Center of Gravity

by Ian Douglas

  “We will be launching for CSP only.”

  “All combat squadrons are ready for launch, Admiral.”

  “You may commence launching the first three. We’ll hold on the rest until we need them.” And we will. . .

  CSP—Combat Space Patrol, the modern analogue to flying CAP over the fleets of old-time oceanic navies—required that fighters fly in fairly close formation with the carrier and other vessels of the battlegroup, rather than accelerating to near-c for a long-range strike hours in advance of the capital ships. At five hundred gravities, the alien objective was just over ten hours away. If he ordered a long-range high-G fighter strike, the fighters would reach the objective in sixty-five minutes. He would keep that open as an option, but Koenig wasn’t going to exercise it until and unless he needed to. Fighters operating on their own for more than six hours before the rest of the CBG arrived faced annihilation.

  He stared up at the overhead display, wondering what that bracketed point of light against the disk might be. Fortress? Warship? Asteroid base? Supply depot on an unimaginable scale?

  The tactics he decided upon—and the chances of survival for the next few hours, both for the fighter wing and the battlegroup, depended upon the answer.

  “CAG? I want a flyby of Al–01. Bring Commander Peak into this, will you?”

  “Aye, sir.”

  They needed to know what they were facing in there.

  Drop Bay 2, TC/USNA CVS America

  Outer Reaches, Alphekka System

  1114 hours, TFT

  “Pilots. Man your fighters!”

  Gray stepped down into the deck hatch, put his arms up high, and slid, the narrow boarding tube dropping him three meters into darkness. He dropped into the soft and narrow embrace of his fighter, feeling the acceleration couch mold itself around his legs and torso. His palm came down on a touch panel, and the cockpit lit up. Data flowed through his awareness, letting him know that the ship was powered up, checked green, and ready for launch. The fleet’s objective came up within a mental window.

  “What the hell is that?” Lieutenant Canby asked.

  “A baby planet,” Collins suggested.

  “A big rock,” was Lieutenant Ben Donovan’s guess.

  “Cut the chatter, people,” Commander Allyn said. “And listen up. The squadron is on indefinite hold.”

  Several of the pilots groaned in chorus. Indefinite hold meant they wouldn’t be launching immediately, that they would be stuck inside the bowels of America until someone up in CIC decided to set them free. The wait wasn’t entirely uncomfortable. Starhawk cockpits, after all, were designed to accommodate pilots for missions lasting for many hours, even days. Gray’s jackies and the seat beneath him took care of his biological output needs, and a small food assembler provided him with meals and fresh water when he needed them. But it was boring, waiting for hours, possibly, before PriFly decided to dump him into the Void.

  Gray and the other pilots of VFA–44 would be launching from the drop bays this time, rather than being fired out of America’s twin spinal rails. Located aft of the rotating hab modules, they connected directly with the hangar decks above them. When it came time to launch, Gray’s Starhawk would pivot ninety degrees, pointing out-and-down relative to the bay, the magnetic clamps would release, and the hab module’s rotation would drop him into space with a half G of acceleration—about five meters per second.

  A speed of 5 mps was insignificant compared with the 167 mps velocity of fighters fired from America’s 200-meter spinal launch rails, and the vector was out from the carrier, rather than straightforward, toward a distant objective. Both velocities, however, were insignificant compared with near-light, a speed the fighters could approach after just ten minutes of acceleration at fifty thousand gravities. The magnetic launch tubes were holdovers from an earlier day, when space fighters had been limited to eight to ten Gs because their acceleration was felt by their pilots. Periodically, critics of the Navy’s star carrier program wondered—often vociferously—why carriers had the launch tubes at all . . . or why they weren’t converted into kinetic-kill cannon like those carried by the Kinkaid and other railgun cruisers.

  Of course, so far as the hotshots in the squadron were concerned, there was simply no contest. Where was the coolness factor . . . getting dumped from a rotating hab like garbage, or being fired off the carrier’s bow at seven Gs? A fighter pilot had his or her image to consider, after all.

  Gray tried to approach the issue as a professional. It didn’t matter how you launched, so long as you had the delta-V to engage the enemy.

  He wondered what was waiting for them out there.

  Combat space patrol, though, meant they would be sticking close to the carrier battlegroup, deploying in a cloud just beyond the Confederation fleet’s perimeter. The idea was to keep the enemy far enough off that the capital ships could get through.

  “Hey, Prim!” Collins called, breaking his thoughts. “You’d better be in the fight this time!”

  “Lay off the kid, Coll,” Lieutenant Tomlinson said. “He was right where we needed him last time.”

  “Keep it down, people,” Allyn repeated. “Zen out and wait for it.”

  Gray waited.

  Shadow Probe 1

  Drop Bay 1, TC/USNA CVS America

  Outer Reaches, Alphekka System

  1232 hours, TFT

  “Shadow Probe One ready for launch.” Lieutenant Christopher Schiere added an electronic acknowledgement over his palm pad.

  “Copy that. You are clear for launch, One.” That was the voice of Commander Avery, America’s primary flight controller, better known by the term “space boss.” “Good luck, good hunting!”

  “Thanks, Boss.”

  “And launch in three . . . two . . . one . . . drop!”

  The CP–240 Shadowstar pivoted and dropped, plunging into space beyond the deeply shadowed bulk of the America. Within seconds, it emerged from the shadow of America’s forward shield, already turning to orient itself on the enigmatic object designated Al–01.

  “America CIC, this is Shadow Probe One, handing off from PriFly and ready for acceleration. Morphing to sperm mode.”

  “Copy that,” a different voice said in his head. “Shadow One, CIC, you are cleared for boost at your discretion.”

  “Thank you. I’ll see you guys on the other side.”

  The CP–240 was a slightly larger version of the SG–92 Starhawk, massing twenty-nine tons instead of twenty-two, and including provisions for a second pilot-passenger in its highly adaptive cockpit. Its AI was a Gödel 2500 artificial intelligence, a self-aware system far more powerful and flexible than the 900 models incorporated aboard Starhawk fighters. The spacecraft mounted no weapons, however, and its shields were considerably weaker. What made the CP–240 special was its effective invisibility.

  Experimental invisibility had been around since the early twenty-first century, but the science had matured from those first, single-wavelength laboratory demonstrations. Radiation passing through the Shadowstar’s shields fell onto an outer sheath of programmed nanoconduits that directed it around the recon craft’s hull and re-emitted it at a precisely calculated angle on the far side, making it seem as though light or radar signals had passed through the shielded space, rather than around.

  The technology wasn’t perfect. It worked best in open space, where most of the surroundings were black emptiness; if the ship passed between an observer and a complex background object such as a planetary disk or another vessel, there was distortion and a wavering halo effect around the Shadowstar’s edges. The invisibility wasn’t as good at higher wavelengths, either. Short ultraviolet tended to scatter rather than redirect. Perhaps most limiting, though, was the need to bleed off excess energy at high velocities. Like its SG–92 sister, when the Shadowstar was accelerating, it had to shed hard radiation from its quantum power tap
along the slender aft spike that gave the high-velocity incarnation the name “sperm mode.” If it didn’t, the ship would incinerate, but the high-e photon tail when it was boosting was a dead giveaway. So was the gravitational warping of nearby space as the ship fell toward its own projected singularity.

  But within certain parameters, the CP–240 was very good at what it was designed for, which was stealthy long-range reconnaissance.

  “The objective is at a range of ten point seven AUs, Lieutenant,” his ship informed him. “That is one hundred sixty-seven minutes at fifty thousand gravities.”

  Like all self-aware AIs, the artificial intelligence had a name—in this case Roger, after the twentieth-century mathematical physicist Roger Penrose. That choice of name amused Schiere, whose hobbies included the philosophies of physics. Penrose was still somewhat notorious for his strongly stated beliefs that computers could never become conscious or self-aware.

  That had been true, certainly, in the earliest years of AI research, when computers were algorithmically deterministic, and when, as Penrose had insisted, the known laws of physics could not explain human consciousness. All of that changed with the advent of quantum computers, of course, with software that was far more powerful than human intelligence, at least within certain narrow boundaries.

  “Allowing for a one-hour drift,” Schiere replied.

  “That has been included in the calculations, Lieutenant. Do you wish to see the precise mathematical evaluation?”

  “No, Roger,” Schiere replied with a laugh. “I trust you. Initiate boost.”

  “Accelerating at fifty thousand gravities.”

  The Shadowstar’s drives switched on, projecting an artificial singularity ahead of the ship for a tiny instant, switching off . . . then on . . . then off . . . creating a gravitational strobe forever flickering just ahead of the CP–240’s bluntly rounded nose. In that first second, the Shadowstar traveled five hundred kilometers. The vast, dark bulk of the star carrier alongside vanished, whipped away into the distance astern.

  And within moments, the universe itself began to reshape into the warped strangeness of relativistic flight.

  CIC, TC/USNA CVS America

  Outer Reaches, Alphekka System

  1516 hours, TFT

  Almost four hours into the boost, and America was now 1.2 million kilometers from Al–01, traveling at 73,200 kilometers per second . . . about 24 percent of the speed of light. The view ahead, as displayed by America’s AI across the low, domed overhead of the CIC, was just beginning to show the visual distortions invoked by the carrier’s high velocity, the stars beginning to bunch together toward the ship’s direction of travel.

  The three remaining ships of the inbound battlegroup, Crucis, Diablo, and Remington, had dropped in and formed up, though the bulky Remington was still lagging slightly behind the main body of the fleet.

  And by now, Lieutenant Schiere and his AI ought to be nearing the objective, whatever the hell it was.

  “America,” he said in his head, connecting with the carrier’s AI. “Update on the enemy fighter packs.”

  “All enemy fighters have begun accelerating, and are vectoring toward the fleet. They appear to have been caught somewhat by surprise, however, as most of them had outbound vectors. It will take many hours for most of them to intersect with our flight path. One fighter swarm, however, the nearest and designated ‘Fox-Sierra One,’ is decelerating now to match velocities with us. Fox-Sierra One will intersect the fleet in another thirty-one minutes.”

  “Understood. Thank you.”

  The enemy fighters, a swarm of at least sixty of them, were visible in the tactical display now, a cluster of red arrowheads astern and to one side of the fleet, playing catch-up.

  “The fighters near the objective don’t seem to be boosting at all,” Commander Sinclair pointed out. The CIC weapons officer had been linked in with the AI conference. “They’re sitting tight.”

  “That’s to be expected,” Koenig replied. “If they accelerate toward us, they would have to pass us, decelerate behind us, then accelerate again to catch up. They could do that, of course, and they probably will . . . but they’ll wait until we’re closer.”

  Matching velocities with another ship to the point that you could engage it in combat was always a tricky proposition. Fighters had enough of a delta-V advantage over capital ships that they could manage it, but it took time and finesse, and the target fleet could make things tough by jinking, changing acceleration, and throwing up clouds of anti-fighter munitions—sand clouds and high-G KK projectiles. The fighter swarm designated Fox-Sierra One had been the only fighters more or less astern of the main body of the carrier battlegroup, the only ones that could match vectors with relative ease.

  And that, in fact, had been a part of Koenig’s strategy. Had he given the order to turn tail and run, nearly every fighter in the system would have been astern and burning hard to catch up. Moving at close to c, they would have caught up long before America could slip into the metaspace safety of Alcubierre Drive. Plunging directly into the heart of the system—toward Al–01—gave the fleet a chance . . . at least until they’d passed the objective and began heading away from the objective, through the debris plane of the protoplanetary disk and into the depths of space beyond.

  “Let me see a long-range on the tac display,” Koenig said, looking into the tank. The image flickered and jumped. The twin stars glowed as tiny, side-by-side spheres at the center, surrounded by the broad red ring of the protoplanetary disk.

  He still couldn’t see the outer edge of the disk, however. “Take it back another notch,” Koenig said.

  The view jumped again. This time, the double star showed as a single point. The outer edge of the ring shaded off into ragged nothingness. Koenig pointed at a red icon out beyond the edge of the disk, and a third of the way around from Al–01’s position. “I thought I saw another fleet element out on the periphery,” he said. “What is that?”

  “We have designated that ‘Fleet Red Two,’ ” America’s AI replied. “It is the primary body of enemy capital ships in this system.”

  “What’s the range?”

  “Currently one hundred forty-two point five AUs.”

  A long way . . . nineteen light hours.

  “Still no grav signatures?”

  “No, Admiral.”

  Which was reasonable, since, at nineteen light hours’ distance, the light from the battlegroup’s emergence hadn’t reached them yet. What was puzzling, however, was the fact that—at least as of nineteen hours ago, since what America was picking up from CS–1 was nineteen hours out of date—the enemy fleet, composed of an estimated 315 capital ships and perhaps twice that many fighters, was so far completely inert. America’s long-range sensors had only just been able to pick them up as dim reflectors of starlight, and then only because a flashing radio beacon had announced their presence.

  It seemed strange to post so many warships together out beyond Alphekka’s debris disk, power them down, and simply let them drift in slow orbit. Koenig was beginning to think that they might be a mothballed fleet, ships unscrewed and unpowered. That would support the idea of Alphekka being some sort of a Turusch fleet depot, however. And so long as those ships hadn’t switched on their quantum power plants and started accelerating, they wouldn’t be a threat to America’s battlegroup.

  Which was good. There were 71 capital ships in the general area of Al–01, spread through a volume of space nearly 4 AUs across, plus 112 fighters. The odds against the Confederation fleet were quite long even without those silently drifting vessels.

  Perhaps they would know more when Schiere completed his recon flyby.

  Shadow Probe 1

  Inner Protoplanetary Disk, Alphekka System

  1517 hours, TFT

  “That thing,” Lieutenant Schiere said, “gives me the fricking willies.”

&
nbsp; “Which?” Roger replied. “Al–01? Or what’s behind it?”

  “Both, I guess,” Schiere replied. “But I was talking about the disk.”

  The protoplanetary disk showed on the Shadowstar’s screens and within Schiere’s own in-head display as a seemingly infinite plane composed of a kind of red graininess, like a low-res image of a red surface. His AI was continuing to superimpose infrared data on the optical image; even this close, at visible wavelengths the protoplanetary disk was a rather thin haze of dust and gas, and the larger chunks of rock were invisibly distant. The recon Shadowstar was coming in toward the plane of the disk at a fairly flat angle. Schiere’s velocity was now twelve kilometers per second, down from the near-c zorch of the majority of his 10.7 AU passage. He was, his instruments told him, already passing through the outer fringes of the disk.

  The protoplanetary disk was relatively thin even this far out from its star: 50 AUs from the two Alphekkan suns, it was less than seventy thousand kilometers thick. The objective, Al–01, was just skimming the outer fringe above the face of the disk, which had no clear-cut or definite boundaries. The Shadowstar’s sensors were actually detecting a wake behind the alien artifact as it plowed ahead through the thin haze of dust and gas. Nearby asteroids and comets—at 50 AUs from the double star, of course, none of the comets possessed tails—appeared as faint but gleaming stars compressed into a flat arc extending into the distance and curving around the suns.

  Schiere checked his instrumentation again. When he’d cut his drive an hour ago, he’d been more than 70,000 kilometers away from Al–01. Since then, he’d drifted 43,200 kilometers toward the object, while the object, orbiting the suns at 7.5 kilometers per second, had traveled 27,000 kilometers toward him. Their combined velocities had closed the remaining distance rapidly. It also meant that he would be flashing past the object at 20 kps, and most of the mission objectives would be carried out through Roger’s superhuman senses.

  Another three hundred kilometers. The objective was visible now as a tiny gray-white point of light ahead.