Lucky Starr The And The Moons of Jupiter ls-5

by Isaac Asimov

  "But the men aboard ship have been chosen long since."

  "The Sirians would know the reasons for choosing and the method of choice just as they know everything else about the project and they would maneuver their humanoid robot so as to have him chosen."

  "That's giving them a lot of credit," muttered Panner.

  "I admit it," said Lucky. "There is an alternative."

  "Which is?"

  "That the humanoid robot is aboard as a stowaway."

  "Very unlikely," said Panner.

  "But quite possible. It might easily have boarded the ship in the confusion before the commander made his christening speech. I tried to watch the ship then, but it was impossible. Furthermore, nine tenths of the ship seems to be made up of engine compartment, so there must be plenty of room to hide."

  Panner thought about it. "Not as much room as you might think."

  "Still we must search the ship. Will you do that, Dr. Panner?"

  "I?"

  "Certainly. As chief engineer, you would know the contents of the engine compartment better than anyone else. We'll go with you."

  "Wait. It's a fool's errand."

  "If there is no stowaway, Dr. Panner, we have still gained something. We'll know we can restrict our consideration to the men legally aboard ship."

  "Just three of us?"

  Lucky said quietly, "Whom can we trust to help us, when anyone we might ask might be the robot we're looking for? Let us not discuss this any further, Dr. Panner. Are you willing to help us search the ship? I am asking your help in my capacity as a member of the Council of Science."

  Reluctantly Panner got to his feet. "I suppose I must then."

  They clambered down the hand holds of the narrow shaft leading to the first engine level. The light was subdued and, naturally, indirect, so that the huge structures on either side cast no shadow.

  There was no sound, no slightest hum to indicate activity or to show that vast forces were being trapped and dealt with. Bigman, looking about, was appalled to find that nothing seemed familiar; that of the ordinary workings of a space ship, such as that of their own Shooting Starr, nothing seemed left.

  "Everything's closed in," he said.

  Panner nodded and said in a low voice, "Everything is as automatic as possible. The need for human intervention has been cut to the minimum."

  "What about repairs?"

  "There shouldn't have to be any," the engineer said grimly. "We have alternate circuits and duplicated equipment at every step, all allowing for automatic cut-in after self-check."

  Panner moved ahead, guiding them through the narrow openings but moving always slowly as though at any moment he expected someone, or some thing, to hurl itself murderously upon them.

  Level by level, methodically moving out from the central shaft along the side channels, Panner probed each bit of room with the sureness of the expert.

  Eventually they came to a halt at the very bottom, hard against the large tail jets through which the glowing hyperatomic forces (when the ship was in ordinary flight) pressed backward to push the ship forward.

  From within the ship the test jets showed as four smooth pipes, each twice as thick as a man, burrowing into the ship and ending in the tremendous featureless structures that housed the hyperatomic motors.

  Bigman, said, "Hey, the jets! Inside!"

  "No," said Panner.

  "Why not? A robot could hide there fine. It's open space, but what's that to a robot?"

  "Hyperatomic thrusts," said Lucky, "would be plenty to it and there've been a number of those till an hour ago. No, the jets are out."

  "Well, then," said Panner, "there's no one anywhere in the engine compartments. No thing, either."

  "You're sure?"

  "Yes. There isn't a place we haven't looked, and the route I followed made it impossible for anything to get around and behind us."

  Their voices made small echoes in the lengths of shafts behind them.

  Bigman said, "Sands of Mars, that leaves us with the fourteen regulars."

  Lucky said thoughtfully, "Less than that. Three of the men aboard ship showed emotion: Commander Donahue, Harry Norrich, Red Summers. That leaves eleven."

  Panner said, "Don't forget me. I disobeyed an order. That leaves ten."

  "That raises an interesting point," said Lucky. "Do you know anything about robotics?"

  "I?" said Panner. "Never dealt with a robot in my life."

  "Exactly," said Lucky. "Earthmen invented the positronic robot and developed most of the refinements, yet, except for a few specialists, the Earth technician knows nothing about robotics, simply because we don't use robots to any extent. It isn't taught in the schools and it doesn't come up in practice. I myself know the Three Laws and not too much more. Commander Donahue couldn't even quote the Three Laws. The Sirians, on the other hand, with a robot-saturated economy, must be past masters at all the subtleties of robotics.

  "Now I spent a good deal of time yesterday and today with a book-film on advanced robotics, that I found in the project library. It was the only book on the subject, by the way."

  "So?" said Panner.

  "It became obvious to me that the Three Laws aren't as simple as one might think… Let us move on, by the way. We can give the engine levels a double check on the way back." He was moving across this lowest level as he spoke, looking with keen interest at his surroundings.

  Lucky continued, "For instance, I might think it would only be necessary to give each man on the ship a ridiculous order and note whether it be obeyed. As a matter of fact, I did think so. But that isn't necessarily true. It is theoretically possible to adjust the positronic brain of a robot to obey only those orders that belong naturally to the line of its duties. Orders that are contrary to those duties or irrelevant to them may still be obeyed provided that they are preceded by certain words which act as a code or by the person who gives the orders identifying himself in a certain way. In this manner a robot can be handled in all ways by its proper overseers and yet be insensitive to strangers."

  Panner, who had placed his hands on the holds that would guide the men up to the next higher level, released them. He turned to face Lucky.

  He said, "You mean when you told me to take off my shirt and I didn't obey, that meant nothing?"

  "I say it could have meant nothing, Dr. Panner, since taking off your shirt at that moment was no part of your regular duties, and my order might not have been stated in the proper form."

  "Then you're accusing me of being a robot?"

  "No. It isn't likely that you are. The Sirians, in choosing some member of the project to replace by a robot, would scarcely choose the chief engineer. For the robot to do that job properly, it would have to know so much about Agrav that the Sirians couldn't supply the knowledge. Or, if they could, they would have no need to spy."

  "Thanks," said Panner, sourly, turning toward the hand holds again, but now Bigman's voice rang out.

  "Hold it, Panner!" The small Martian had his ready needle-gun in his fist. He said, "Wait a minute, Lucky, how do we know he knows anything about Agrav? We're just assuming that. He never showed us any knowledge. When the Jovian Moon shifted to Agrav, where was he? Sitting on his squatter in his quarters with us, that's where he was."

  Lucky said, "I thought of that, too, Bigman, and that's one reason I brought Panner down here. He's obviously acquainted with the engines. I've watched him inspect everything and he couldn't have done it with such assurance if he weren't an expert on the workings."

  "Does that suit you, Martian?" Panner demanded with suppressed anger.

  Bigman put his needle-gun away, and without a further word Panner scrambled up the ladder.

  They stopped off at the next level, working through it a second time.

  Panner said, "All right, that leaves ten men: two army officers, four engineers, four workmen. What dp you propose to do? X-ray each of them separately? Something like that?"

  Lucky shook his head. "That's too risk
y. Apparently the Sirians have been known to use a cute little trick to protect themselves. They've been known to use robots to carry messages or to perform tasks which the individual giving the orders wanted to be kept secret. Now obviously a robot can't keep a secret if a human being asks him, in the proper fashion, to reveal it. What the Sirians do, then, is to install an explosive device in the robot which is triggered by any attempt to force the robot to give away the secret."

  "You mean if you put an X-ray on the robot, it will explode?"

  "There's a very good chance that it would. Its greatest secret is its identity, and it may be triggered for every attempt to discover that identity that the Sirians could think of." Lucky added regretfully, "They hadn't counted on a V-frog; there was no trigger against that. They had to order the robot to kill the V-frog directly. Or that might have been preferable anyway, since it managed to keep the robot alive undetected."

  "Wouldn't the robot be harming humans nearby if it exploded? Wouldn't it be breaking First Law?" asked Panner with a trace of sarcasm.

  "It wouldn't. It would have no control over the explosion. The triggering would be the result of the sound of a certain question or the sight of a certain action, not the result of anything the robot itself would do."

  They crawled up to still another level.

  "Then what do you expect to do, Councilman?" demanded Panner.

  "I don't know," Lucky said frankly. "The robot must be made to give itself away somehow. The Three Laws, however modified and fancified, must apply. It's only a question of being sufficiently acquainted with robotics to know how to take advantage of those Laws. If I knew how to force the robot into some action that would show it to be non-human without activating any explosive device with which it might be equipped; if I could manipulate the Three Laws so as to force one to conflict with another sufficiently strongly to paralyze the creature completely; if I-"

  Panner broke in impatiently, "Well, if you expect help from me, Councilman, it's no use. I've told you already I know nothing of robotics." He whirled suddenly. "What's that?"

  Bigman looked about, too. "I didn't hear anything."

  Wordlessly Panner squeezed past them, dwarfed by the bending metal tube on either side.

  He had gone almost as far as he could, the other two following, when he muttered, "Someone might have squeezed in among the rectifiers. Let me pass again."

  Lucky stared, frowning, into what was almost a forest of twisting cables that enclosed them in a complete dead end.

  Lucky said, "It seems clear to me."

  "We can test it for sure," Panner said tightly. He had opened a panel in the wall nearby and now he reached in cautiously, looking over his shoulder.

  "Don't move," he said.

  Bigman said testily, "Nothing's happened. There's nothing there."

  Panner relaxed. "I know it. I asked you not to move because I didn't want to slice an arm off when I established the force field."

  "What force field?"

  "I've shorted a force field right across the corridor. You can't move out of there any more than you could if you were encased in solid steel three feet thick."

  Bigman yelled, "Sands of Mars, Lucky, he is the robot!" His hand lunged.

  Panner cried at once, "Don't try the needle-gun. Kill me and how do you ever get out?" He stared at them, dark eyes sparking, his broad shoulders hunched. "Remember, energy can get through a force field but matter can't, not even air molecules. You're airtight in there. Kill me and you'll suffocate long before anyone happens to come across you down here."

  "I said he was the robot," said Bigman in raging despair.

  Panner laughed shortly, "You're wrong. I'm not a robot. But if there is one, I know who it is."

  11. Down the Line of Moons

  "Who?" Bigman demanded at once.

  But it was Lucky who answered. "Obviously he thinks it's one of us."

  "Thanks!" said Panner. "How would you explain it? You mentioned stowaways; you talked about people forcing their way on board the Jovian Moon. Talk about nerve! Aren't there two people who did force their way on board? Didn't I witness the process? You two!"

  "True enough," said Lucky.

  "And you brought me down here so you could investigate every inch of the ship's workings. You tried to keep me busy with stories about robots hoping I wouldn't notice that you two were going over the whole ship with a microscope."

  Bigman said, "We have a right to do it. This is Lucky Starr!"

  "He says he's Lucky Starr. If he's a member of the Council of Science, he can prove it and he knows how. If I had any brains, I'd have demanded identification before taking you down."

  "It's not too late now," Lucky said calmly. "Can you see clearly from that distance?" He held up one arm, palm forward, and peeled the sleeve back.

  "I'm not coming any closer," Panner said angrily.

  Lucky said nothing to that. He let his wrist tell the story. The skin along the inner surface of his wrist seemed merely exposed skin, but years before it had been treated hormonally in a most complicated fashion. Responding to nothing more than a disciplined effort of Lucky's will, an oval spot on the wrist darkened and slowly turned black. Within it, little yellow specks formed in the familiar patterns of the Big Dipper and of Orion.

  Panner gasped as though the breath had been forcibly knocked out of his lungs. Few human beings had the occasion to see this sign of the Council, but all above the age of childhood knew it for what it was- the final and unforgeable identification insigne of the councilman of science.

  Panner was left with no choice. Silently, reluctantly, he released the force field and stepped back.

  Bigman came out, raging, "I ought to bend in your skull, you lopsided-"

  Lucky pulled him back. "Forget it, Bigman. The man had as much right to suspect us as we had to suspect him. Settle down."

  Panner shrugged. "It seemed logical."

  "I admit it did. I think we can trust each other now."

  "You, maybe," the chief engineer said pointedly. "You're identified. What about this little loudmouth with you? Who identifies him?"

  Bigman squawked incoherently and Lucky stepped in between the two. "I identify him and take full responsibility for him… Now I propose that we get back to passenger quarters before a search is organized for us. Everything that went on down here is, of course, strictly confidential."

  Then, as though nothing had happened, they resumed the climb upward.

  The room assigned to them contained a two-decker bed and a washstand out of which a small trickle of water could be urged. Nothing more. Even the cramped and Spartan quarters on board the Shooting Starr were luxury to this.

  Bigman sat cross-legged on the upper bed, while Lucky sponged his neck and shoulders. They talked in whispers, conscious of the listening ears that might be present on the other side of the walls.

  Bigman said, "Look, Lucky, suppose I go up to each person on board ship; I mean, each of the ten we don't know about? Suppose I deliberately pick a fight with each one, call them a few names, things like that? Wouldn't it turn out that the guy who doesn't take a punch at me is the robot?"

  "Not at all. He might not want to break shipboard discipline, or he might know what a handy fellow you are with a needle-gun, or he might not want to get into a wrangle with the Council of Science, or he might Just not like to hit a man smaller than himself."

  "Aw, come on, Lucky." Bigman was silent for a minute, then he said cautiously, ''I've been thinking; how can you be sure the robot is aboard ship? I keep thinking maybe it stayed back on Jupiter Nine. It's possible."

  "I know it's possible and yet I'm sure the robot is here on board ship. That's just it. Fm sure and I don't know why I'm sure," said Lucky, his eyes dark with thought. He leaned against the bed and tapped his teeth with the knuckle of one finger. "That first day we landed on Jupiter Nine, something happened."

  "What?"

  "If I only knew! I had it; I knew what it was, or thought I did, just be
fore I went to sleep that night, and it vanished. I haven't been able to get it back. If I were on Earth, I'd submit to a psycho-probe. Great Galaxy, I swear I would!

  ''I've tried every trick I could. Thinking hard, getting my mind off it altogether. When we were with Panner down in the engine levels, I tried talking my fool head off. I thought if I would just keep discussing every aspect of the matter, the thought was bound to pop into my head. It didn't.

  "But it's there just the same. It's because of the thought that I must feel so sure the robot is one of the men aboard ship. I've made the subconscious deduction. If I could only put my finger on it, I'd have the whole answer. If I could only put my finger on it"

  He sounded almost despairing.

  Bigman had never seen Lucky with quite that look of frustrated loss in his face. He said, worried, "Hey, we'd better get some sleep."

  "Yes, we'd better."

  Minutes later, in the darkness, Bigman whispered, "Hey, Lucky, what makes you so sure I'm not the robot myself?"

  Lucky whispered back, "Because the Sirians couldn't bear to build a robot with such an ugly face," and lifted his elbow to ward off a flying pillow.

  The days passed. Halfway to Jupiter, they passed the inner and more sparsely populated belt of small moons, of which only Six, Seven, and Ten were numbered. Jupiter Seven was visible as a bright star, but the others were far enough away to melt into the background of the constellations.

  Jupiter itself had grown to the size of the moon as seen from Earth. And because the ship was approaching the planet with the sun squarely to its rear, Jupiter remained in the "full" phase. Its entire visible surface was ablaze with sunlight. There was no shadow of night advancing across it.

  Yet though the size of the moon, it was not so bright as the moon by any means. Its cloud-decked surface reflected eight times as much of the light that reached it, as did the bare powdered rock of the moon. The trouble was that Jupiter only received one twenty-seventh of the light per square mile that the moon did. The result was that it was only one third as bright at that moment as the moon appeared to be to human beings on Earth.