant—and settled back for a needed rest.

It lasted for about eight hours. As soon as I called into the Com Center for news and messages, I got a terse summons on the com display: GO TO PENROSE INSTITUTE, L-4 STATION. MACAVITY.

Not an alarming message, on the face of it, but it worried me. It was from McAndrew, and I doubt if three people knew that I had given him that nickname when I found he was a specialist on theories of gravity ("Old Possum's Book Of Practical Cats" didn't seem to be widely read among Mac's colleagues).

Why hadn't he called me directly, instead of sending a com-link message? The fact that we were back from Titan would have been widely reported. I sat down at the terminal and placed a link to the Institute, person-to-person to McAndrew.

I didn't feel any better when the call went through. Instead of Mac's familiar face, I was looking at the coal-black complexion of Professor Limperis, the head of the Institute. He nodded at me seriously.

"Captain Roker, your timing is impressive. If we had received no response to Professor McAndrew's coded message in the next eight hours, we would have proceeded without you. Can you help?"

He hesitated, seeing my confused expression. "Did your message tell you the background of the problem?"

"Dr. Limperis, all I've had so far is half a dozen words—to go to the L-4 branch of the Institute. I can do that easily enough, but I have no idea what the problem is, or what use I could possibly be on it. Where's Mac?"

"I wish to God I could answer that." He sat silent for a moment, chewing on his lower lip, then shrugged. "Professor McAndrew insisted that we send for you—left a message specifically for you. He told us that you were the stimulus for beginning the whole thing."

"What whole thing?''

He looked at me in even greater surprise. "Why, the high acceleration drive—the balanced drive that McAndrew has been developing for the past year. McAndrew has disappeared testing the prototype. Can you come at once to the Institute?"

The trip out to the Institute, creeping along in the Space Tug from Luna Station, was one of the low points of my life. There was no particular logic to it—after all, I'd done nothing wrong. But I couldn't get rid of the feeling that I'd wasted a critical eight hours after the passengers had left the Assembly. If I hadn't been obsessed with sex on the trip back, maybe I would have gone straight to the com-link instead of taking a sleep break. And maybe then I would have been on my way that much earlier, and that would have been the difference between saving Mac and failing to save him . . .

You can see how my mind was running. Without any real facts, you can make bears out of bushes just as well in space as you can on Earth. All I had been told by Limperis was that McAndrew had left a week earlier on a test of the prototype of a new ship. If he was not back within a hundred and fifty hours, he had left that terse coded message for me, and instructions—orders might be a better word—to take me along on any attempted search for him.

Dr. Limperis had been very apologetic about it. "I'm only quoting Professor McAndrew, you understand. He said that he didn't want any rescue party setting out in the Dotterel if you weren't part of it. He said"—Limperis coughed uncomfortably—"we had a real need for your commonsense and natural cowardice. We'll be waiting for you here as soon as you can arrange passage. The least we can do for Professor McAndrew in the circumstances is to honor his wishes on this."

I couldn't decide if I was being complimented or not. As L-4 Station crept into view on the forward screen, I peered at it on highest magnification, trying to see what the rescue ship looked like. I could see the bulk of the Institute structure but no sign of anything that ought to be a ship. I had visions of a sort of super-Assembly, a huge cluster of electromagnetically linked spheres. All I could see were living quarters and docking facilities, and, as we came in to dock, a peculiar construction like a flat, shiny plate with a long thin spike protruding from the center. It looked nothing like any USF ship, passenger or cargo.

Limperis may have spent his whole life in pure research, but he knew how to organize for emergency action. There were just five people in our meeting inside the Institute. I had never met them in person, but they were all familiar to me through McAndrew's descriptions, and from media coverage. Limperis himself had made a life study of high-density matter. He knew every kernel below lunar mass out to a couple of hundred astronomical units—many of them he had visited, and a few of the small ones he had shunted back with him to the Inner System, to use as power supplies.

Siclaro was the specialist in kernel energy extraction. The Kerr-Newman black holes were well-understood theoretically, but efficient use of them was still a matter for experts. When the USF wanted to know the best way to draw off power, for drives or for general use, Siclaro was usually called in. His name on a recommendation was like a stamp of approval that few would think to question.

With Gowers there as an expert in multiple kernel arrays, Macedo as the System authority in electromagnetic coupling, and Wenig the master of compressed matter stability, the combined intellect in that one room in the Institute was overpowering. I looked at the three men and two women who had just been introduced to me, and felt like a gorilla in a ballet. I might make the right movements, but I wouldn't know what was going on.

"Look, Dr. Limperis," I said, "I know what Professor McAndrew wants, but I'm not sure he's right." Might as well hit them with my worries at the beginning, and not waste everybody's time. "I can run a ship, sure—it's not hard. But I've no idea how to run something with a McAndrew drive on it. Any one of you could probably do a better job."

Limperis was looking apologetic again. "Yes and no, Captain Roker. We could all handle the ship, any one of us. The concepts behind it are simple—a hundred and fifty years old. And the engineering has been kept simple, too, since we are dealing with a prototype."

"Then what do you want me for?" I won't say I was angry, but I was uneasy and unhappy, and there's a fine line between irritation and discomfort.

"Dr. Wenig will drive the Dotterel, he has handled it before in an earlier test. Actually, he handled the Merganser, the ship that Dr. McAndrew has disappeared in, but the Dotterel has identical design and equipment. Controlling the ship is easy—if everything behaves as we expected. If something goes wrong—and something must have gone wrong, or McAndrew would be back before this—then neither Dr. Wenig, nor any of the rest of us, has the experience that will be needed. We want you to tell Dr. Wenig what not to do. You've been through dangerous times before." He looked pleading. "Will you observe our actions, and use your experience to advise us?"

Uninvited, I flopped down into a seat and stared at the five of them. "You want me to be a bloody canary!"

"A canary?" Wenig was small and slight, with a luxuriant black mustache. He had a strong accent, and I think he was suspecting himself of a translation error.

"Right. Back when people used to go down deep in the earth to mine coal, they used to take a canary along with them. It was more sensitive to poisonous gases than they were. When it fell off the perch, they knew it was time to leave. The rest of you will fly the ship, and watch for me to fall off my seat."

They looked at each other, and finally Limperis nodded. "We need a canary, Captain Roker. None of us here knows how to sing at the right time. Will you do it?"

I had no choice. Not after Mac's personal cry for help. I could see one problem—I'd be telling them everything they did was dangerous. When you have a new piece of technology, it is risky, whatever you do with it.

"You mean you'll let me overrule all the rest of you, if I don't feel comfortable?"

"We would." Limperis was quite firm about it. "But the question will not arise. The Merganser and the Dotterel are both two-person ships. We saw no point in making them larger. Dr. Wenig will fly the Dotterel, and you will be the only other person aboard. It just takes one person to handle the controls. You will be there to advise of hidden problems."

I stood up. "Let's go. I don't think I can see danger any better than you can, but I may be wrong. If Mac's on his own out there, wherever he is, we'd better get moving. I'm ready when you are, Dr. Wenig."

Nobody moved. Maybe McAndrew and Limperis were right about my antennae, because at that moment I had a premonition of new problems. I looked around at the uncomfortable faces.

"Professor McAndrew isn't actually alone on the Merganser." It was Emma Gowers who spoke first. "He has a passenger with him on the ship."

"Someone from the Institute?"

She shook her head. "Nina Velez is with him."

"Nina Velez? You don't mean President Velez's daughter—the one with AG News?"

She nodded. "The same."

I sat down again in my chair. Hard. Maybe the Body-beautiful run to Titan had been an easier trip than I had realized.

* * *

Wenig may have come to piloting second-hand, but he certainly knew his ship. He wanted me to know it, too. Before we left the Institute, we'd done the lot—schematics, models, components, power, life support, mechanicals, electricals, electronics, controls, and backups.

When the ship was explained to me, I decided that McAndrew didn't really see round corners when he thought. It was just that things were obvious to him before they were explained, and obvious to other people afterwards. I had been saying "inertia-less" to Mac, and he had been just as often saying "impossible." But we hadn't been communicating very well. All I wanted was a drive that would let us accelerate at multiple gees without flattening the passengers. To McAndrew, that was a simple requirement, one that he could easily satisfy—but there was no question of doing away with inertia, of passengers or ship.

"Take it back to basics," said Wenig, when he was showing me how the Dotterel worked. "Remember the equivalence principle? That's at the heart of it. There is no way of distinguishing an accelerated motion from a gravitational field force, right?"

I had no trouble with that. It was freshman physics. "Sure. You'd be flattened just as well in a really high gravity field as you would in a ship accelerating at fifty gee. But where does it get you?"

"Imagine that you were standing on something with a hefty gravity field—Jupiter, say. You'd experience a downward force of about two and a half gee. Now suppose that somebody could accelerate Jupiter away from you, downwards, at two and a half gee. You'd fall towards it, but you'd never reach it—it would be accelerating at the same rate as you are. And you'd feel as though you were in free fall, but so far as the rest of the Universe is concerned you'd be accelerating at two and a half gee, same as Jupiter. That's what the equivalence principle is telling us, that acceleration and gravity can cancel out, if they're set up to be equal and opposite."

As soon as you got used to Wenig's accent, he was easy to follow—I doubt if anybody could get into the Institute unless he was more than bright enough to explain concepts in easy terms.

I nodded. "I can understand that easily enough. But you've just replaced one problem with a worse one. You can't find any drive in the Universe that could accelerate Jupiter at two and a half gee."

"We cannot—not yet, at any rate. Luckily, we don't need to use Jupiter. We can do it with something a lot smaller, and a lot closer. Let's look at the Dotterel and the Merganser. At McAndrew's request I designed the mass element for both of them."

He went across to the window that looked out from the inside of the Institute to raw space. The Dotterel was floating about ten kilometers away, close enough to see the main components.

"See the plate on the bottom? It's a hundred meter diameter disk of compressed matter, electromagnetically stabilized and one meter thick. Density's about eleven hundred and seventy tons per cubic centimeter—pretty high, but nothing near as high as we've worked with here at the Institute. Less than you get in anything but the top couple of centimeters of a neutron star, and nowhere near approaching kernel densities. Now, if you were sitting right at the center of that disk, you'd experience a gravitational acceleration of fifty gee pulling you down to the disk. Tidal forces on you would be one gee per meter—not enough to trouble you. If you stayed on the axis of the disk, and moved away from it, you'd feel an attractive force of one gee when you were two hundred and forty-six meters from the center of the disk. See the column growing out from the disk? It's four meters across and two hundred and fifty meters long."

I looked at it through the scope. The long central spike seemed to be completely featureless, a slim column of grey metal.

"What's inside it?"

"Mostly nothing." Wenig picked up a model of the Dotterel and cracked it open lengthwise, so that I could see the interior structure. "When the drives are off, the living-capsule is out here at the far end, two hundred and fifty meters from the dense disk. Gravity feels like one gee, toward the center of the disk. See the drives here, on the disk itself? They accelerate the whole thing away from the center column, so the disk stays flat and perpendicular to the motion. The bigger the acceleration that the drives produce, the closer to the disk we move the living-capsule up the central column here. We keep it so the total force in the capsule, gravity less acceleration, is always one gee, toward the disk."

He slid the capsule along an electromechanical ladder closer to the disk. "It's easy to compute the right distance for any acceleration—the computer has it built-in, but you could do it by hand in a few minutes. When the drives are accelerating the whole thing at fourteen gee, the capsule is held a little less than fifty meters from the disk. I've been on a test run in the Merganser where we got up to almost twenty gee. Professor McAndrew intended to take it up to higher accelerations on this test. To accelerate at thirty-two gee, the capsule must be about twenty meters from the disk to keep effective gravity inside to one gee. The plan was to take the system all the way up to design maximum—fifty gee thrust acceleration, so that the passengers in the capsule would be right up against the disk, and feel as though they were in free fall. Gravity and thrust accelerations will exactly balance."

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 life 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 half-way 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?"


"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 two 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, infra-red 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?"


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? Infra-red 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.

"Give me a Doppler read-out," I said. "Let's find out what sort of orbit he's in. Damn it, what's he doing there, sight-seeing?"

Now that it looked as though we had found them, I was irrationally angry with McAndrew. He had brought us haring out beyond the limits of the System, and he was sitting there waiting when we arrived. Waiting, and that was all.

Wenig had called up a display and was sitting there staring at it in perplexity. "No motion relative to HC-183," he said. "He's not in an orbit around it, he's got the ship just hanging there, with the drive balancing the gravitational attraction. Want me to take us alongside, so we can use a radar signal? That's the only way he'll hear us through the drive interference."

"I guess we'll have to. Take us up close to them." I stared at the screen, random thoughts spinning around my head. "No, wait a minute. Damn it, once we set up the computer to take us in there, it will do automatic drive control. Before we go in, let's find out what we're in for. Can you estimate the strength of HC-183's gravitational attraction at the distance that Merganser is at? Got enough data for it?"

"Give me a second." Wenig's fingers flew over the console again. If he ever decided that he didn't want to work at the Penrose Institute, he'd make the best space-racer in the System.

He looked at the output for a second, frowned, and said, "I think I must have made an error."


"I'm coming up with a distance from the surface of about nine thousand kilometers. That means the Merganser would be feeling a pull of fifty gee—their drive would be full on, as high as it's designed to go. It wouldn't make sense for them to hang there like that, on full drive. Want to go on down to them?"

"No. Hold it where we are." I leaned back and closed my eyes. "There has to be a pattern to what Mac's been doing. He went right through the System back there with the drive full on, now he's hanging close in to a high-density object with the drive still full on. What the hell's he up to?"

"You won't find out unless we can get in touch with him." Wenig was sounding impatient again. "I say we should go on down there. Now we know where he is it's easiest to just go and ask him."

It was hard to argue with him, but I couldn't get an uneasy feeling out of the back of my head. Mac was holding a constant position, fifty gees of thrust balancing the fifty gee pull of HC-183. We couldn't get alongside him unless we were willing to increase Dotterel's drive to a matching fifty gee.

"Give me five more minutes. Remember why I'm here. It's to keep you from doing anything too brave. Look, if we were to hang on our drive with a twenty gee thrust, how close could we get to the Dotterel?"

"We'd have to make sure we didn't fry them with our drive," said Wenig. He was busy for a couple of minutes at the computer, while I tried again to make sense of the pieces.

"We can get so we're about sixty thousand kilometers from them," said Wenig at last. "If we want to talk to them through the microwave radar link, the best geometry would be one where we're seeing them side-on. We'd have decent clearance from both drives there. Ready to do it?"

"One minute more." I was getting a feeling, a sense that everything that McAndrew had done had been guided by a single logic. "Look, I asked you what would happen if the drive failed when the life capsule was up close to the mass disk, and you said the system would move the capsule back out again. But look at it the other way round now. Suppose the drive works fine—and suppose it was the system that's supposed to move the life-capsule up and down the column that wouldn't work? What would that do?"

Wenig stroked at his luxuriant mustache. "I don't think it could happen, the design looked good. If it did, everything would depend where the capsule stuck."

"Suppose it stuck up near the disk, when the ship was on a high-thrust drive."

"Well, that would mean there was a big gravitational acceleration. You'd have to cancel it out with the drive, or the passengers would be flattened." He paused. "It would be a bugger. You wouldn't dare to turn the drive off—you'd need it on all the time, so that your acceleration compensated for the gravity of the disk."

"Damn right. If you couldn't get yourself farther from the disk, you'd be forced to keep on accelerating. That's what happened to the Merganser, I'll bet my pension on it. Get the designs of the capsule movement-train up on the screen, and let's see if we can spot anything wrong with it."

"You're an optimist, Captain Roker." He shrugged. "We can do it, but those designs have been looked at twenty times. Look, I see what you're saying, but I find it hard to swallow. What was McAndrew doing when he came back through the system and then out again?"

"The only thing he could do. He couldn't switch the drive off, even though he could turn the ship around. He could fly off to God knows where in a straight line—that way we'd never have found him. Or he could fly in bloody great circles, and we'd have been able to see him but never get near to him for more than a couple of minutes at a time—there's no other manned ship that could match that fifty gee thrust. Or he could do what he did do. He flew back through the System to tell us the direction he was heading, out to HC-183. And he balanced here on his drive tail, and sat and waited for us to get smart enough to figure out what he was doing."

I paused for breath, highly pleased with myself. Out of a sphere of trillions of cubic miles, we had tracked the Merganser to its destination. Wenig was shaking his lead and looking very unhappy.

"What's wrong," I said cockily. "Find the logic hard to follow?"

"Not at all. A rather trivial exercise." He looked down his nose at me. "But you don't seem able to follow your own ideas to a conclusion. McAndrew knows all about this ship. He knows it can accelerate at the same rate as Merganser. So your idea that he couldn't fly around in big circles and wait for us to match his position can't be right—the Dotterel could do that."

He was right.

"So why didn't Mac do that? Why did he come out all this way?"

"I can only think of one answer. He's had the chance to look at the reason the life capsule can't be moved back along the axis, so the drive mustn't be switched off. And he thinks that this ship has the same problem."

I nodded. "See now why I wouldn't let you take the Dotterel all the way up to fifty gee?"

"I do. You were right, and I would have taken us into trouble if you hadn't been along. Now then"—Wenig looked gloomier than ever at some new thought—"let's take the logic a step farther. McAndrew is hanging down there near HC-183 in a fifty gee gravity field. We can't get there to help him unless we do the same, and we're agreed that we dare not do that, or we'll end up with the same difficulty that he has, and we won't be able to turn off the drive."

I looked out of the port, toward the dark bulk of HC-183 and the Merganser, hovering on its plume of high-temperature plasma. Wenig was right. We daren't go down there.

"So how are we going to get them out?"

Wenig shrugged, "I wish I could tell you. Maybe McAndrew has an answer. If not, they're as inaccessible as if they were halfway to Alpha Centauri and still accelerating. We've got to get into communication with them."

* * *

When I was about eleven years old, just before puberty, I had a disturbing series of dreams. Night after night, for maybe three months, I seemed to wake on the steep face of a cliff. It was dark, and I could barely see handholds and toeholds in the rock.

I had to get to the top—something was hidden below, invisible behind the curve of the black cliff face. I didn't know what it was, but it was awful.

Every night I would climb, as carefully as I could; and every night there would come a time when I missed a handhold, and began to slide downwards, down into the pit and the waiting monster.

I woke just as I reached the bottom, just as I was waiting for the first sight of my pit beast.

I never saw it. Puberty arrived, sex dreams replaced my fantasy. I forgot all about the cliff face, the terror, the feeling of force that could not be resisted. Forgot it totally—except that dream memories never disappear completely, they lie at some deep submerged level of the mind, until something pulls them out again.

And here I was again, back on the same cliff face, sliding steadily to my fate, powerless to prevent it. I woke up with my heart rate higher by thirty beats a minute, with cold perspiration on my forehead and neck. It took me a long time to return to the present, to banish the bygone fall into the pit.

I finally forced myself up to full consciousness and looked at the screen above me. The purple blaze of a plasma drive danced against the black backdrop of HC-183 and its surrounding star field. It hung there, falling forever but suspended on the feathery stalk of the drive exhaust. I lay there for about ten minutes, just watching, then looked across at Wenig. He was staring at me, his eyes unblinking.

"Awake at last," He made a sort of coughing noise, something that I think was intended to be a laugh. "You're a cool one, Captain Roker. I couldn't sleep with that hanging there"—he jerked his thumb at the screen—"even if you doped me up with everything in the robodoc."

"How long did I sleep?"

"About three hours. Ready to give up now?"

I was. It had been my idea, an insistence that we ought to try and get some sleep before we did the next phase of our maneuver around HC-183. Wenig had opposed it, had wanted to go on at once, but I thought we'd benefit from the rest. So I was wrong.

"I'm ready." My eyes felt as though they'd been filled with grit, and my throat was dry and sore, but talking about that to Wenig wouldn't do much for McAndrew or Nina Velez. "Let's get into position and try the radar."

While Wenig juggled us over to the best position, sixty thousand kilometers from HC-183 and about the same distance from the Merganser, I wondered again about my companion. They had drawn lots to come with me, and he had won. The other four scientists back at the Institute seemed a little naive and unworldly, but not Wenig. He was tough and shrewd, and I had seen the speed of those hands, dancing over the keyboard. Had he done a bit of juggling when they drew lots, a touch of hand-faster-than-the-eye?

I thought of his look when he spoke about Nina. If McAndrew was infatuated, perhaps Wenig shared the spell. Something strong was driving him along, some force that could keep him awake and alert for days on end. I wouldn't know if I was right or not unless we could find a way to haul Merganser back out of the field. The ship still hovered over its pendant of blue ionized gases, motionless as ever.

"How about this?" Wenig interrupted my thoughts. "I don't think I can get the geometry any better than it is now."

We were hanging there too, farther out from the proto-planet than the Merganser but close enough to see the black disk occulting the star field. We could beam short bursts of microwaves at our sister ship and hope there was enough signal strength to bore through the sheaths of plasma emitted by the drives. It would be touch and go—I had never tried to send a signal to an unmanned ship on high-drive, but our signal-to-noise ratio stood right on the borderline of system acceptance. As it was, we'd have to settle for voice-links only.

I nodded, and Wenig sent out our first pulses, the simple ship ID codes. We sent it for a couple of minutes, then waited with our attention fixed on the screen.

After a while Wenig shook his head. "We're not getting through. It wouldn't take that long to respond to our signal."

"Send it with reduced information rate and more redundancy. We have to give McAndrew enough to filter out the noise."

He was still in send mode when the display screen began to crawl with green patterns of light. Something was coming in. The computer was performing a frequency analysis to pick out the signal content from the background, smoothing it, and speeding it up to standard communication rate. We were looking at the Fourier analysis that preceded signal presentation.

"Voice mode," said Wenig quietly.

"Merganser." The computer reconstruction of McAndrew's voice was slow and hollow. "This is McAndrew from the Merganser. We're certainly glad to hear from you, Dotterel. Well, Jeanie, what kept you?"

"Roker speaking." I leaned forward and spoke into the vocal input system—too fast, but the computer would take care of that at the other end. "Mac, we're hanging about sixty kay out from you. Is everything all right in Merganser?"


"No," broke in another voice. "Get us out of here. We've been stuck in this damned metal box for sixteen days now."

"Nina," said Wenig. "We'd love to get you out—but we don't know how. Didn't Dr. McAndrew tell you the problem?"

"He said we couldn't leave here until the ship you are on came for us."

Wenig grimaced at me and turned away from the input link. "I ought to have realized that. McAndrew hasn't told her the problem with the drives—not all of it."

"Maybe he knows an answer." I faced back to the microphone. "Mac, as we see it we shouldn't put the Dotterel up as high as fifty gee thrust. Correct?"

"Of course." McAndrew sounded faintly surprised at my question. "Why do you think I went to such lengths to get to this holding position out here? When you go to maximum setting for the drive, the electromechanical coupling for moving the life capsule gets distorted, too."

"How did we miss it on the design?" Wenig sounded unconvinced.

"Remember the last-minute increase in stabilizing fields for the mass plate?"

"It was my recommendation—I'm not likely to forget it."

"We recalculated the effects on the drive and on the exhaust region, but not the magnetostrictive effects on the life-support column. We thought they were secondorder changes."

"And they're not? I ought to be drawn and quartered—that was my job!" Wenig was sitting there, fists clenched and face red.

"Was it now? Och, your job, eh? And I've been sitting here thinking all this time it was my job." For someone in a hopeless position thirty billion miles from home, McAndrew sounded amazingly cool. "Come on now, we can sort out whose doing it was when we're all back at the Institute."

Wenig looked startled, then turned to me again. "Go along with him on this—I'm sure he's doing it for Nina's sake. He doesn't want her worried."

I nodded—but this time I was unconvinced. Mac must have something hidden away inside his head, or not even Nina Velez would justify his optimistic tone.

"What should we do, Mac?" I said. "We'd get the same effects if we were to accelerate too hard. We can't get down to you, and you can't get up to us without accelerating out past us. How are we going to get you out of there?"

"Right." The laugh that came over the com link sounded forced and hollow, but that may have been just the tone that the computer filters gave it. "You might guess that's been on my mind too. The problem's in the mechanical coupling that moves the life capsule along the column. It's easy enough to see, once you imagine that you've had a two millimeter decrease in column diameter—that's the effects of the added field on the mass plate."

Wenig was already calling the schematics out onto a second display. "I'll check that. Keep talking."

"You'll see that when the drive's up to maximum, the capsule catches on the side of the column. It's a simple ratchet effect. I've tried varying the drive thrust up and down a couple of gee, but that won't free it."

"I see where you mean." Wenig had a lightpen out and was circling parts of the column for larger scale displays. "I don't see how we can do anything about it. It would take a lateral impact to free it—you'll not do it by varying your drive."

"Agreed. We need some lateral force on us. That's what I'm hoping you'll provide."

"What is all this?" It was Nina's voice again, and she sounded angry. "Why do you just keep on talking like that? Anybody who knew what he was doing would have us out by now—would never have got us into it in the first place if he had any sense."

I raised an eyebrow at Wenig. "The voice of infatuation? I think the bloom's off the rose down there."

He looked startled, then pleased, then excited—and then tried to appear nonchalant. "I don't know what McAndrew is getting at. How could we provide any help?" He turned to the input system. "Dr. McAndrew, how's that possible? We can't provide a lateral force on Merganser from here, and we can't come down safely."

"Of course you can." McAndrew's voice sounded pleased, and I was sure he was enjoying making the rest of us try and work out his idea. "It's very easy for you to come down here."

"How, Mac?"

"In a free-fall trajectory. We're in a fifty gee gravity field because we're in a stationary position relative to HC-183. But if you were to let yourself fall in a free orbit, you'd be able to swing in right past us, and away again, and never feel anything but free fall. Agreed?"

"Right. We'd feel tidal effects, but they'd be small." Wenig was calling out displays as he talked, fingers a blur over the computer console. "We can fly right past you, but we'd be there and away in a split second. What could we do in so short a time?"

"Why, what we need." McAndrew sounded surprised by the question. "Just give us a good bang on the side as you go by."

* * *

It sounded easy, as McAndrew so glibly and casually suggested it. When we went into details, there were three problem areas. If we went too close, we'd be fried in the Merganser's drive. Too far off, and we'd never get a strong enough interaction. If all that was worked out correctly, we still had one big obstacle. For the capsule to be freed as Dotterel applied sideways pressure, the drive on the other ship would have to cut off completely. Only for a split.second, but during that time McAndrew and Nina would feel a full fifty gee on them.

That's not quite as bad as it sounds—people have survived instantaneous accelerations of more than a hundred gee in short pulses. But it's not a picnic, either. Mac continued to sound cheerful and casual, mainly for Nina Velez's benefit. But when he listed the preparations that he was taking inside Merganser, I knew he was dealing with a touch-and-go situation.

After all the calculations (performed independently on the two ships, cross-checked and double-checked) we had started our free-fall orbit. It was designed to take us skimming past the Merganser, with a closest separation of less than two hundred meters. We daren't go nearer without risking crippling effects from their drive. We would be flying right through its region of turbulence.

Four hours of discussion between McAndrew and Wenig—with interruptions from Nina and me—had fixed the sequence for the vital half-second when we would be passing the Merganser. The ships would exert gravitational forces on each other, but that was useless for providing the lateral thrust on the life capsule system that McAndrew thought was needed. We had to give a more direct and harder push some other way.

Timing was crucial, and very tricky.

Whatever we threw at the other ship would have to pass through the drive exhaust region before it could impact the life capsule column. If the drive were on, nothing could get through it—at those temperatures any material we had would be vaporized on the way, even if it were there for only a fraction of a second. The sequence had to be: launch mass from Dotterel; just before it got there, kill drive on Merganser; hold drive off just long enough for the Dotterel to clear the area and for the mass to impact the Merganser support column; and back on with their drive, at once, because when the drive was off the Merganser's passengers would be feeling the full fifty gees of the mass plate's gravity.

McAndrew and Wenig cut the time of approach of the two ships into millisecond pieces. They decided exactly how long each phase should last. Then they let the two on-board computers of the ships talk to each other, to make sure that everything was synchronized between them—at the rate things would be happening, there was no way that humans could control them. Not even Wenig, with his super-fast reflexes. We'd all be spectators, while the two computers did the real work and I nursed the abort switch.

There was one argument. McAndrew wanted to use a storage tank as the missile that we would eject from our ship to impact theirs. It would provide high momentum transfer for a very brief period. Wenig argued that we should trade off time against intensity, and use a liquid mass instead of a solid one. Endless discussion and calculations, until Mac was convinced too. We would use all our spare water supply, about a ton and a half of it. That left enough for drinking water on a twenty gee return to the Inner System, but nothing spare for other uses. It would be would be a scratchy and smelly trip home for Dotterel's passengers.

Drive off, we felt only the one-gee pull of our mass plate as we dropped in to close approach. On Merganser, McAndrew and Nina Velez were lying in water bunks, cushioned with everything soft on the ship. We were on an impact course with them, one that would change to a near-miss after we ejected the water ballast. It looked like a suicide mission, running straight into the blue furnace of their drive.

The sequence took place so fast it was anti-climactic. I saw the drive cut off ahead of us and felt the vibration along the support column as our mass driver threw the ballast hard towards Merganser. The brief pulse from our drive that took us clear of them was too quick for me to feel.

We cleared the drive region. Then there seemed to be a wait that lasted for hours. McAndrew and Nina were now in a ship with drive off, dropping towards HC-183. They were exposed to the full fifty gees of their mass plate. Under that force, I knew what happened to the human body. It had not been designed to operate when it suddenly weighed more than four tons. Membranes ruptured, valves burst, veins collapsed. The heart had never evolved to pump blood weighing hundreds of pounds up a gravity hill of fifty gees. The only thing that Mac and Nina had going for them was the natural inertia of matter. If the period of high gee were short enough, the huge accelerations would not have time to produce those shattering physical effects.

Wenig and I watched on our screens for a long, long moment, until the computer on Merganser counted off the last microsecond and switched on the drive again. If the life capsule was free to move along its column, the computer would now begin the slow climb out of HC-183's gravity well. No action was needed from the passengers. When we completed our own orbit we hoped we would see the other ship out at a safe distance, ready for the long trip home.

And on board the ship? I wasn't sure. If the encounter had lasted too long, we might find no more than two limp and broken sacks of blood, tissue and bone.

* * *

It was another long day, waiting until we had been carried around in our orbit and could try to rendezvous the two ships. As soon as we were within radar range, Nina Velez appeared on the com screen. The drive was cut back, so we could get good visual signals. My heart sank when I saw the expression on her face.

"Can you get over to this ship—quickly?" she said.

I could see why all the professors at the Institute had lost their senses. She was small and slight, with a childlike look of trust and sad blue eyes. All a sham, according to everything I'd been told, but there was no way of seeing the strong personality behind the soft looks. I took a deep breath.

"What's happening there?" I said.

"We're back under low gee drive, and that's fine. But I haven't been able to wake him. He's breathing, but there's blood on his lips. He needs a doctor."

"I'm the nearest thing to that in thirty billion miles." I was pulling a suit towards me, sick with a sudden fear. "I've had some medical training as part of the Master's License. And I think I know what's wrong with McAndrew. He lost part of a lung lobe a couple of years ago. If anything's likely to be hemorrhaging, that's it. Dr. Wenig, can you arrange a rendezvous with the mass plates at maximum separation and the drives off?"

"I'll need control of their computer." He was pulling his suit on, too. I didn't want him along, but I might need somebody to return to the Dotterel for medical supplies.

"What should I be doing?" Thank heaven Nina showed no signs of panic. She sounded impatient, with the touch of President Velez in her voice. "I've sat around in this ship for weeks with nothing to do. Now we need action but I daren't take it."

"What field are you in now? What net field?"

"One gee. The drive's off now, and we've got the life capsule right out at the end of the column."

"Right. I want to you stay in that position, but set the drive at one gee acceleration. I want McAndrew in a zero-gee environment to slow the bleeding. Dr. Wenig, can you dictate instructions for that while we are rendezvousing?"

"No problem." He was an irritating devil, but I'd choose him in a crisis. He was doing three things at once, putting on his suit, watching the computer action for the rendezvous, and giving exact and concise instructions to Nina.

Getting ourselves from one ship to the other through open space wasn't as easy as it might sound. We had both ships under one gee acceleration drives, complicated by the combined attraction of the two mass plates. The total field acting on us was small, but we had to be careful not to forget it. If we lost contact with the ships, the nearest landing point was back on Triton Station, thirty billion miles away.

Nina in the flesh was even more impressive than she was over the video link, but I gave her little more than a cursory once-over. McAndrew's color was bad and even while I was cracking my suit open and hustling out of it I could hear a frightening bubbling sound in his breathing. Thank God I had learned how to work in zero gee—required part of any space medicine course. I leaned over him, vaguely aware of the two others intently watching. The robodoc beside me was clucking and flashing busily, muttering a faint complaint at McAndrew's condition and the zero gee working environment. Standard diagnosis conditions called for at least a partial gravity field.

I took the preliminary diagnosis and prepared to act on it while the doc was still making up its mind. Five cc's of cerebral stimulant, five cc's of metabolic depressant, and a reduction in cabin pressure. It should bring Mac up to consciousness if his brain was still in working order. I worried about a cerebral hemorrhage, the quiet and deadly by-product of super-high gees. Ten minutes and I would know one way or the other.

I turned to Wenig and Nina who were still watching the robodoc's silent body trace. "I don't know how he is yet. We may need emergency treatment facilities ready for us as soon as we get back to the System. Can you go over to Dotterel, cut the drive and try to make contact with Triton Station? By the time you have the connection we should have the full diagnosis here."

I watched them leave the ship, saw how carefully Wenig helped Nina to the transfer, and then I heard the first faint noise behind me. It was a sigh, with a little mutter of protest behind it. The most wonderful sound I ever heard in my life. I glanced over at the doc. Concussion—not too bad—and a little more bleeding than I wanted to see from the left lung. Hell, that was nothing. I could patch the lung myself, maybe even start the feedback regeneration for it. I felt a big grin

of delight spreading like a heat wave over my face.

"Take it easy, Mac. You're doing all right, just don't try and rush yourself. We've got lots of time." I secured his left arm so that he couldn't disturb the rib cage on that side.

He groaned. "Doing fine, am I?" He suddenly opened his eyes and stared up at me, "Holy water, Jeanie, that's just like a medic. I'm in agony, and you say it's a little discomfort. How's Nina doing?"

"Not a mark on her. She's not like you, Mac, an old bag of bones. You're getting too old for this sort of crap."

"Where is she?"

"Over on Dotterel, with Wenig. What's the matter, still infatuated?"

He managed a faint smile. "Ah, none of that now. We were stuck on Merganser for more than two weeks, locked up in a three meter living sphere. Show me an infatuation, and I'll show you a cure for it."

The com link behind me was buzzing. I cut it in, so that we could see Wenig's worried face.

"All right here," I said, before he had time to worry any more. "We'll be able to take our time going back. How are you? Got enough water?"

He nodded. "I took some of your reserve supply to make up for what we threw at you. What should we do now?"

"Head on back. Tell Nina that Mac's all right, and say we'll see you both back at the Institute."

He nodded again, then leaned closer to the screen and spoke with a curious intensity. "We don't want to run the risk of having a stuck life capsule again. I'd better keep us down to less than ten gee acceleration."

He cut off communication, without another word. I turned to McAndrew. "How high an acceleration before you'd run into trouble with these ships?"

He was staring at the blank screen, a confused look on his thin face. "At least forty gee. What the devil's got into Wenig? And what are you laughing at, you silly bitch?"

I came over to him and took his right hand in mine. "To each his own, Mac. I wondered why Wenig was so keen to get here. He wants his shot at Nina—out here, where nobody else can compete. What did you tell her—some sweet talk about her lovely eyes?"

He closed his eyes again and smiled a secret smile. "Ah, come on Jeanie. Are you telling me you've been on your best behavior since I last saw you? Gi' me a bit of peace. I'm not soft on Nina now."

"I'll see." I went across to the drive and moved us up to forty gee. "Wait until the crew on Titan hear about all this. You'll lose your reputation."

He sighed. "All right, I'll play the game. What's the price of silence?"

"How long would it take a ship like this to get out to Alpha Centauri?"

"You'd not want this one. We'll have the next one up to a hundred gee. Forty-four ship days would get you there, standing start to standing finish."

I nodded, came back to his side and held his hand again. "All right, Mac, that's my price. I want one of the tickets."

He groaned again, just a bit. But I knew from the dose the doc had put into him that it wasn't a headache this time.


Title: The Compleat McAndrews
Author: Charles Sheffield
ISBN: 0-671-57857-X
Copyright: © 2000 by Charles Sheffield
Publisher: Baen Books