In a vast, sprawling space station orbiting Jupiter, a young Lieutenant read a report on his screen and stiffened. "Sir, we've got positive contact," he said. "Alfa Charlie gate guard reports a single high-acceleration intruder."
The Brigadier General practically choked on his coffee. He hooked the hot sipper to his desk-station — a reflex action, from years of working in freefall like this. "How the hell did it get past the gate guard in one piece?"
"The details are a bit erratic, sir," the Lieutenant replied. He snorted derisively. "They've been customs inspectors for so long I think they've forgotten how to fight. I can't be sure I'm interpreting this correctly, but it sounds like they're saying the intruder made transit at . . ." He squinted, to make sure he was reading it right. "At five permil."
The General's eyes snapped wide open. "Five permil? Fifteen hundred klicks per second?!"
"That's what they claim, sir," the Lieutenant answered. He punched a few keys. "The radar log they attached to their message — ooh. Ouch. They weren't kidding, sir. The intruder really was travelling at 5 permil. And pulling some pretty strong evasive maneuvers. This log only shows one minute's worth of records, but for that entire time their doppler radar confirms that it was pulling a hundred g in various random directions."
"Damn," the General muttered under his breath. Defensive doctrine had been built around the notion that, since civilian spacecraft transited hyper holes slowly to avoid boundary shear, a military intruder would likely do the same. There had been some naysayers in high command who'd claimed that it was possible for fighters, or even big bulky carriers, to line up precisely enough with a hyper hole from far enough away that they could get a running start and still make it through intact. Their concerns had generally been voted down, of course; but just to throw them a bone, contingency plans had been developed to permit a Gate Guard to lock onto and destroy craft moving as fast as a full 1 permil. That was 300 kilometers per second. Surely, at such a breakneck speed, the chances the intruder would accidentally cripple itself on the way through would have far outweighed the increased odds of slipping past an enemy Gate Guard unharmed. But even that hadn't placated the alarmists. So, despite all good sense, the high command invested in targeting systems that allowed each Gate Guard's weapons to hit suddenly-appearing targets going twice that fast, at a ridiculous 2 permil. It was sheer, wasteful overkill, and everyone with a working brain knew it.
And yet, here was an Alpha Centaurian intruder — and it had to be a fighter, given its acceleration — who'd just whizzed into the Sol system going two-and-a-half times that speed. The damn xorns had just proven, in frightening fashion, that they had a high-speed guidance system that could indeed thread the needle with far more accuracy than they had any right to. The entire Gate Guard system had just been rendered obsolete.
The Brigadier General grunted, then shook his head and returned his attention to his Lieutenant: "What's the bogey's course?"
"Uh . . . at last count, it looks like the craft was pulling a hundred-g powered turn. Best estimated trajectory is that it's going to be headed straight toward us."
"They're attacking Station Jove?" the General puzzled. "With one fighter? They've got to be kidding. The xorns must be testing our defenses. Ah well," he turned to a young curly-haired woman at another station, "Put us on condition yellow, Sergeant, we're going to have company in a day or so."
"Right, sir," Sergeant Li replied. She hailed from North Mars and, like most North Martians, was Chinese. She was also one of the few that had learned how to speak Mandarin — though not well enough to have a convincing accent, since precious few still kept regional languages alive. She switched on the intercom and engaged the corridor lights. "All personnel, yellow alert. I repeat, yellow alert. This is not a drill . . ."
Deep in the yawning gulf between the Sol/Alpha-Centauri hyper hole and Jupiter, the semi-intelligent electronic brain aboard the lone fighter went meticulously through its battle projections. This pre-programmed powerhouse could withstand accelerations that would have turned any living occupants into paste, and its hot-fusion engines provided it with all the thrust it could use. Although it had its own arsenal of weapons and could perform any number of sophisticated battle maneuvers, fighters often inflicted the greatest devastation on stationary targets simply by ramming them. Much debate within military circles had centered on whether there was really any difference at all between a fighter and a guided missile, especially given the near-S.I. level of smarts the most recent generation of cruise missiles posessed. The only concensus anyone had ever reached was that a spacecraft was a fighter, and not a cruise missile, if it was cheaper to reuse than to expend.
Suicide ramming was not, however, in this particular fighter's primary mission programming. This time.
Orbiting Jupiter so close it nearly touched its outer atmosphere, Station Jove bristled to life. The station itself — nicknamed Cape Jovial by its inhabitants — was little more than a vast skeletal framework of docking clamps and conduits, barely armed and scarcely armored. Its military might, and importance, came from the enormous fleet of spacecraft docked there. Sol's military had rightly determined, long ago, that every heavy object in space could be turned into a deadly missile, capable of smashing any fixed installation to rubble with little effort. The only defense was to keep all equipment and supplies mobile. Even fuel storage tanks were absent from Station Jove's main structure, deuterium instead being supplied by a flotilla of lumbering Transmute-Tanker spacecraft that made regular runs to and from the Jovian atmosphere.
Now, with the alert having sounded, crews scrambled to make every docked spacecraft voyage-ready. So long as the yellow alert lasted, they had to be ready at a moment's notice to undock themselves and scatter from their home. One by one, the fuel tankers, fighter carriers, personnel transports, and other assorted craft came to life and reported in.
"We've got three no-goes, sir," the Sergeant reported. "Tanker eleven and Bus Juliet are both down for maintenance, and their Commanders say they're not spaceworthy. The old carrier Mercury's completely mothballed, of course. Everyone else reports ready to head out."
"Okay," the General clapped and rubbed his hands together as he turned to his tactical board. "Options! Ragaji, who can we send?"
Major Ragaji, the chief tactical officer, scanned the board and replied, "There're six carriers here, sir. Two of them are already undocked for patrolling."
The general snorted, looking at the labels on the big screen. "Send Zelta out with orders to intercept and destroy. Keep the other deployers in reserve, this might be a diversion."
"Right, sir," Ragaji responded; then, tapping the tiny blip on the screen labelled Zelta, he selected target and mission and sent the dispatch on its way.
A scant few kilometers away, the narrow radio beam carrying those orders landed on a parabolic receiver dish. They could get away with using beamed radio at such a short distance; if they'd wanted the signal to cross more than a few million kilometers of interplanetary space error-free, they'd have had to use an ultraviolet laser instead. A deployer needed to be able to receive new orders at those kinds of distances, if it was to carry its fighters throughout the Solar system.
"We're up!" Colonel Yindras called out. The air in the cramped Command Center, deep in Zelta's armored heart, went tense. "The intruder's ours! Take us out and clear, one gee."
"Right, sir," the pilot replied. Zelta was already clear of the station, so she could go to main thrust immediately. She throttled the QC&C engine smoothly upward until it produced a steady 9.8 meters per second squared. The back end of the spacecraft was now down.
Fighter deployers — sometimes called fighter carriers, sometimes called mobile bases — existed as a consequence of the two main, competing engine technologies. If you wanted to intercept an intruder or slip past a defender, you needed to out-accelerate him, which led to a quickly-spiralling arms race of more and more powerful spacecraft engines. Living flesh had a nasty tendency to squish if you subjected it to more than a dozen or so times Earth's surface gravity, so eventually the human factor was removed from the equation entirely, and unmanned fighting vessels became every nation's front line soldiers. Electronics were toughened to withstand the dozens upon dozens of g, struts and stresspoints were built out of sturdier and sturdier alloys, fuel hoses became fuel girders, but there was one fundamental conundrum in spacecraft design that no amount of engineering could overcome, and that was the hot-fusion engine's voracious appetite for fuel. An unmanned fighter couldn't waste mass on a super-efficient QC&C fusion engine, because despite their efficiency such engines had a positivley abyssmal thrust-to-mass ratio; half the spacecraft would have to be engine just to get a meager 40 or 50g of acceleration. By contrast, even the tiniest proton-deuteron hot-fusion engines could produce ungodly levels of thrust, but had barely 40% of a QC&C engine's exhaust speed. And thanks to the bitter reality of Tsielkovsky's equations, a 60% reduction in exhaust velocity translated to many, many times the amount of fuel required for a given mission. A modern fighter was little more than an armored flying tub, carrying more mass in fuel than the all the rest of the spacecraft put together.
Which meant, ultimately, that it was far more efficient to tow a fighter via a low thrust QC&C engine, than to have it fly there on its own. A fighter deployer did just that. It carried fighters, their fuel, their ammunition, their repair and maintenance crews, spare parts, and all the tactical capability necessary to send its fighters into battle and retrieve the survivors at battle's end. And since these deployers made such tempting strategic targets, they also carried their own layers of whipple armor and their own small arsenal of defensive weaponry.
Colonel Yindras turned to his chief tactical officer. "What's our target's current distance and vector?"
"Uh . . ." the Lieutenant took a moment to get his bearings, "Latest report shows the intruder at three-eight-zero million kay-em, vector three-five-nine by plus zero Ecliptic — almost straight toward us."
Yindras nodded. The Sol/Alpha-Centauri hyper hole, from whence their attacker had winked into existence, had its own crazy orbit around the sun. It was the first linked hyper hole ever made, and its creators on Sol's end were so worried about making their experiment work that they didn't give any thought to where it would end up years down the line. Every eleven years, it grazed the outer edge of the asteroid belt, then five-and-a-half years later it was more than a full A.U. farther out than Jupiter. In some thousands of years, in fact, it would meet Jupiter and send a huge swath of that gas-giant's interior into the Alpha Centauri A system as it passed through. That would be a sight to behold. Right now, though, the hole was about a quarter of an orbit ahead of Jupiter, as it had been for the past year or so. Any attacker that made it past Sol's Alpha Centauri gate guard would have to cross that two-and-a-half A.U. gap to reach Station Jove.
That position report on the intruder was also, of necessity, out-of-date. 380 million klicks was over twenty light-minutes. That blip on his tactical officer's thermal-infrared scope showed where their prey used to be twenty-one minutes ago, not where it was now.
"When we're out of Cape Jovial's hazard zone," the Colonel addressed his remote ops officer, "Deploy Zelta Cee and Zelta Dee. Order them to engage and destroy the target. We'll hold Zeltas Aay and Bee in reserve on the off-chance the enemy makes it through."
Captain Ganges, the remote ops officer, furrowed her brow. "Zelta Dee, sir? D'you really trust it with a live target?"
"We've gotta give the new Directional a real shakedown some time," Colonel Yindras answered. Of the carriers stationed at Jupiter, Zelta was the Solar Space Force's premier Guinea pig. Its fighters served as a test bed for every harebrained experiment in military technology that the politicos saw fit to see in action. Nowhere was this more evident than with Zelta Dee's frighteningly new Directional Screen. Some yahoo in a lab had managed to tweak the collumators normally used in a magnetic snare so that they could project a short-range continuous field along a single narrow arc. If the fighter could aim this projector directly at an attacker, the field would offer far more resistance to charged particle weapons than the omnidirectional magnetic protection field most combat spacecraft used. If turned up high enough, it could even, in theory, nudge incoming ferromagnetic slugs and shrapnel so that an otherwise direct-hit would be reduced to a grazing blow or even miss the fighter entirely. The directional screen had worked fine in the laboratory, and in one or two controlled tests against stationary spaceborne guns, but it had never seen combat. Worse, it would interfere with its fighter's more conventional magnetic protection field, so both systems couldn't operate at the same time. If the directional screen wasn't between the attacker and the target at the instant a plasma burst arrived, the target would have nothing but its whipple armor to keep its electronic guts alive.
Station Jove's hazard zone, inside of which all thrust levels and exhaust vectors had to be carefully controlled, extended for five hundred kilometers in all directions. At Zelta's modest one g of acceleration from a standing start, it would take a little over five minutes before they were clear. In that time, the fighters' support crews would have to make their final checks to ensure that their charges were fully loaded, armed, sealed, and ready for action. At this moment, three crewmembers were out in compression suits, inspecting and adjusting two problem spots on Zelta Dee's armored surfaces that the robots couldn't reach, and a similar cranny on the surface of Zelta Aay. The steady 1g thrust from Zelta's engine meant they had to cling to the sides of the fighters like rock climbers on a sheer cliff face, and still make it back to one of the safe zones on Zelta's hull in the five minutes before fighter deployment — all routine.
The very name "fighter" was deceptive to any student of aviation; these were not the tiny winged needles of air-to-air dogfighting, but enormous armored cylinders sixty meters across and a couple hundred meters long, weighing in at over a hundred thousand tonnes apiece without fuel. Aside from their engine bells and their separate internal fuel tanks for hydrogen and deuterium, most of their bulk was taken up by layer upon layer of metal armor. Each layer of armor had to be separated from its neighbors by a wide vacuum gap, to ensure that if the outer layer got hit by something hard enough to make it explode, the next layer in would only take a diffuse spray of vaporized debris. It was the same basic principle that protected satellites from micrometeors, or that protected the old seagoing aircraft carriers from being sunk by a single torpedo. So many layers were sandwiched on top of each other that the actual functioning hardware at each fighter's core was barely half the fighter's full diameter. The outermost layer, also, had to be polished to a mirrorlike shine, in case its attacker sported lasers. The same kind of octuple-decker armor-vacuum sandwich also protected Zelta itself, should its enemies somehow get past its four fighters.
With all inspectors in and the hazard zone at last behind them, Captain Ganges called out, "Clear and safe! Remote S.I.'s showing green. Zelta Cee and Zelta Dee, deploying!" Two enormous hydraulic clamp ensembles released their cargoes in unison, their clangs and thuds echoing reassuringly through the Command Center. Two dark video monitors flared into life — windows were impossible this deep inside the carrier — showing two gleaming patchwork cylinders falling away and behind them. For a brief instant, the logo of the Solar Federal Government, emblazoned on a tiny corner of Zelta Dee's outermost armor, flashed in the distant light of Sol herself. Ganges turned to Colonel Yindras and asked, "Confirm attack and destroy orders for Cee and Dee against intruder, sir?"
"Confirmed," Yindras intoned. "Gun him down."
Ganges grinned wryly, and typed the shorthand command at her console. She could have just told the fighters what to do in plain language — their S.I.s were more than sophisticated enough to understand — but there was a certain thrill and comfort in writing out their orders in their ambiguity-free native tongue. Each fighter's S.I. was a temperamental prima donna with its own subtle quirks; shorthand commands helped cut down on misunderstandings tremendously. Acknowledgement of her orders came back in a heartbeat, delayed only by the split instant needed to encrypt and decrypt the signals. This was the last time she'd have the luxury of instant communication until the battle was over. "Orders sent, sir."
Even before their orders had been issued, each of the two fighters had already spooled up its main engine for the moment it would be needed. Now, nearly a kilometer behind Zelta, each began feeding hydrogen and deuterium into that aft-facing pressure-furnace at twenty tonnes per second. Engine bells flared into superheated brilliance. Frames shook, joints creaked and groaned, components sagged, until at last they reached full throttle at a hundred times the force of Earth's surface gravity. No living thing could survive such crushing environs. They overtook their carrier almost instantly and sped off toward their prey: a tiny thermal blip nearly a thousand times farther away from them than the Moon was from the Earth.
On her forward video monitor, Captain Ganges watched the two powerhouses pull away and vanish into the distance. She'd seen it countless times before, in one training exercise after another, but this time her charges were going after live prey that could shoot back. In many ways, those fighters were like her children, and she worried that they might not be coming home again. It all depended on whether their S.I.s chose the right combat algorithms at the right times to outplay the intruder.
Inside Zelta Dee's semi-intelligent electronic brain, these scenarios were already playing out in mock battles. As this was a two-fighter operation, one of them had to be chosen as the master coordinator; this time it was Zelta Dee's turn. When the time came for decisive action, Dee would have to send the order to Cee to split up or stay tight. That wouldn't happen for a while, though. If they and their target both accelerated toward one another until they were closing at 10 permil relative — which would take at least another twenty-five minutes in and of itself — their rendezvous wouldn't happen for at least another thirty-one hours. If the target changed its acceleration vector, either to change targets or to run, that figure would be higher, but not much higher. And it had nowhere to run to, except back to the hyper hole, where it would be easy prey for the Gate Guard.
With the data coming in from Zelta Dee's passive sensors, though — the target's angular location, its blue shift, the brightness of its exhaust plume at six diffferent infrared frequencies, etc. — the intruder was still accelerating directly toward Station Jove in an utterly predictable manner when the light left it 19 minutes ago. When Cee and Dee's radar echoes finished their round trip — assuming the target wasn't running with Active Radar Absorption — they'd refine their radial velocity measurements and add cross-section and distance snapshots to this data.
Thus began the waiting game. . . .
Although the Centaurian fighter didn't intend to suicide ram, its mission was still more or less a suicide mission. Its carrier, named Gellimand after the Centaurian personification of light, was back on the other side of the Sol/Alpha-Centauri hyper hole, and had no intention of risking itself or its crew just to get its number 3 fighter back. Gellimand 3 had rolled the dice, blasting through the hole and zipping past Sol's Gate Guard, and would roll the dice several more times before its mission was accomplished. Being lucky enough to survive the trip back, especially when the Gate Guard could see it coming, was almost out of the question. It kept its throttle steady at 100g, even as it registered the distant flares of two enemy fighter launches that were doubtlessly heading its way.
After 25 minutes, Zelta Cee and Zelta Dee had both accelerated to 5 permil. The enemy fighter, likewise, had completed its powered turn so that it was now moving 5 permil straight toward the Zelta fighters — at least per the 18+-minute-old signals that had reached the Zeltas by this point. That made the closing speed a comfortable 10 permil relative. Zelta Cee and Zelta Dee both throttled their engines down to their ready-idle states, and watched their target to see what it would do.
But their target continued to accelerate. This was half expected. The target was probably looking to avoid fighter confrontations along the way to its goal. By the time the Centaurian fighter's engines finally cut out another 25 minutes later, it was closing on Station Jove at 10 permil, which meant that the Zelta fighters were now closing at 15 permil relative. That bumped their meeting time up to a scant 22 hours from now. If they wanted to match speed with the enemy at rendezvous, they'd have to cancel all their forward velocity and accelerate twice as much in retrograde — a 75-minute burn at 100g — so that all three of them would be hurtling toward Station Jove at 10 permil when they engaged each other. Combined with the 25-minute burn they'd just completed, this would eat up fully half of their delta-v budget.
And if their target tried some tricky maneuvers to get them to burn up even more of their fuel, or actually accelerated toward them . . .
There was another option. Since they were two fighters, one of them could keep closing at high speed without slowing down, or at least without slowing down as much, and make a pass at the enemy on the way by. The odds of success on such a strafing attack were less than stellar, but they were better than the odds if their rendezvous missed. So . . . they'd both start decelerating when the time came, and if the enemy didn't pull anything fancy to try and elude them, they'd both make a velocity-matching rendezvous with the target. If their target did pull another high-g maneuver, though, Zelta Dee would continue to attempt a rendezvous, while Zelta Cee would merely do enough of a deceleration burn to neutralize the 5 permil of outward speed it had relative to Station Jove. The target would whiz by Cee at ten permil — or more — and, luck willing, it would run into something Cee threw in its path.
Some 21 hours after starting out and twenty million kilometers from the intruder, Zelta Cee and Zelta Dee pointed their engines directly at the oncoming Centaurian fighter and throttled back up to 100g. It was still only a radar blip and a tiny point on their thermal scanners at this moment, and would have been utterly invisible to the naked human eye — were there any humans nearby to look. But at the insane rate the target was closing with them, Zelta Dee needed to cross another ten million kilometers at full acceleration, just to match its target's current speed. If the intruder decided to accelerate toward them, they could use up the entire 20-million-klick runway lying before their target.
And since they were now decelerating, it was time to release the cruise missiles.
Sixty-seven seconds later, Gellimand 3 saw the launches and the engine telltales. The cruise missiles would be easy to deal with, but if those two Sol fighters both managed a rendezvous, they'd probably kill it. Thermal decoys weren't an option; a fighter's vast surface area meant it dumped a lot of low-temperature blackbody radiation into space. For one of those tiny spheres to match such a bright-but-low-frequency thermal profile, its emitters would consume enough power to produce their own heat signature with its own peak frequency. No, if Gellimand 3 was going to make it through this, its only recourse was to accelerate toward its ultimate target, and hope its attackers wouldn't have enough run-up room to match speed. It pointed its nose straight at Station Jove, and drove its main engine up to full power.
And sixty-six seconds after that, the Zelta fighters saw the intruder start accelerating toward them. It was decided. After 5 permil of 100g deceleration, Zelta Cee would cut its engine, leaving it with the bulk of its delta-v budget unburned but with the attacker hurtling toward it at 10 permil relative or more. Zelta Dee would make a rendezvous, and hope the intruder didn't force it to burn so much fuel that it would no longer be able to return to its carrier.
Gellimand 3 had cut its engine after five permil of acceleration. It would be enough. One of its attackers had throttled back, reducing its threat to a single impending high-speed pass; the other was still furiously burning away its fuel supply in a mad attempt to match speeds. In fifteen minutes that first fighter's high-speed pass would arrive, but for now Gellimand 3 had its mechanized hands full with the cruise missiles. It turned sideways and throttled up to the full 100g, and commenced evasive maneuvers. Titanic attitude thrusters, each a small hot-fusion engine in its own right, fishtailed the fighter randomly so as to throw the missiles off.
The missiles were tracking it, as Gellimand 3's S.I. had expected. Each little blue-shifted blip appeared motionless against the background stars, no matter which way the fighter's engine pointed. That could mean only one of two things: either they were very far away — which the quick radar returns confirmed they weren't — or they were homing in on Gellimand 3, matching each of its dodges and jinks with identical maneuvers. As dangerous as that made the missiles to Gellimand 3, their apparent motionlessness also made them easy prey for point defense. Gellimand 3 sported several short-range proton cannons which, at high power, could blind a fighter's radar if captured by a magnetic field or vaporize a few layers of its armor if not.
The name "proton cannon" was somewhat of a misnomer. A beam of nothing but protons would carry such a strong electrostatic charge that its own self-repulsion would spread the beam out a hundred meters wide in a microsecond. Instead, an equal number of electrons were mixed back in at the last instant, just before the beam left its muzzle. The resulting proton/electron bolt was, technically, an electrically neutral plasma; though at its relativistic muzzle velocity, calling it a "plasma weapon" hardly did it justice. Even at low power, a single "proton" burst could punch through a missile's thin casing and scramble its electronics, if it hit close to dead center. Firing such a proton burst also required the ejection of a lot less material than, say, a slug launcher or point-defense gun with the same kinetic energy — a vital concern when you had to carry every gram of mass onboard with you. Still making 100g evasive maneuvers, the fighter's S.I. trained a proton cannon on each incoming blip, and let loose in low-power rapid-burst mode. One by one, each missile's tracking failed, turning it into an unguided slug.
Not that an unguided slug wasn't still a danger. At 20 permil relative, a half-tonne impactor would do more damage than a thermonuclear bomb. But now, the chance of an impact was too remote to worry about. Each dead missile flashed past harmlessly on its way out of the Solar system.
The first Sol fighter itself would be tougher. It could unleash several of its weapons all at once, all timed to arrive at the instant it rushed past. Gellimand 3 would need a healthy dose of luck and defensive posturing to survive the encounter. Its S.I. throttled the engine back to idle, and counted down the minutes as its first attacker approached.
At one minute, with the Sol fighter a scant 270 000 kilometers away, Gellimand 3's engine flared back into life at its full 100g as it resumed evasive maneuvers. Sol's aresenal boasted few, if any, charged particle weapons — their top brass favored the punch of kinetics — but just to be on the safe side, Gellimand 3 also fed power into its superconducting magnets, surrounding its armored cylindrical shell with a magnetic field strong enough to capture an incoming charged particle or plasma burst and hurl it harmlessly aside.
Zelta Cee was expecting all this. At such close range, the light-speed delay between one side's action and the other side noticing the action was less than a second; the dynamic had shifted from a pondering chess game to a lightning-quick fencing match. Zelta Cee, though, had brought along a kind of main-gauche to supplement the epée of its conventional arsenal. Like its younger sister Dee, Zelta Cee also sported an experimental piece of hardware, though not one as game-changing as the former's Directional Screen. It carried a bulky honeycomb of grazing-incidence mirrors embedded in a recessed cavity in its armor, known simply as the Radiation Gun. A tiny puff of antimatter was fed into the core and annihilated, and the myriad mirrors focused the resulting gamma rays until they converged to a spotlight-like beam. If Zelta Cee were lucky, the gamma rays would knock scads of electrons loose from the target's armor, and its "protective" magnetic field would turn the particle shower into an electromagnetic pulse inside its own circuitry.
But the Radiation Gun would only get one shot in this battle. By the time it recharged, the intruder would be far behind Zelta Cee and dwindling into the unapproachable distance. Best to wait until the moment of closest approach. In the meantime, it was time to let loose with short-range missiles.
Gellimand 3's thermal sensors caught all six launches. Its proton cannons once again erupted in burst after low-power burst, hoping to wreck the tracking of these short-range threats the way they'd done for the cruise missiles. It wouldn't be able to keep this up for long; though proton cannons consumed no "ammunition," they required current pulses so intense they could only be provided by battle capacitors, and those took over a minute to fully recharge. Proton cannons were also notoriously inefficient, which meant they got hot. A fighter could only dump heat into its exhaust so fast. Gellimand 3 watched the engines die one-by-one on four of the six bandits before overheating shut two of its proton cannons down. The remaining cannons finished off the fifth missile, and finally the last, with barely a coulomb left to spare in the capacitors.
And at that moment, Zelta Cee was upon it.
As the Sol fighter passed within ten thousand kilometers of its Alpha-Centaurian target — close enough for a wrestling bout or a slow-dance — Gellimand 3's high-energy photon counters registered an intense gamma ray spike coming from its attacker's direction. Nuclear ordnance? No, the frequency range was too narrow; it had to be antimatter. Odd, the thermal sensors and radar had detected no launches. Had antimatter ordnance detonated on its attacker's hull? Or in it? The Sol fighter's engine was still on full, correcting its course as though a thinking mind were behind it. If an antimatter explosion had gone off inside it, neither its engine nor its S.I. was affected. Whatever had happened, Gellimand 3 had just taken a big gamma ray jolt, strong enough to induce electrical currents in its armor. This would have been enough to fry its microcircuitry . . . but as luck would have it, the brunt of the burst landed on its nose. It was carrying a lot of iron in its nose, which shielded its innards just enough.
There was more iron in Gellimand 3's nose than any normal fighter would have any use for, in fact. But the S.I. would save that for later.
As the attacker shot past, fast enough to cross a continent every second, another missile barrage followed. At this range, there was no time to knock out their guidance; Gellimand 3 could only hope to dodge. It pointed its nose as far away from the missiles' all-too-short trajectory as it could, and hoped that those launches had been intended for a target disoriented by the gamma ray burst. They were. Imbued with their launch platform's own dizzying speed, the missiles needed the full thrust of their own engines just to rendezvous with their target's predicted location. Gellimand 3's last-instant engine burn had pushed it out of the range of all of them . . . save one. The last missile nicked the rear quarter at a shallow angle, turning itself and two layers of armor into incandescent vapor that spalled sideways and, briefly, glittered in the dark. Gellimand 3 now had a furrow three meters wide dug into its flank, but that was it. It had escaped the encounter virtually unharmed.
As Zelta Cee's S.I. watched its target hurtle past, still functional and dangerous, it only knew that the Radiation Gun didn't score a kill. It would be chalked up as yet another failed field test of yet another experimental weapon. Zelta Cee throttled its main engine up to a low-powered cruise acceleration of 2g, and lumbered toward home defeated.
The intruder could now turn its attention to the other fighter, due to arrive in another forty minutes or so. There would be no dodging of a single fast pass with this one. It was braking, and would be able to rendezvous regardless of how hard Gellimand 3 did, or didn't, accelerate. It would have all the time it needed to fire weapons until its target was dead. There would be no running. The only way Gellimand 3 could survive the coming encounter would be to kill its attacker first.
Zelta Dee slowed — or rather, accelerated — until the gap between itself and the intruder converged at the snail's pace of a single permil, a mere 300 kilometers per second. In all that time, the intruder had launched no cruise missiles at it. It must have known that avoiding a fight with Zelta Dee was impossible long before now, so either the Centaurian fighter was saving its ammo or its mission package didn't include any cruise missiles to begin with. Now, the range was coming up on the two hundred thousand kilometer mark, the knife-fighting point-plank range needed for both sides' short-range weapons.
Gellimand 3 carried no fragmentation missiles. These were only useful against an unarmored spacecraft that might be able to dodge a projectile as it closed in; neither the Sol fighters it would have to blast its way through, nor its ultimate target, fit that description. Against the 60-meter-wide cylinder closing on it, only a missile that stayed in one piece 'til the instant of impact would have a chance of punching through all those layers of whipple armor. Gellimand 3's S.I. selected three short-range kinetic missiles from its arsenal and belched them forth.
With less than a light-second between itself and its target, Zelta Dee spotted the launches almost the moment they happened. Instantly, its point-defense batteries flowered to life, locking on to each incoming radar blip and spitting out hypervelocity slugs, each no bigger than a housefly. Two of the three Centaurian missiles met with one of these tiny metal darts and went dark, their dead guidance hardware dooming them to the last course-correction they'd applied. The third, though, managed to slalom through the hail of projectiles and correct for Zelta Dee's erratic jinking sufficiently to drive itself home. In the brief instant before impact, Dee's S.I. concluded that it wouldn't be able to get out of the way. It focused its Directional Screen on the incoming ordnance and poured power into it from its battle capacitors.
And, apparently, this was sufficient. The multimegatesla megnetic field projected before Zelta Dee shoved just hard enough on the missile to nudge it off course, and turn a solid hit into a miss.
Gellimand 3's S.I. tried to digest this odd bit of data. Kinetic missile number two followed a perfect track for a direct hit, yet there was no sign of impact. The enemy fighter's engine continued to burn at 100g thrust level, and its thrust vector continued to gyrate exactly the way a fighter performing evasive maneuvers would. The enemy was still intact, and could decide to shoot back at any time. It might even be immune to kinetic missiles. This was bad. It was time to haul out the secret weapon.
Zelta Dee dumped the heat from that last capacitor discharge into its exhaust stream while its capacitors recharged, and ran through its firing options. There was still enough power in the capacitors for its slug launchers or a couple of its proton cannons; in some seconds the capacitors would be charged enough for a full proton spread. It could hammer the target with short-range missiles in the meantime, though the supply of those was harshly limited; even Zelta, its carrier a hundred million klicks behind it, only had enough missiles onboard to restock each of its fighters once. But . . . what was that new thermal anomaly on the target's nose? It showed a classic blackbody curve peaking at 970 nm; that would make it white-hot, nearly 3000 Kelvins. The target was dumping a lot of heat into something other than its exhaust. And —
Slug launch detection! Something just erupted from the target toward Zelta Dee, going much faster than the target itself. It was the thermal anomaly; the white-hot blip on the target's hull was now a white-hot kinetic slug, hurtling toward Dee at fifteen permil relative. It was distant enough, though, that Dee's continued evasive maneuvering should easily put the fighter out of harm's way. Except . . . was it maneuvering somehow? Impossible. No electronic guidance system could withstand the multimegagee slam of even the gentlest slug launch. But . . . there it was, its encroaching profile unmoving against the background stars, altering its course to match Dee's every bob and weave. Zelta Dee's S.I. reclassified it as a high-speed missile, and opened fire with its point-defense guns. The hail of point-defense fire registered direct hit after direct hit, but . . . the white-hot missile didn't stop tracking! At last, unable to kill the threat or get out of its way, Zelta Dee pointed its Directional Screen straight at it, applied every watt of power the screen could withstand, and hoped for the best.
And, per standard procedure when faced with an unknown, the S.I. beamed all the data it had on this strange weapon back to its carrier, six light-minutes away.
As the hot threat crossed the last 4500 kilometers — the final second of its terminal flight path — Zelta Dee's S.I. carefully monitored the Directional Screen. The wattage now being fed into it was right at the bleeding edge of its design limits. Were it an established technology that had been stress tested under repeated worst-case conditions, being at the top end of its power envelope wouldn't be an issue; but this was a prototype, and it was a terrible risk to push it this hard. The S.I. focused its full attention on every telltale sensor attached to the Screen, ready to reduce power the instant any value started to deviate. None of them did . . . but right in the last few milliseconds, to the S.I.'s great alarm, the Screen was pivoting so as to face a different direction! It had to be brought back on track, and fast. What had caused — why was it pointed at the enemy fighter, and not at the —
A fighter's S.I., like a human's brain, was built in layers. The topmost cognitive layer made the command decisions, while a couple dozen unintelligent layers sitting below it ran those autonomous functions that needed digital attention. To minimize its response time, the aiming of the Directional Screen was under the command of one such low-level layer. Gellimand 3, as it turned out, had decided to supplement its attack by firing three proton bursts timed to reach the target near the moment of impact, and one of them had arrived a little early. It had been a better decision for Gellimand 3 than it knew — for, with all the evasive maneuvering the secret weapon had been tracking its target through, the proton bursts arrived at their target from a different angle than the secret weapon did. The low-level autonomous layer controlling Zelta Dee's Directional Screen received sensor data telling it that a proton burst from the enemy fighter's direction had just whizzed by, dangerously close to the hull. Proton bursts were a known and understood threat; the white-hot something closing in was an unknown. So, it swung the Directional Screen to face the enemy fighter from whence the proton burst had come.
It was a software glitch. It would probably be ironed out in the next iteration.
For a split-second, Zelta Dee knew it was doomed. It had kept its comm laser pointed toward its distant carrier throughout the battle, sending constant updates of its position, the target's position, detector readings, decisions made, and decisions not made — all for the benefit of its human masters. Once, when it had had the time and bandwidth to spare, it had sent its wide-eyed, almost poetic musings on the way the starlight danced in its detectors while its hundred thousand tonne metal body gyrated in evasive maneuvers. Now, it packed as much data as it could about this last blunder, this fatal flaw in its screen's software, into the few bits it had time to transmit.
And as it sang its swansong into the void, watching helplessly while its screen override took hold too late, the white-hot missile struck home.
The impact happened faster than any accelerometers could register it. Armor failure sensors blared their cascading alarms for a few brief microseconds; then the fighter's electronic brains and guts, buried deeply in its core, failed faster than they could assess what was happening — until at last there was no S.I. to do the assessing.
A little over a hundred million kilometers away, and six minutes in the future, the last ultraviolet gasps of Zelta Dee reached its carrier. Captain Ganges watched in horror as the last instants of the battle were recreated before her eyes. She rubbed her face for a second to clear her focus. "Colonel! Zelta Dee's gone dark!"
"It lost the fight?!" Colonel Yindras scowled, moving to the Remote Ops station to see for himself. He would have stomped there in his most onerous march, but Zelta was idling now with its engine off, and it was hard to move angrily in microgravity.
"The Centaurian fighter's got some kind of new weapon," Ganges continued. "Details are sketchy at this point, but from its behavior, it . . . well, I'd call it a homing slug."
"Impossible," the Colonel quipped as he stared over her shoulder at her display.
"Rrrrmmm," Ganges scanned the data again, "Well, there wasn't a lot of data Zelta Dee could send us. Maybe I'm misinterpreting some of it. Maybe the slug launch detection was a mistake, and there was really a missile cruising along the same course as the fighter but going fifteen permil. But then Dee should have picked it up a lot earlier, especially with how bright it was in the near-infrared."
"Are you sure it was homing?" the Colonel asked.
"Positive. A blip doesn't stay put at the same angles, unless its changing course to track you while it closes in."
"Or unless it's stationary," Colonel Yindras pointed out.
Captain Ganges shook her head. "You're thinking of the target picture from a non-moving platform, sir. If your platform's making evasive maneuvers, like Zelta Dee was, it'll makes even a stationary target appear to move, unless it's really far away." She snorted. "And even if it didn't, that's the hardest hitting 'stationary' object I've ever seen, then."
Yindras frowned. "All right." He turned to a sergeant. "Nguen, tell Cape Jovial the bad news, that our target is still live and inbound."
"Yes sir," Sergeant Nguen acknowledged, and started recording the necessary comm packet.
The colonel turned back to his remote ops officer: "Do Aay and Bee have enough running room to do a rendezvous intercept?"
Ganges furrowed her brow. "One-oh-eight million klicks, intruder's inbound at fifteen permil relative . . . so yes. At 100g, our fighters would need only about 10 million klicks to match that speed. But since the target's coming toward us, Aay and Bee would have to accelerate away from the target and toward Station Jove, and ol' Cape Jovial's barely one million klicks behind us. If we want the rendezvous to happen before the enemy reaches Station Jove, they'll have to accelerate toward the enemy first, then bleed off all that speed — the delta-vee is going to be huge. They'll barely have enough juice to brake to a stop afterward, let alone return to us."
"So we'll have to pick them up afterward," Yindras nodded. "Still better than letting the intruder through."
"Unless the intruder decides to accelerate even more, after our fighters reach their intercept speed," Ganges reminded him. "Then, a rendezvous will deplete their fuel so badly they won't be able to stop. They'll keep coasting right out of the solar system, unless we order them to crash into Jupiter. And the enemy knows what the delta-vee budget of our fighters is."
The colonel winced. If they'd sent Aay and Bee earlier, they'd have enough of a lead that they wouldn't need to accelerate toward the intruder before turning back the way they came to match speeds. He'd dutifully followed the tactical doctrine of holding fighters in reserve 'til you knew they'd be needed — and look at where that had gotten them. They couldn't even guarantee a rendezvous with the enemy now. The best they might be able to hope for was two high-speed passes — both of which could end up missing the target, just like Zelta Cee had done.
Back at Station Jove, the Brigadier General fumed. "They've got to be kidding! A single xorn fighter got past both our Gate Guard and two of our own fighters?!"
"Looks that way, sir," the young Lieutenant answered. "They're claiming it has some kind of new weapon."
"Did they give details?" the General growled.
"They're saying it's a —" the Lieutenant did a double-take "— a missile fired from a slug launcher."
The General seemed genuinely alarmed. "Good lord. Samuels!"
"Yes sir?" barked a startled Major floating at the main weapons station. He quickly hooked his feet through the securing footholds.
"Did Sol develop any contingency tactics, in case an enemy invented a missile that could be launched at slug speed?"
"Uh . . ." Major Samuels nervously paged through one information lookup after another. "I'm not seeing any . . . I'll have to check the archives; they're not easy to search. They might've called the contingency something obscure, that wouldn't show up if I searched for obvious terms."
"Well, get on it. If the intruder's luck holds out, we're going to need it. Let's hope Zelta's other two fighters can do some good."
Gellimand 3's S.I. expected the enemy to repond by sending more fighters toward it, so it came as no surprise when the two engine telltales arrived at its detectors six minutes later. In that time, it had already closed the gap to its ultimate target by another 1.6 million kilometers. The two new thermal sources accelerating toward it at 100g were doubtlessly fighters, apparently launched by the same deployer that had launched the first two adversaries. But if Gellimand 3 accelerated now, it could avoid a rendezvous entirely before it got within close weapon range of Jupiter . . . unless Sol had invented some new kind of fuel-heavy fighter with a higher-than-normal delta-v budget, or was willing to sacrifice its fighters to a burnout trajectory that sent them into interstellar space. The higher speed might also make targeting more difficult. And, of course, it would put Gellimand 3 at the midway point of its own delta-v budget; it was already closing with its target at fifteen permil, and after accelerating to twenty permil it would take all of its remaining fuel just to nullify that speed. Return would be impossible. No matter, the S.I. really hadn't counted on surviving the mission anyway. It was worth the risk. Gellimand 3 pointed its nose straight at its destination and fired up its main engine again, pouring on the acceleration.
Even though the intruder's engine was pointed away from Zelta Aay and Zelta Bee, the glow of hot helium jetting out behind it was unmistakable. There was nothing the two Sol fighters could do about it. Any chance of a rendezvous vanished the moment that engine-flame registered on their detectors; by now the enemy would have been barrelling toward them at full thrust for the 6 minutes its engine-flame light had taken to reach them. The two Zelta fighters resigned themselves to a single high-speed pass each. They shut down their engines — they were already pulling away from their carrier at 2.4 permil, no reason to waste more fuel — and ran through their remaining options.
Assuming their target shut off its engines after 5 permil of extra acceleration, they'd meet in a hair over four-and-a-half hours. Their carrier would be 11.5 million kilometers behind them, and Station Jove — whose defense was their number one priority — would be only a million kilometers behind that. If Zelta Aay and Zelta Bee both missed, the Station's remaining defenders would have only half an hour before the enemy reached them. Ramming was unlikely — something in the fleet was bound to knock out its maneuver capability in that last half hour — but it wasn't impossible. If the Alpha-Centaurian fighter somehow made it through and lucked out on its course targeting, its impact kinetic energy would be equal to 33 tonnes of matter and antimatter. In the more likely event that the enemy was knocked out before it could ram, the worst the defenders would have to contend with was a volley of high-relative-velocity weapons fire . . . similar to what Zelta Aay and Bee intended to throw at the intruder themselves.
They could try and ram the enemy on their one high-speed pass, which would completely disintegrate all parties involved if successful, but the enemy's own 100g engine made it every bit as maneuverable as themselves. If they homed in on it, it would get out of their way just as fast. But in trying to ram, even if they failed, they might get close enough for a barrage of kinetic slugs to secure a few lucky hits.
They waited.
Captain Ganges stared at her report screen in stunned disbelief. Then, she pinched the bridge of her nose and winced. Nearly five hours of waiting, for this?! "The encounter reports from Zeltas Aay and Bee are in, sir. The target . . . remains active."
Colonel Yindras buried his face in his hands.
"They managed to score a few grazing hits with their slug guns on the way by," Ganges explained, "But that was it."
"So a few gashes in its armor, but otherwise the enemy is still inbound?"
Ganges breathed a heavy sigh. "Yes."
The Colonel was silent for a long moment. Then: "Well . . . we'd better go pick up our fighters." He grimaced, then sneered. "We'll need them to defend what's left of Station Jove after the intruder's done with it."
A million kilometers behind Zelta, the Brigadier General reacted nearly the same way. "They didn't kill it," he announced to everyone in the room. "We've got a live intruder just half an hour away." He addressed his young curly-haired sergeant: "Put Station Jove on condition red."
The station's docked fleet had been at condition yellow for over a full day. Now, weary from their heightened vigilance, the second stage alert klaxons blared in the crews' ears. Taking turns in orderly coordination with the station's traffic controllers, each craft that was still spaceworthy undocked itself, moving far enough away from the station that it could run or fight at an instant's notice when the attacker arrived.
"Do we still have the five other carriers from yesterday?" the General asked.
Major Ragaji checked the blips at the tactical board, then confirmed: "We've got four, sir. Callistra got ordered to the Sirius hyper hole while you were off duty."
"Tell them all to deploy," the General commanded. "Station Jove's thrusters can move us out of the way of any impactor, but not if the threat can home in on us. We need that xorn fighter neutralized!"
"Yes, sir!" Ragaji replied. He tapped each of the four carrier-colored blips clustered near the station on his panel, sending dispatch packets to each of them. Then just to be sure they understood, he picked up the microphone and keyed an omnidirectional broadcast: "Attention Ghanima, Domya, Fulgra, and Diana. All four of you are to attack and destroy the intruder. This is a coordinated attack, so be sure your fighter groups don't step on each other. Under no circumstances is the intruder to be alive within short weapons range of Station Jove."
Ragaji glanced at his external displays. He didn't need magnification; 600 meters of polished metal armor would have been hard to miss even outside the Station's hazard zone, and they wouldn't be that far away for another five minutes. Four behemoths rose (or fell?) away on columns of invisible helium exhaust. And in the distance ahead of them, barely visible against the darkness, a tiny speck of blue-white light winked out. That would be the dying embers of the intruder's hot-fusion engine as it throttled back to idle. The Major's teeth clenched. That 100g flame had pushed the invader toward their doorstep a day ago. The last light must have been left over from its evasive maneuvers, when it somehow dodged every missile and slug that two whole fighters had thrown at it.
Gellimand 3's S.I. saw the expected flurry of activity forty seconds later. Four enemy fighter-deployers were on the move. That meant at least twelve, and as many as twenty-four, fighters would be upon it soon. Jupiter's big space station was probably throwing every military spacecraft it had into Gellimand 3's path. Even with its speed advantage, survival was now impossible. All that mattered was getting within weapons range. Short weapons range would be preferred, but there was no chance the defenders would allow that to happen. Its last act would have to happen from over a million kilometers out.
Five minutes later and 1.8 million kilometers closer, seventeen tiny ringlets of blue-white light added their glow to the oncoming vista. Those would be the engine telltales from the Sol fighters, just launched, as they thrusted directly toward Gellimand 3 at 100g. They could have launched cruise missiles, but there would be little point; the homing electronics and other fragile systems on a cruise missile imposed the same 100g acceleration limit as on a fighter, and for exactly the same reason. If the 17 new targets kept accelerating, and there was no reason to assume they wouldn't, they'd meet Gellimand 3 in about 25 minutes, 1.1 million kilometers away from the ultimate target.
Not optimal firing range, but close enough.
Gellimand 3 waited, for the last time.
Seventeen fighters, arranged in four flights per the carriers they'd launched from, arrived right on schedule. Seventeen hundred-thousand-tonne steel juggernauts, carrying more than that mass in unspent fuel, all faced down a like-sized intruder they had to kill. They now stood toe-to-toe with Gellimand 3, a mere three hundred thousand kilometers away from it. The kinetic slugs, short range missiles, and particle beams and lasers (if any) would start flying from those defenders any second. Gellimand 3 spooled up its main engine one last time, but it didn't go into evasive gyrations. It needed a stable launching platform. After it had fired its nose launcher a little over 5 hours ago, it had loaded a second round and begun heating it. Now, it pointed its nose directly at the space station 1.1 million kilometers away, and opened the nose bay door. One last check of the field integrity on board the slug, the "programmed" target selection, and the charge state of the capacitors, and . . . launch! The giant slug launcher buried in Gellimand 3's nose heaved its cargo forward at millions of g, jerking the whole fighter backward as its mountings strained against the kick.
For the second time since it arrived in Sol space, a slug from Gellimand 3's experimental Liquid Metal Gun was on its way.
Standard tactical doctrine at this point called for Gellimand 3 to commence evasive maneuvers, in the slim hope of dodging the incoming fire from its attackers. But against the massed fire of 17 onrushing fighters, the odds of survival were just too low. Instead, it nudged its course until it hurtled directly toward the same station that was its Liquid Metal Gun's target — or, rather, at the orbital position the station would occupy when Gellimand 3's remains arrived. If any of those incoming fighters were sporting a magnetic snare, it would certainly try to knock Gellimand 3 off course; but if not, and if for whatever reason Station Jove didn't get out of the way, well over a hundred thousand tonnes of steel and fuel would hit the station at two percent of light speed.
In concert, the seventeen Sol fighters throttled way back from their 100g intercept cruise, and every short-range missile they carried erupted from its silo. The tiny blue-white flames of their miniature hot-fusion engines overwhelmed Gellimand 3's thermal sensors with more targets than it could track. It was an unnecessary overkill. Gellimand 3 didn't even try to get out of the way. Its point-defense proton cannons lay still; there was no point in knocking out the missiles' guidance systems if no evasive maneuvers were in the works. The first missile struck dead center on one side, slamming through sixty meters of spacecraft and emerging out the far side hardly slower than when it entered. The tiny portion of its speed that had been robbed during the impact, though, represented as much energy as a small nuke. The internal shockwave propagated through the megapressurized liquid-metallic hydrogen and deuterium in both of Gellimand 3's enormous internal fuel tanks, bursting fuel lines and crushing most of the engine assembly. A wide blast of molten and vaporized steel erupted from the gaping exit wound, then liquid fuel from the internal tanks gushed out faster than it could evaporate. Cruelly, the cone-shaped impact wave missed the S.I.'s central brain, forcing the doomed fighter to watch as a second and a third missile tore through and left it progressively more gutted. Finally, the fourth missile delivered the coup de grace, and Gellimand 3 went from semi-intelligent weapons platform to small metallic asteroid.
The remaining missiles continued to batter away at the lifeless hulk, turning it into an ever-more-ragged cloud of hot shrapnel.
There was nothing the Sol fighters could do, though, about the tiny white-hot molten streak speeding away behind them toward Station Jove.
"That's a kill," Major Ragaji reported from the tactical board.
"About time," the Brigadier General grunted. "Did the fighters nudge the hulk onto a safe trajectory?"
"Yes sir," Ragaji studied his board, "But ... uh oh. Sir? I think the intruder managed to squeeze off a round from that slug missile launcher of theirs. We've got an unidentified blip pulling ahead of the intruder's debris cloud, headed straight for us at . . . good lord, at thirty-five permil relative! That puts its E.T.E. at only one and three-quarter minutes."
"Samuels?" the Brigadier General addressed his main weapons station with trepidation.
Major Samuels breathed a few nervous gasps. "No dice, I couldn't find any contingency plans for high-speed missile launches. Guess we'll just have to hammer at it with point defense like any other missile, and try to move out of the way as best we can." Inwardly, Samuels wished he were wearing a space suit. Even a standard-sized slug could tear a hole in their compartment big enough to let all the air out, and that monster projectile bearing down on them was a hell of a lot bigger than a standard slug. But those damned compression suits squeezed so hard around their wearer's hands as to make even typing an uphill chore, and Sol's military long ago decided that the lost utility wasn't worth the added margin of decompression safety. Of course, the people that had made that decision were back on Earth's surface, shielded safely below a miles-thick layer of omnipresent air that was never in any danger of draining away into space.
"All right then," the Brigadier General declared. "Samuels, lock our P.D. cannons on the target and fire the instant it's in short weapons range. Tactical, spool us up and put us on evasive, do everything you can to move us out of its path. Sergeant," he turned to the curly-haired North Martian youth, "Sound evasive alert!"
"Yes sir!" Sergeant Li snapped crisply, strapping herself to her station and hitting a new klaxon as she keyed her mike. "All personnel, thrusters engaging! Random thrust in five seconds!"
Spanning the entire orbiting framework that was Station Jove, a network of electric arc-jets blossomed to life, throwing propellant first in one direction, then another. Their combined thrust amounted to less than a tenth of a gee, but it was enough to get the station moving.
Now secured to the tactical station with foot and torso straps, Major Ragaji watched the display and shook his head. "Just like their reports said, sir. The object's correcting course and homing in on us."
Samuels furrowed his brow. "Sir? The object's white-hot, but I'm seeing spectral lines in its blackbody curve. It's . . . it's iron! The whole thing's a big chunk of iron!"
The Brigadier General's face brightened. "So you can grab it with a magnetic snare!"
"Uh, no, sir," Samuels gulped. "At that temperature, iron's not ferromagnetic."
The General grumbled, "So our magnetic protection field won't help us either?"
"'Fraid not, sir," Samuels shook his head.
"Well . . . maybe it's got a solid core or something," the General fluttered. "Maybe its tail end is cooler. At least try, dammit!"
Samuels inhaled sharply. "Will do, sir. It'll be in close weapons range in thirty-two seconds."
The General snapped his fingers. "Missiles!"
Samuels looked hard at his displays. Could their short-range missiles lock onto something that small? It was certainly a bright enough thermal target, and he doubted it could do much in the way of evasive maneuvering. He selected the target, tripped the firing safety, and pressed the buttons. Somewhere on the other side of Station Jove, two magnetic launch tubes gently nudged their cargoes clear of the station — "gentle" being a relative term for the 100g imparted to the two missiles — and four-and-a-half seconds later, two tiny proton-deuteron rocket-motors lit off. "Missiles away! The target'll only be a few seconds away by the time they hit, sir. We'll try our luck with point defense and snares in the meanwhile."
He watched the distance plummet, like a skydiver whose parachute wouldn't open.
"Firing!" Samuels barked. Instantly, the tiny hypervelocity guns bristling the Station's hull began spitting out their miniature slugs, all trained on the small but bright target now only 300 000 kilometers away. The rod of molten iron had cooled a bit in the minute-or-so since its launch, and now glowed only a dull yellow-white hot, but it was still intensely bright in the infrared; only the rocket motors of their outrushing missiles were brighter. The point-defense guns had no trouble pinpointing the target, leading it just the right amount — Samuels had been right, the Liquid Metal gunbolt had neither the ability nor the inkling to dodge incoming fire — and as such the station's point-defense guns scored their longest-ranged direct hits on record.
But the molten intruder kept tracking them.
"How?!" Samuels' hands shook. "Those were solid hits! How could it still be homing in on us?!"
"It's molten iron," Ragaji offered. "There's nothing inside it for your slugs to wreck. They're probably just splashing right on through."
"Dammit!" Samuels muttered. "Lasers!" He flipped a few more controls, and gigawatts of coherent power lanced invisibly through space to meet the threat, now barely more than 200 000 kilometers away. The distant glow brightened, the peak blackbody frequency shifted higher, but —
"It's still correcting course!" Ragaji reported.
"The lasers only made it hotter," Samuels shook his head. "Closer to its temperature when we first detected it."
"If you heat it all the way to a vapor, would that knock it out?"
"Our lasers would overheat before we could pump that much radiation into it," Samuels answered. He glanced at his targeting display. "Coming up on snare range . . ." He checked the magnetic snare's status, and the target. "Whoa!"
"Hm?"
"There's a magnetic anomaly reading coming from the slug! I didn't notice 'til our snare locked on target just now. That's how the slug's tracking us! It's a magnetic lock! It's got us in a really long, steady magnetic snare!"
"How's that even possible? You said it was too hot to be ferromagnetic."
"You don't need to be magnetic to generate a snare. But that's the longest damn snare I've ever seen. Probably too weak at extreme range for our detectors, which is why our snare alarm didn't go off. Let's see how it likes a dose of its own medicine. Snare 3 firing!"
A multimegatesla magnetic jolt surged outward from one of the Station's emitters and, a third of a second later, passed over and around the liquid iron bolt like a gentle breeze.
". . . Was that a hit?" Major Ragaji puzzled, staring at the tactical board.
Samuels checked the return signal. "Yes."
"Then it's no good. It's still tracking us."
Sergeant Li heard this last piece of bad news, then looked at the time and distance remaining. Gasping, she keyed her mike. "All personnel, brace for impact!"
Samuels nervously bit his finger. "It'll hit our missiles half a second before it gets here. Can the thrusters get us out of the way in time?"
Ragaji watched the blip fly ever closer. "If your missiles knock out its tracking."
A scant five thousand kilometers away — the last half-second of the slug's journey — solid steel met molten iron. The liquid metal splashed and flowed around the first projectile, reforming itself on the other side as though nothing had happened. The second missile likewise passed right through its target, its speed hardly changed at all. Had they posessed explosive warheads that detonated on impact, they might have been able to blow the gunbolt apart from the inside and disrupt its magnetic lock; even its Centaurian designers weren't sure. But these were the kinetic missiles that Sol had come to rely on so well for their anti-spacecraft arsenal. They relied on speed, and speed alone, to hit the enemy hard enough to break its back. A molten target simply didn't have a back to break.
There wasn't enough time to tell that the missiles had failed. Station impact happened first.
At thirty-five permil — 10 500 kilometers per second — it didn't matter that the impactor was molten. A solid iron battering ram or a blast of iron vapor would have had the same effect. The midsection holding the station together disintegrated, its armor pushed aside faster than the metal could even crumple. As the slug slammed deeper into the station's support structures, it slowed, and the lost kinetic energy became heat. Metal, ceramic, and organics all turned to liquid, then vapor, then plasma, as the impact spalled out the far side.
Station Jove was cut cleanly in half.
The station's thrusters ceased instantly as the jolt whipped through both halves of Cape Jovial. Sergeant Li lost her grip on her station and rotated backward as the floor — or was this the wall? — flew up to meet her. She yanked herself back into position and read the monitor. "We've lost data feed from sections 54 onward! Switching to internal radio comm."
"Damage report!" the Brigadier General barked.
"Sections 54 through 65 are dark," Sergeant Li read from her display. "Sections 50, 51, 68, and 70 are completely breached, reading vacuum." She winced at the thought of any crew who were in those sections when they blew open. "Some nearby sections show pressure leaks; looks like patch crews've been notified." She gasped slightly as she read: "The whole block from section 100 through 125 is on emergency power." Sergeant Duane Yu, the boyfriend who'd followed her here from North Mars, was usually stationed in section 116, right in the middle of that block.
The General turned to his other staff. "How's our ops status?"
"Tactical's still up, sir," Ragaji told him.
"Thrusters are out," Samuels reported, "Both halves."
"Section 84's reporting electrical failure," Li continued. Section 84 was one big QC&C reactor, responsible for powering a large chunk of the station. "The impact must've caused a feedback surge."
As the Brigadier General absorbed the damage reports one by one, his head reeled. This was bad, and not just for Station Jove. The Centaurians had managed to build a guidance system that could survive the girder-crushing acceleration of a mass driver launch, and which couldn't be shot down by point-defense systems. A guided kinetic slug. How could any Sol fleet possibly stand up to an enemy so armed?
"Uh ... sir?" Ragaji broke in. "We've got another problem. Our fighters did a little too well on the intruder."
"Hm?" the General grunted.
"It put itself on a collision course with us just before we killed it," the Major explained. "The main bulk of it's been safed, nudged off course so it'll miss us — but our fighters' weapons must have blasted away some pretty significant chunks of it. There's a cloud of expanding debris racing alongside its original collision trajectory at the same 20 permil relative, and we're in its way."
"And we don't have thrusters?!" the General turned to Samuels in alarm.
"N-n-no, sir!" Samuels was at the brink of panic.
"Forty-five seconds 'til the shrapnel arrives," Ragaji noted.
"Are any of our snares still working?" the General asked.
Samuels scanned his readouts, hands shaking uncontrollably, then stammered, "We've got three undamaged, but none of 'em have power."
The General snorted. "Options!"
"Uh ..." Samuels tried desperately to regain his cool, scanning his panels for anything they could use. "Field!" He switched on the station's magnetic field, the same charged-particle protection every fighter and carrier sported. "Field's still working!"
The General growled, "That'll only deflect the little sand-grain-sized pieces. What can we do about the bigger chunks? And the non-ferrous debris?"
"Uh oh," Samuels continued. "The field's only up on our half. The e-mags on the other half of the station aren't responding."
The General exhaled sharply. He turned to Sergeant Li, and there was a thin note of terror in his eyes. "Sergeant . . . order the crew to minimum cross-section."
Sergeant Li's eyes bugged wide. She knew what it meant. More of the crew would be dead very soon. Hand shaking, she grabbed her mike and keyed it. "All personnel, minimum cross-section. High-speed shrapnel impact is imminent. Straighten your body with your head or your feet pointing right at Jupiter."
"Twenty seconds," Ragaji intoned, swinging his torso around while holding onto the tactical station's handles. There was no protective gear to don, no crash station to brace against. Nothing onboard was anywhere near thick enough to stop a 20 permil fragment. If his body happened to lie along the path of one of those speeding bullets, he wouldn't live long enough to notice.
"Ten seconds." The countdown seemed to last an eternity.
. . . Impact.
It was like a shotgun blast. One instant, all was intact; the next, every section of Station Jove was riddled with punch-holes. Automatic alarms blared as air hissed out through legions of tiny hull breaches. The other half of the station had it far worse. With no magnetic deflection field to protect it, the high-numbered sections of Station Jove bore the full brunt of the countless microfragment grains filling the debris cloud. Some sections were hit lightly enough that their whipple shields could absorb all the energy; others turned into a grotesque charicature of Swiss cheese; still others simply disintegrated.
The main mass of the enemy hulk, one hundred sixty-four thousand tonnes of metal and now-gaseous fuel, passed harmlessly by and slammed into Jupiter. At the point of Jovian impact, a tiny pinpoint of light erupted. It spread, and as it spread it darkened, until an enormous black disc of cratered Jovian atmosphere the size of Mercury bruised the surface.
A few hours later, the winds of Jupiter had erased this blemish from the planet's face, as though nothing had happened.