The Murder of Halley’s Comet by Larry Niven and David Drake

Even with half a square kilometer of light-sail deployed, the Khalian projectile was an insignificant blip compared to the four-kilometer diameter of the comet’s core. The entire unit weighed just under ten kilograms. There was a terminal-guidance system which incorporated a proximity fuse, a small bursting charge, a reflective shell, and tiny servomotors coupled to the spars of the light-sail.

The sail blazed with a terrible intensity, a tiny, peculiar star, brilliant green. It was traveling at almost 25,000 kilometers per second8 percent of light speedwhen the payload detonated. The cloud of shrapnel grew but continued with the same course and velocity as the missile had before exploding.

Its target was black with age, invisible against the sky.

The projectile had become a cloud over four kilometers across when it splashed across the ancient ice ball. Traveling at a significant fraction of light speed, the shrapnel’s effect was that of a blast of gamma rays. Half of the comet’s surface absorbed the impact and vaporized instantly. Stresses transmitted by flash heating shattered the remnant of the loosely compacted ball of snow and slag.

The comet exploded. Thirty-meter chunks of rock and finger-sized shards of ice drifted apart in millions of separate orbits.

The Admiral Wilhelm Canaris hadn’t moved in nearly a decade. The huge spiky cylinder rested in unstable equilibrium in the L3 point of the Earth-Moon system, at the fringes of Earth’s gravity field. Escape craft were positioned to serve as attitude jets. Their main motors fired now and then to adjust the big vessel’s orbit.

The heart of the Willy C wasn’t the vessel’s bridge, but rather the office deep in its interior where sat Sector Commander Lars Eriksen, the Fleet’s highest ranking officer for thirty light years in any direction. The bridge only controlled the vessel’s rare course adjustments: trivial matters to a sector commander.

A sector commander’s business was politics.

The spymaster-class command and control ship circled Earth itself, where the Alliance Senate met and deliberated on the Fleet’s budget. In an hour Eriksen would be meeting the Senate’s Trade and Industry Committee. Deep inside several concentric metal shells within what could still be described as a tremendous warship, Eriksen sat within a ring of heads. He was choosing among the alternative hairstyles that his coiffeur had downloaded into his hologram projector.

Two of the three doors into his office burst open simultaneously. Eriksen looked up. So did six bodiless heads, each slightly different yet each his own, all rotating, all annoyed.

“Our telemetry links” blurted Captain Crocker, head of the sector’s Bureau of Military Affairs.

“On the omni” said Captain Krasnowski, head of the sector’s Bureau of Civil Affairs as he pointed to the omni unit beside the desk.

The captains were too agitated to notice one another’s presence. The admiral gestured with his little finger; his desk’s artificial intelligence shut off the omni hologram projector. The other heads faded.

“on Halley’s comet” continued Crocker.

“Noel Li says” continued Krasnowski.

“report that the comet has exploded!”

“that the Khalians have blown up Halley’s comet! Oh, sorry, Grig.”

Eriksen pointed to the omni and said, “On.”

The AI responded instantly to Eriksen’s command. The omni’s surface clothed itself in a three-dimensional image that appeared to squarely face every human in the room. Noel Li, Earth’s top newsreader, was saying, “however, Fleet sources have refused to comment”

Somebody from Technical Affairs chimed for admittance at the third door to Eriksen’s office.

“Come!” the admiral snarled, his eyes on Noel Li.

“on whether the comet’s destruction was the first action of a Khalian armada headed for Earth.”

Halley’s had been visible when Eriksen’s eldest son Mark was born; so his wife had told him. Thirty-four years ago. The comet must be almost at aphelion, near Neptune’s orbit, Eriksen thought; better check when he had the chance.

Li’s face was replaced by an image of what Eriksen took to be Halley’s comet. The holocast showed it as a cold gray ball, dimly lit, lumpy. Steam feathered out from some surface crack. Above the image glowed the word simulationin English, because the men in the office had been speaking English.

Simulation. The real Halley’s was black with comet tar, carbon and polymers and other solids left on the surface by evaporating ice. The astronauts had to wear Teflon boots. Water volcanoes peaked all around them, and tiny Jupiter rose every seven hours twenty-four minutes. Thirty-five years ago, when Mark was conceived, they’d left the omni on for the whole four days, with the Halley’s expedition as background.

One side of the dark sphere suddenly glared flame-green. A moment later a bright cap of vapor exploded away from almost a third of the original surface. The dark side shattered, a snowball striking a wall. Ice fragments spewed one way, steam the other.

I’m watching computer-programmed guesswork. The map is not the territory. Simulation … but Halley’s comet is dead.

“Ah, that’s what it was,” said Commander Mown, who’d entered the third door when the AI opened it. Unlike Crocker and Krasnowski, the head of Technical Affairs didn’t have even the option of barging in on the sector commander unannounced. “Just a drive laserso of course the modulation was random.”

“What?” said Admiral Eriksen, twisting to look squarely at the ferally slender Mown.

“Whatwhat?” gabbled Crocker and Krasnowski.

“Do you mean you” Eriksen began.

“Is this something” said Crocker.

“How do you mean” said Krasnowski.

Eriksen turned again and stared at his Civil and Military Affairs chiefs. They were not too flustered by the situation to read danger in the admiral’s look.

In the silence, Commander Mown said, “Three days ago, a courier on the Earth-Titan run, the Sabot, I believe, with three crew named”

“Mown.”

“Yes, of course, sir. The Sabot encountered what appeared to be a powerful laser signal directed inward, across the solar ecliptic. They recorded the dataas a matter of courseand passed them on to us for analysis.”

As Mown talked, he tapped the side of the multifunction helmet he wore even here in his superior’s office. His eyes focused on the holographic display it projectedvisible to the others in the room only as occasional flickersand his fingers tapped a rapid pattern of keystrokes in the air. The nerve impulses rather than the “touch” of Mown’s fingertips controlled the data flow.

“We assumed it was a message. It was modulated. We found coded patches in Old French and English and Japanese. We wondered if the code was changing second by second. Truth was, there was nothing to analyze,” Mown’s voice continued while his eyes tracked information the others couldn’t see. “We think the modulations are partly randomized and partly bits of old messages in obsolete codes, stuff the Khalians must have been picking up for a century. The beam’s only a drive laser of considerable

“Here we are. Yes, quite correct. The vector indicates that it was driving a projectile toward Halley’s comet.”

Mown’s fingers danced as though he were executing half of a secret handshake for entry to a lodge. The data terminal opposite the omni obliged: it switched itself on to project visions.

Admiral Eriksen watched a schematic of the solar system from behind the omni. Here was black space where reality held only his office wall. Planetary orbits showed in primary colors, each a ring with a cluster of lumps on it, wound tight around the white dot of the sun. Thousands of spacecraft showed as little vector arrows. Clusters of comets showed as clouds. A bright green path indicated the computed track of the laser beam.

Fury closed Eriksen’s throat. Halley’s comet! Without the capacity for berserk rage, he never would have survived his two decades as a warrior. He’d learned how to swallow rage. But: A thousand years ago, Halley’s comet showed us that we can predict. There is more than caprice in the world; there is law. The Weasels have murdered law.

“listeners fully informed about the crisis,” Noel Li’s image closed primly.

“Off!” snapped Eriksen, pointing a finger toward the omni and wishing he had a pistol. He pointed at Mown and said, “Commander, stand in front of me where I can see you without pretending to be a contortionist!”

The admiral’s tone cut through the hazy reality that surrounded the Technical Affairs chief. He hopped quickly around Eriksen’s desk to stand between Crocker and Krasnowski.

Eriksen pointed to the green track of the enemy laser beam. It wasn’t a line, it was a narrow fan of probable paths. “Why the blurring? Where’s the uncertainty?”

Mown answered, “We don’t know very much about the projectile, after all. We can guess how hard it hit, that is, how much kinetic energy it was carrying. We’ve seen the beam, so we know how much energy was in that. But we don’t know the mass of the bullet, or the size of the light-sail, or how long the beam was on”

A pair of panicked lieutenant commanders, the seconds in command of both Military and Civil Affairs, burst into Eriksen’s office behind their chiefs.

“Sir!” blurted the officer from Military Affairs. It was unclearperhaps even to herwhether she was speaking to her direct superior or to Eriksen himself. “The secretary of the Senate Liaison office just called. He’s demanding we sound Red Alert and recall at least three battle squadrons soonest!”

“Sir!” said the junior from Civil Affairs, to Krasnowski. “The president of the Senate’s on the line for”his eyes flicked toward the admiral”Admiral Eriksen. The president herself is on the line!”

Eriksen’s handsome features were a requisite for his position, but there was nothing wrong with his mind, or his ability to act with decision. He pointed toward Krasnowski. “All right,” he said. “I’ll take President Ssrounish’s call.”

His finger twitched toward Crocker. He said, “Red Alert. Do it.”

“And the recall?” piped Crocker’s aide.

“I said alert! If I meant something else” Keep it simple, especially when giving important orders. Keep it explicit, keep it simple. “Do not send a recall. I have not authorized a recall.”

Noddingboth lieutenant commanders white-facedall the intruders started to leave Eriksen’s office. “Wait,” the admiral ordered crisply.

He pointed toward Mown. “You,” he said. “Can you locate the source of that drive laser?”

Commander Mown’s lips pursed. “Very probably, yes,” he said. “Yes, I suppose so.”

“Make the attempt,” Eriksen said. “And you”Crocker snapped to attention, at the business end of the admiral’s finger”take his plot, and if it is Weasels, I want their ears! Dismissed!”

The office cleared. Crocker followed Mown. As they disappeared into the corridor leading to Technical Affairs, Mown was saying, “Actually, Khalians have very small external ears. It’s my understanding that the field units take the tails as …”

“Why was I not informed of thisss … ?” demanded President Ssrounish. Her accent was normally flawless; she drew out the terminal ess of her question now to have an excuse to curl her lip above her fangs. “Why was no member of the Ssenate informed?”

The Alliance of Planets was denounced often enoughand with enough truthas the Alliance of Human Planets. It may be worth noting that such denunciations came generally from humans and Hrrubans. Other species did not find it worthy of comment that a powerful race should favor its own.

But when a thoroughly acceptable nonhuman candidate presented herself for the post of president of the Alliance Senate, her colleagues had voted her in by an overwhelming margin. The duties of president were largely those of a figurehead

And the head of Madame Ssrounish, the Hrruban senator, was fearfully impressive.

Ssrounish was intelligent by any standards, much less those of politicians. Her grace and beauty were remarkable; and in her social dealings she had invariably proved herself to be as gentle as a butterfly. Nevertheless, as Admiral Eriksen faced the holographic image of the catlike Hrruban, his insides twisted the way those of his remote ancestors had done when a saber-tooth stalked through the entrance of their cave.

“Madame President,” Eriksen said with the dignity of absolute truth, “I believe you learned as fast as I did. I’ve just watched it on the omni. That is all I or my chief aides know about the event.”

“What?” Ssrounish’s jaws twitched as though she were trying to swallow a bolus too large for her throat. It was simply a gesture, but Eriksen’s instincts told him to hurl himself through the doorway behind him.

“Halley’s comet has exploded,” he said calmly. “We know that much. We’ll know more shortly.”

Eriksen had commanded the Tegetthoff when plasma bolts killed fifty-eight of the seventy men with him on the cruiser’s bridge. This wasn’t the first time he’d had to function when he was scared green.

Ssrounish blinked but remained silent for a moment. “I don’t” she began. Then her eyes clicked into focus again, and she continued decisively, “What additional measures are you taking to safeguard Earth, Admiral?”

Superimposed over Ssrounish’s image in the holovision tank were red letters reading senator penrythanother priority call that Eriksen’s aides knew their chief would have to deal with personally. Hugh David Penryth’s votes were so closely identified with policies emanating from Fleet headquarters on Tau Ceti that he was knownnot to his faceas the Senator From Tau Ceti.

Penryth would be asking the same questions as Ssrounish, but his priorities would differ. Eriksen thought vaguely of merging the calls, but this was going to be unpleasant enough one-on-one.

“Earth’s defensesthe Home System defenses” Eriksen said, “are already sufficient to meet any potential threat, Madame President. Until”

“You say that, wrapped in a Fleet dreadnought!” Ssrounish roared. She reared up on her hind legs; the sending unit in her holotank panned back automatically to show the august president of the Alliance Senate clawing strips from the three-meter ceiling of her office. “The Meeting Hall has nothing above it but cloudsand they are sparse enough in this damned bright atmosphere!”

Must I step outside to speak further? These days Eriksen rarely exercised his talent for sarcasm. “Madame President, the Home System is more heavily defended”

“I am old and perhaps ready to die!” Ssrounish continued, belying her words with the supple fury of her limbs. “But my colleaguesthe senators who vote the Fleet’s appropriationsthey are perhaps not all so philosophical!”

But enough was enough. “One may hope they are less timid, also,” Eriksen said. “Sol system is more heavily defended than Port Tau Ceti. Any monkey with a spacecraft can blow a snowball apart, but a real Khalian attack would require greater force than they’ve ever demonstrated … if the Khalians are even involved. We have only the news broadcasts to suggest even that.”

“You said ‘timid,’ ” President Ssrounish said.

“Have you remembered your dignity, Madame President?”

President Ssrounish settled back into her normal posture, bonelessly, like a house cat. “Admiral, you must be very sure of yourself.”

“Why not? This is my skill.”

“You say that we have only the omni newscasts to thank for any information about the attack. How is it that Noel Li knew about it before you did? … or the Senate either!”

“Madame President,” said Eriksen grimly, “I hope to find you an answer very soon.”

When Lieutenant Scarlatti’s console began making busy chuckling sounds, Scarlatti stood, stretched, then leaned over the divider to see how Lieutenant Stich was doing.

Stich was rising also, sweeping her fingers across her scalp as if to straighten the hair that she’d had stylishly removed. Almost no one really looked good as a baldie, but Jenna Stich was the “almost.”

“What do they have you on, Alec?” she asked Scarlatti with a smile that sometimes made him wonder what a female praying mantis looked like to a male. Beautiful. Worth whatever it took …

“Ah!” he said, snapping back to the reality of the two of them on duty, ten levels deep inside the Willy C.

Of course, their consoles were doing the real work.

Still.

“One of the courier ships tracked through a laser. Somebody’s drive laser,” Scarlatti explained, glancing back at his console to be sure that it didn’t require a human decision. Nope. “I’m to calculate the probable track of the laser and come up with a source … assuming it was ship-mounted. Max priority.”

Stich frowned and said, “But you can’t calculate direction from one point, can you?”

“Well, no, but it’s not a point.” Scarlatti gestured to his console and muttered a command. Stich moved closer to see over the divider; their arms were almost touching. “The courier was in the beam for almost thirty seconds, so there’s a good long line to work with.”

The ignorance implied by Stich’s question bothered him for a moment; it was as though she’d asked him how to turn on her console. But though the units were identical, the operators and their jobs were not. Jenna didn’t do the particular sort of number crunching that was second nature to Scarlatti.

The console obediently gave him visuals, a green line hanging in the air. “The intersection line,” he explained. The green shrank to a mere dash, then extended in orange from one end, in a narrow flattened cone that stretched to the limit of the hologram display. “And a location cone, depending on the sender’s course and speed. I’m checking the extension against known objects before I run a plot from what I have already.”

Scarlatti knew that what he had so far wasn’t enough to locate the sender, unless a couple of battle squadrons were recalled to the Home System to sift through all the possibilities; but Stich probably didn’t realize that. The bit of harmless boasting made the young lieutenant feel good.

Beaming with his promise of success, Scarlatti said, “What do they have you on, ah, Jenna? Not”a cloud passed over the sun of Scarlatti’s hopes”a cross-check on my, ah”

“Oh, no, nothing like that!” Lieutenant Stich warbled in amusement. “One of the omni newsreaders announced”

Stich cued her console with a gesture Scarlatti failed to catch. The unit said in Noel Li’s dulcet, cultured tones, “… the Khalians have blown up …”

“Halley’s comet blew up before anybody here knew about it,” Stich continued over the newsreader’s voice. “I’m looking for the source of their data”

“… Fleet sources have refused comment on …”

“What?” Scarlatti interjected, pointing as though the recorded words weren’t utterly disembodied. “You mean they did report it to us before the broadcast and somebody”

Stich’s smile wasn’t so much mechanical as electronic in its precision. She gestured again. Li’s voice switched in midsyllable to a man saying, “… Landhope, producer of the Morning News. We have a report”

“Assistant producer,” murmured Stich coldly. “He’s calling Commander Brujilla in the Public Information office thirteen minutes before air time.”

“just been blown up by a Khalian armada incoming to attack Earth. Can you comment on that for the record, Commander?”

“What?” demanded a female voice from the heart of Stich’s console. “Landhope, what are you on?”

“Commander Brujilla, I’m not going to be put off by pretended ignorance,” the producer snapped. “If the Fleet refuses comment on the biggest security lapse since Pearl Harbor, we’ll run what we’ve got!”

“Well, run it and be damned, then, Landhope! And if you think your calls here’ll ever be answered again, y”

“Ooh …” said Scarlatti.

“Yeah,” said Stich. “Brujilla’s got about as much chance of promotion as Ito van Pool.” Van Pool had docked Admiral Ozul’s gig three meters deep into his flagship’s hull, sixty years ago. Such things are remembered. “And I’d have said the same thing if anybody’d called me with such an idiot story …”

“Sure, anybody would,” Scarlatti agreed. The cold feeling in the pit of his stomach had crushed all the pride, all the sexual display, out of his voice. He’d just seen somebody’s career get hit by an astrobleme.

Stich gestured again. “This is the call to Broadcast Towers,” she said.

“How do you … ?” Scarlatti asked. “I mean, are you just pulling these calls out of a file, or … ?”

“Of course,” Stich agreed. Her quizzical expression reminded Scarlatti of how he’d felt when she asked a ridiculous question about course computation. “They don’t name these ships after spymasters and hang them over sector capitals for nothing, Alec. I told my console to sort message traffic to and from Broadcast Towers over the past three days, using the key phrase ‘Halley’s comet.’ “

“… Towers,” said a voice from the console. “Can I help you, please?”

“Record this,” responded another voice, probably unnecessarily. “I won’t say it again. A”

“We don’t have a match on the voice, at least yet,” Stich explained in an undertone, “but the call originated from Dallas.”

“Khalian armada is inbound toward Earth. They have already destroyed Halley’s comet. Professor Sitatunga at Fermi-Geneva will confirm this.”

“Thirty-seven minutes before air time,” Stich added with professional appreciation. “They were cutting it close.”

When Jenna Stich flicked her control hand again, the console generated a hologram of a man with implanted haira cheap job that looked as though the surgeon normally specialized in putting greensoriental features, and a rich black complexion.

“Yes, yes?” a voice was saying; the image’s lips moved, slightly out of synch with the words. “I am Sitatunga, yes.”

Noticing Scarlatti’s frown, Stich said, “They didn’t have enough warning to arrange pictures for the initial flash, but they got cameras on him later. I’m just manipulating those sends to fit the initial call.”

“… told me you’d be calling about my research …”

“Told by the same guy as made the call to the station?”

Stich nodded absently.

“Yes, Professor, but what about the comet exploding?” The caller from Broadcast Towers was probably Landhope; Scarlatti couldn’t tell.

Stich murmured, “Yes, he called Sitatunga from Dallas the day before, pretending to be Noel Li’s producer himself.”

The holographic face registered amazement and horror. “Why are you saying this to me? This is no joke! The comet is not exploded, it”

“Told him they wanted a feature on Halley’s comet, so he’d have the latest telemetry ready when the station called”

“See, right here!” insisted Sitatunga, obviously pointing to a display terminal that would probably have been illegible even if he were on-camera during the conversation. “It says … oh my God! Oh my God! Oh my God!”

“Professor?”

“All my equipment! Gone! Gone! Exploded as you say! All my life!”

Stich gestured away the scientist’s voice and the sight of his pop-eyed horror.

“He was the greatest authority on the comet in … I suppose the universe,” she explained. Her mouth moved in what could have been a cold smile. “I suppose he still is, but there isn’t as much now to know.”

“Except who did it. And even that” A pulse of red light and the beep in Scarlatti’s mastoid implant warned him that his console needed a human decision.

“Go ahead,” he ordered as he turned to face his equipment.

confirmation points appeared in the air in bright amber letters. The heading lifted a hand’s breadth. Beneath itin red, indicating a high degree of probabilityappeared mars, followed by thirty-digit time-location parameters.

“Right,” Scarlatti said. “Check it out.”

Stich waited a decent five seconds to be sure she wouldn’t interrupt further business, then asked, “Check what out?”

“Ah,” said Scarlatti. “The calculated course suggests the drive beam may have intersected Mars before it hit the Sabot.”

“Wouldn’t that have been reported?”

“Sure,” Scarlatti agreed, “but so what? A laser beam intersecting a Fleet unit is an incident that sets off alarms. But intersect a planet and that’s just data … until somebody asks about it.”

Lieutenant Stich responded with a smile that warmed Scarlatti all the way down to his toes. “My dad thinks my being in Fleet intelligence is exciting. I tell him I’m just a librarian: my job’s information retrieval.”

Scarlatti nodded toward his unit. “Yeah. Like I could call somebody on Mars myself … after the console told me who. But it’s a lot simpler to let the console talk to the data storage site directly.”

“Computers don’t go out to lunch,” Stich agreed.

Scarlatti’s implant chimed pleasantly, alerting him that new data hung in the air, to replace the calculated parameters. “Three hours?” he said in amazement as he translated the digits into human reality. “The beam was painting Mars for three hours? That’s absurd! Unless they were …”

Stich said, “And what were the chances that the beam would intersect a Fleet courier by chance?”

Scarlatti pointed to key his console. He had his mouth open to request the calculation when he realized that the other lieutenant hadn’t meant the question literally. “Oh,” he said, covering his embarrassment with a fixed grin. “Tiny. Had to be an accident, Jenna.”

“Maybe not. What about Mars?”

“Yeah. The Weasels meant to be noticed. Jenna, they kept a violently accelerating bomb between Mars and their ship for three hours. So people on Mars would look up. And see Halley’s comet explode. And that tells me a lot about their course.” His hands were moving.

At Scarlatti’s mutter-gestured command, his console threw up a course calculated with the addition of the new hard data. The intruder’s green line danced in the smoothly-perfect curve of masses in vacuum dancing through the sun’s gravity well. The cone of extrapolated paths (orange) had narrowed considerably.

“but we only know this because Sabot was in the beam. And that’s four points on a line, Jenna. Couldn’t have been planned.”

A chime from Jenna’s console drew the attention of both technicians. Scarlatti couldn’t hear the question Stich’s mastoid implant was asking her, but when she said, “Run,” the console spewed out loud the recorded conversation it had retrieved from Willy C’s files.

It made no sense at all. “What language is… .” he murmured, too lost in his own ignorance to notice the frown wrinkling his companion’s forehead.

Stich crooked a finger at her console. It obediently threw a holographic caption in the air above itself:

no known language.

possible cognates:

western european/pre-empire.

No known cognates within the thousand years since the collapse of the first starborne human civilization.

The speech, unintelligible even to the SCCS Willy C, stopped. Without prompting, Stich’s console threw up an additional caption:

time to next portion of transmission:

five hours, thirty-two minutes.

“Well, compress it, then!” Jenna snapped as though the console and not its programming had forced her to give that “obvious” instruction.

“Five and a half hours,” muttered Scarlatti, doing the computation for which he didn’t need his console’s help. “If the delay’s due to transmission lag”and he couldn’t imagine it being from anything else”it’s originating from well beyond Neptune. From the inner comets. Of course.”

Stich’s console began speaking in a different recorded voice, though the language was at least putatively the same. “The console picked the call out on the basis of the voice printone speaker’s a good match with the man who called Sitatunga and Broadcast Towers.”

“In Dallas?”

Jenna nodded. “Forty-three days ago. The other half of the circuit is supposed to be Gravitogorsk, Mars.”

“Then why the lag?” her companion asked in puzzlement. “Mars should require only a few minutes’ delay.”

“Supposed to be,” Stich repeated with a slight astringency for what she considered to be someone missing an obvious point. “With thirty seconds and a plot of comsat orbits, I can crash a Gravitogorsk circuit too, or any open circuit.”

“But could you do it from five and a half light-hours out?” Scarlatti prompted.

Jenna paused, pursed her lips in consideration. She looked beautiful. “With the Canaris’s navigational software to steady the transmission beam,” she said at last, “yes. Give me a starship’s navigational equipment, and I could tickle an orbital satellite any way you like. I could make anyone think a call was coming from Earth instead of… . The Oort Cloud is what we’re talking about, isn’t it? But you normally wouldn’t bother …”

“Unless you had an agent on Earth,” Scarlatti said, taking the verbal handoff from his companion. “And you wanted to give him the details of your plans so that he could prepare the propaganda campaign.”

Stich stared at the holographic solar system glowing above Scarlatti’s console. “Alec,” she said cautiously, “if you”

“factor in the distance and course calculated from the decreasing lag time between call segments. That’s their velocity component toward the Sabot. Hee hee hee! We’ll have their velocity vector. That’s more than they wanted to tell us.” Scarlatti’s fingers danced. The unit began to chuckle as it processed data.

The orange cone was now on the outer end of the green linethe course the intruder might have taken after his laser beam intersected the Sabot.

“then what’s on the inner side of the plotted course?” Jenna finished.

The red pulse and mastoid chime from Scarlatti’s console drew the eyes of both operators.

It was only a possibility, of course; a computer’s estimate based on the assumption that the Weasel ship had a specific intended goal, and that the vessel’s computer would choose the most elegant solution when it laid its course.

There was an event point from which a microwave beam from the Khalian ship would almost align with Mars on its way to Earth itself. A later event point from which the beam of a drive laser would intersect the Sabot and Mars sequentially. There was an event-point beyond

“Of course, they could’ve popped into sponge space and headed home,” Scarlatti muttered. “They’d be crazy to do anything else.”

“They haven’t done it yet,” said Stich. “An unscheduled sponge space entry within the solar system would’ve alerted the whole defensive array. If they stayed in normal space-time, they could assume no one would notice until …”

Scarlatti pointed, keying the console; then he paused while he decided whether to inform Commander Mown under the usual procedure, or to alert the Battle Center directly.

They’d have to be crazy.

Weasels are crazy!

“Battle Center,” he said. Moments ago he had watched one Commander Brujilla blow her career in six hot seconds. Likely enough he had just done the same. But beside him, Jenna Stich’s bald, finely formed skull was nodding approval of his decision.

Even if there were a ship prepared to take off at once, star-drive required incredibly complex equations that took time to complete.

And if the computed guess glowing above Scarlatti’s console was correct, the handful of scientists at Tombaugh Station on Pluto didn’t have very much time at all.

“Look, this is really some kinda training exercise, isn’t it?” said Pilot Trainee Rostislav. The fear was creeping up his spine. “Come on, Chalfond, a courier ship’s too small a box for us to be gaming each other.”

“It’s no exercise, Rostislav,” said Warrant Officer Chalfond, captain of the Sabot. “Shut up and worry about course coordinates.”

Chalfond had been in charge of a destroyer’s gun turret before a Khalian torpedo shredded her legs. Transfer to the command of a courier vessel on intrasystem runs could have been considered a promotion. At least it wasn’t forcible retirement.

She hadn’t considered it a promotion until now, when it seemed there might be a chance of action after all.

“Captain, the coordinates are set,” Rostislav said in a frustrated tone. “They’ve been set for half an hour. It’s the calculations to get there through sponge space that’re the problem, and I can’t speed them up by poking at keys myself.” He grimaced at the blank, pulsing depths within his omni.

The Sabot’s command console was a meter-thick pillar in the center of the vessel’s cabin. The console had three niches offset 120 degrees from one another, with seats facing inward. When the crew was at flight stations, they were almost touchingbut they couldn’t see each others’ faces.

“Moggs, are your guns ready?” Chalfond demanded.

“Is a bear Catholic?” Rostislav muttered with another grimace. Couldn’t she just keep quiet and let the software

“Huh?” said Crewman Third Class Moggs. Moggs spent all his free time running training programs at the gunnery screen, zapping pirates, meteor storms, Khalians, and whatever else the computer chose to throw at him. “I don’t get it, Rostislav.”

Rostislav wasn’t sure Moggs was bright enough to understand the difference between a training program and what was maybe about to happen.

“You know, Moggs,” the pilot said. “Does the pope”

“Shut up, Rostislav!” Chalfond snapped. “Moggs, are your”

“Captain,” said Rostislav. “The console is ready to start sequence.”

“Action Stations,” said Chalfond. “Pilot, start sequence.”

“Sequence started.” Rostislav tapped a key and waited for the shift. It always felt like being turned inside out. Captain Chalfond never reacted. She claimed that she had become used to it. Rostislav believed that the captain was lying.

“Moggs, are your guns ready?” Chalfond repeated in a calm voice. Rostislav could hear the tap of keys from by her side console, but his screen was loaded with flight data and didn’t echo whatever Chalfond was setting up.

“Yes, Captain.”

“C-captain Chalfond,” said Rostislav. “What if it really is a Weasel armada we’re jumping into the middle of? I mean, I know there won’t really be anything there, but if there was … ?”

“Don’t worry, kid,” said the legless warrant officer in what she must have thought was reassurance. “They’re scrambling everything in the system! All we gotta do is take the Weasels’ minds off Tombaugh Station for a couple minutes.”

It was a very short transit. The Sabot made a blurring lurch back into normal space-time. This time, Rostislav had too much on his plate to notice the momentary nausea.

“I have a target,” said Moggs.

“Magnetics up,” said Rostislav. The magnetic shielding that dispersed the effect of plasma bolts was one of his responsibilities at Action Stations, though he was only vocalizing what the green sidebar on the captain’s screen told her.

“Unidentified vessel,” Chalfond ordered over the tight-beam laser communicator. “Drop your screens and prepare to be boarded.”

The Sabot gave a triple shudder. Its load of ship-to-ship missiles had toggled off in accordance with the engagement sequence that Chalfond programmed while they were still in sponge space.

“Chalfond!” Rostislav shouted. “We can’t shoot before we know”

Six screens, the outside views, flashed green and were blank. The data displays were unchanged, except that the ship’s skin temperature was rising fast. High flux on that laser. A merchant ship would be boiling away. Rostislav recognized that shade of green from days ago and said, “Never mind.”

“Stay alert,” Chalfond said. “That green light can’t hurt us much, but” The Sabot shuddered again. A transient of orange light sparkled within the depths of Rostislav’s screen, fogging the data there momentarily. Magnetic fields, Sabot’s shielding, twisted in the flow of plasma bolts.

“Taking evasive action,” said Rostislav in a steady voice pitched an octave above his normal speech. Khalians. Weasels.

“Gunnery officer, open fire,” Chalfond said.

Six-round bursts from the ball turret in the nose hammered the hull sharply. Training programs didn’t duplicate the effect on the Sabot of miniature thermonuclear explosions, contained and directed by laser arrays in the breaches of the twin turret.

The outside cameras came back on.

Rostislav had brought the courier vessel out of sponge space at the rim of Pluto’s gravity well, on a reciprocal course to that computed for the intruder by the Canaris’s Battle Center. Sabot’s real-space velocity was low, but somebody on the command and control ship had really been on his toes: the Sabot was headed right down the intruder’s throat, and the Weasels’ own significant fraction of light speed gave Chalfond’s missiles a mere thirteen-second trajectory.

Another plasma bolt snapped close enough to set a relay in the Sabot’s guts singing, but that was chance. Rostislav had cranked in lateral accelerations that took the courier out of its ballistic path. The side-thrusters pulsed with computer-generated randomness. That was unpleasant to the crewbut not nearly as unpleasant as taking a direct hit that would flatten the magnetics and vaporize the Sabot’s forequarters …

The green light flashed and was gone, and was back, and held. Not much of a weapon, that, not to today’s mirror-surfaced warships.

The red pip of the Weasel in the center of Rostislav’s screen calved a trio of additional pips: missiles. They winked out instantly. Moggs couldn’t have reacted to the actual target so quickly, so he must be firing at where and when he expected the Weasels to launch.

The gunnery training programs were worth something after all.

So was Moggs, despite his room-temperature IQ.

One of Chalfond’s missiles vanished from the screen. The Weasels had switched their guns onto the missiles homing on them, but there wasn’t time to

The red pip blurred.

“She’s trying to enter sponge” Rostislav warned.

The pip sharpened, then expanded into a fuzzy cloud quite different from the blurring of a moment before.

“space.”

Ships had to lower their magnetic shields before entering sponge space.

“Game’s over,” said Moggs simply.

The two remaining missiles plunged toward the heart of the cloud. Chalfond detonated them with an abort command. There might be debris worth examining. “Gunnery officer,” she ordered, “secure your weapons. Pilot, bring us around.”

Pilot Trainee Rostislav found that his hands were shaking so badly that it was several seconds before he dared touch his controls.

Twenty years before, Commander Antonio Soler, a brilliant young officer, made a brilliant marriage and resigned his commission to follow a brilliant academic career. The marriage hadn’t lasted, though friends argued about whether Antonio’s drinking was the cause or an effect of the failure. The academic career went by the boards at about the same time as the marriage; and, though he dried out, the brilliance remained in eclipse.

Antonio Soler came back to the Fleet, to serve out the seven years remaining before he was eligible for a full pension. Few military positions require brilliance. The Fleet was glad to give the ex-commander warrant rank and command of Mine Warfare Vessel 774T.

“Region Twelve cleared, sir,” reported Yeoman Second Class Teddley as she began to furl the gossamer static lines with which MWV 774T had cleared another assigned sweep area of debris from the Khalian vessel. There were a dozen ships involved in the hasty search, but only the 774T and her sister ship MWV 301A were really designed for the work. “Shall I proceed to Region Thirteen?”

Warrant Officer Soler was standing with his hands on hips, jaw out-thrust. Slightly tilted on Velcro slippers, he was facing but not really viewing the main navigational screen. He didn’t respond to his subordinate’s question.

“Ah,” Teddley said. “Sir? Shall we proceed to Region Thirteen while we process the drag-load from Region Twelve?”

“What?” said Soler, turning with the confused embarrassment of a man caught viewing himself in the mirror of his mind. “What? Yes, yes, of course.”

Teddley chimed a warning of the coming course correction. It was a momentas Teddley expectedbefore Soler himself realized he needed to get into his own acceleration couch.

“Have you been considering the enigma of why the Weasels would attack Halley’s comet, Teddley?” Soler demanded.

“Yessir,” said Teddley. She programmed the burn. It was a rhetorical question; it wouldn’t make the slightest difference whether she responded yes, no, or maybe.

“Let me postulate a plan,” said Soler, “a plan for Weasels. I’m a brilliant Weasel, yes? I know I can’t invade Sol system. It crosses my mind that I barely have the power to destroy an ice ball ten miles across. That shows no immediate personal profit, so as a Weasel I may well stop thinking at this point.”

“But let me attempt to think like a human politician. We Weasels know that they’re a cowardly lot.” Soler smiled at Teddley; Teddley smiled back. Burn in twenty seconds.

Soler said, “If something as prominent as history’s most famous comet is suddenly blasted into a vivid cloud of ice crystals, won’t the human government panic? The results must be to our favor. Ships from the Fleet will be withdrawn to Earth for defense there, instead of patrolling regions we Weasels can raid.”

“Yessir.” The vessel’s thrusters fired under orders of the navigational computer. The acceleration was mild, less than a tenth-G, as MWV 774T eased through black sky, sifting vacuum.

“Well, but you see, the threat has to be credible,” Soler continued. “The death of Halley’s should look like the first move in an invasion. So my next move is to get my tiny ship out of the solar system, quick, before Earth’s defenses can get to me. Otherwise”

Teddley was intrigued despite herself. “Otherwise Earth’s navy will find themselves looking at the blasted remains of one little ship”

“Too small to invade a decent hotel!”

“Right. But they raided Pluto.”

“Why?” Soler demanded. “They could have launched and disappeared. They could have been gone while the laser light was still in transit, and the message to their spy, too. Gone before the comet was even touched.”

“Um. Well,” Teddley said, “they thought they could get away with it. Immediate profit. The captain couldn’t make himself go home without something for his trouble. Weasels are like that.”

“And now we know there’s no invasion fleet.”

Teddley shrugged. “They got caught. Willy C’s crew was on the ball. But they didn’t expect to get caught.”

“But Tombaugh Station is a trivial target,” Soler protested, treating Teddley as one of his erstwhile graduate students rather than a military subordinate. “Pointless compared to the propaganda effect that was the object of the exercise!”

“Sir,” Teddley said, “somebody who’s embezzled millions doesn’t pass up a wallet he finds on the sidewalk. A crook is a crook. A Weasel’s a Weasel.”

Soler’s console pinged three times, indicating that Karelly, in the vessel’s net bay, thought he had an emergency. Recalled to his duties, Soler grimaced and said, “Karelly? Go.”

“Sir! We got something this load that I think you gotta see. I think the sector commander’s gotta see it!”

“Calm down, man. You’re carrying a camera? Show me.”

Soler peered at the blurred, off-color image. “It’s frozen,” Karelly babbled, “and the blast has chewed it, but look”

“Right. Thank you, Karelly. Teddley, do you see what I meant? No Khalian would have thought of any such plan. The rewards can’t be eaten or worn or spent. Phone the Canaris for me, will you? Sector commander.”

From the surface of Mars, from most of the moons of Jupiter and Saturn, from any worldlet with a black sky, a good eye might see the murder of Halley’s comet. One would have to know where one was looking; and then the expanding cloud of ice crystals was a tiny pale smudge, quite different from the sharp point that would be a star or planet.

But beneath the murky atmospheres of Venus and Earth, or within the rock of Ceres and Vesta and hundreds of other asteroids, the pale cloud filled a billion omni screens. A million individual shards flowed twinkling toward the eyes of two billion voting citizens.

Noel Li spoke offstage in an edgy voice with precisely chiseled consonants. “The Fleet reports no sign of the invaders. But fourteen years ago, the Khalian invasion of Rand looked like this”

Ten thousand individual ships flowed twinkling toward the viewer’s eye. The fourteen-year-old omnitape of the invasion of Rand looked dauntingly similar to Halley’s comet exploding.

Krasnowski of Civil Affairs was professionally calm, almost sleepy-looking, as he met Noel Li’s huge dark eyes in the omni. He waited at the edge of the sector commander’s office, out of sight of the cameras which would send Eriksenas a holograminto the Meeting Hall of the Alliance Senate, as soon as the sector commander has something to say.

Krasnowski’s aide had less experience than his chief in the terrors of political brinksmanship. The lieutenant commander wrung his hands as he scurried in and whispered in Krasnowski’s ear.

Krasnowski listened, then waved his subordinate back to the commo center where he would be ready to relay the next frantic message from groundside.

Eriksen cocked an eyebrow. Civil Affairs made another negligent gesture and said, “The natives are restless, Admiral. Perhaps you might throw them a few well-turned phrases while we wait for the”

“Not until” Eriksen said, turning toward Captain Crocker, who sat beside Krasnowski and Commander Mown.

Military Affairs met his superior’s glance with a look of icy indifference. The expression was as false as a papier mache cannon, but it was perfect in its artistry.

“Not until Captain Crocker reports,” Eriksen continued. “We have one chance to retrieve this situation, and we aren’t going to lose it by being” Crocker’s aide ducked in through the door, handed him a brief sheet of hard copy, and disappeared at once. “overanxious.”

“Thank God,” Crocker muttered. “We’re all right,” he added, rising from his seat to hand the flimsy to Eriksen. “There was only one small ship, as we conjectured, and it’s been destroyed.”

Eriksen waved the document away. Nothing would mar the serene polish of his desk when the cameras went on in a few moments. “There’s no possibility of a garbled transmission?” he demanded.

Crocker shook his head with a satisfied smile. “None whatever,” he said. “The ship that made the kill was a courier, the Sabot. They brought the news back themselves while later arrivals continued to check the area.”

“All right,” Eriksen said, composing his features into stern, fatherly lines. He stood; simultaneously, his desk sank until its top formed a flush surface with the decking. “I’ll see them now.”

The outlines of the sector commander’s office vanished from his vision. He stood instead in an illusory hall large enough to hold the three hundred Senators and more than a thousand accredited Observers who deliberated on the course and finances of the Alliance of Planets. President Ssrounish faced him from her central dais, while rank after rank of seats mounted in curves to either side.

A surprising number of the seats were empty. Or not surprising, given the widely publicized belief that this room would be the first target when the Khalians’ ravening armada reached Earth.

“His Excellency Lars Eriksen,” boomed the hall’s Enunciator. “Admiral of the Red and Commander of Sol Sector!”

Eriksen waited a three-beat pause. “Madame President,” he began. “Honorable Senators and Observers of the Alliance of Planets …”

Pause.

“Today I come before you to admit error and apologize on behalf of the Fleet.”

There were as many gasps as there were filled seats in the Meeting Hall. Several members rose and scuttled toward the exits, certain that they had just received confirmation of their blackest fears.

“For many years,” Eriksen continued in rotund tones, as though he were unaware of the commotion he had caused, “the Fleet has maintained a secret testing facility on Halley’s comet. I must now admit to you that an inexcusable lapse in safety precautions occurred, causing an experiment to go disastrously wrong.”

Pause.

The hall gasped and burbled, like a catfish pond at feeding time.

“Through that error,” Eriksen said, “Fleet scientists have destroyed Halley’s comet.”

Shouts of amazement.

“We must be thankful,” Eriksen went on, knowing that the Enunciator would raise the volume of his voice to compensate for the ambient noise, “that no lives were lost in the occurrence … but I realize that this is small comfort to those inhabitants of Earth, and to their unborn descendants, who will lack forever one of the crowning glories of the solar system.”

Several of those listening in the Meeting Hall were literally dancing in the aisles. A portly Observer attempted a cartwheel and wound up crashing into a desk three ranks below her own. No one seemed to care.

“There is only one recompense adequate to the scale of the error,” Eriksen said. “I have contacted Fleet headquarters”There hadn’t been anything like enough time to inform Port Tau Ceti of the situation, but that lie would be lost in the greater one”and have received the full approval of my superiors for the following arrangement.”

He paused again, letting the room quiet to increase the impact of what he was about to say.

“We of the Fleet,” the sector commander boomed, “at our sole effort and expense, will rebuild Halley’s comet, using material from the Oort Cloud. The project is expected to take three years”Eriksen could imagine Mown nodding approval at the fact his superior had remembered the correct figure”but at the end of that time you will have a comet identical in orbit and composition, not to the Halley’s of two days ago, but to a younger Halley’s comet as it was seen four thousand years ago by the Chinese. A young Halley’s comet with thousands of years of life ahead of it.”

It was almost ten minutes before the cheers and clapping died down enough for Eriksen to signal an end to his transmission.

“God!” he said, flopping backward before he checked to be sure that his chair had risen high enough to catch him. It had.

“Brilliant, sir!” Krasnowski was saying. “Absolutely brilliant!”

“Monitor the omni,” Eriksen muttered with his eyes closed against the memory of over a thousand politicians with their mouths open. Cheering now; but it could have been his blood for which they shouted.

When the admiral looked up again, he saw to his surprise that Captain Crocker was frowning, and even Commander Mown looked concerned as he read the sheet of hard copy Crocker had passed to him. “Yes?” Eriksen demanded, waiting for the worst, waiting to learn there really was a Khalian invasion force …

“There wasn’t much left of the ship the Sabot nailed, sir,” Crocker explained. “Some Khalian protoplasm. And they did find an arm in a uniform that doesn’t match anything in our files to date. Here.” Crocker gesture-muttered, and the picture in the omni blurred.

“I didn’t think Weasels wore uniforms at all,” Eriksen said carefully. What was he looking at? A jittery hand held something in front of an omni camera. Eriksen couldn’t make it out. Double image?

A human hand held … held a human hand, pale with frost, and half of the raggedly torn forearm.

“Yes, that explains it,” Mown muttered. “It bothered me that Khalians understood human psychology so perfectly.”

Admiral Lars Eriksen’s guts felt as though he’d just dropped into sponge space, except that the sinking sensation went on and on.

End note to The Murder of Halley’s Comet

[In 1989 I was co-editing The Fleet with Bill Fawcett, a space-opera shared universe series. Bill suggested that I ask Larry Niven for a story, which I did. (I’d been working with Larry on another project which, thank goodness, had died quietly.)

Larry didn’t have time to write a story, but he said he’d plot one and do a polish pass if I wrote it; that’s what we did. The result was “The Murder of Halley’s Comet.”]