ONLY THE SHIELD Shad saved the Enterprise from destruction.
If Captain Kirk had not put his ship on red alert, thus automatically bringing the shields into play, the titanic explosion would have sent more twisted junk—the former Enterprise—to join the tumbling debris already in rapidly decaying orbit around Centaurus.
But the starship's shields, while good, were not invulnerable. A small fraction of the raw power of the blast had leaked through to them, to crash against the tough outer skin of the Enterprise. That remaining force was more than enough to override the ship's inertial dampeners and cause further problems.
On the bridge, Kirk painfully got to his feet and looked around. Everyone had been thrown to the deck. "Sulu!" he called. "How's our orbit?"
The helmsman had already struggled back into his seat. He consulted his board. "Steady in standard orbit, Captain. Whatever that was, it didn't slow us down."
"Good. Maintain the shields; full emergency power. Chekov, keep a sharp eye out for incoming fire." Kirk glanced here and there around the bridge, looking for problems. There were a couple of minor circuitry fires and a lot of acrid smoke; the circuits in several boards had overloaded. But even as Kirk watched, the automatics cut in and a fog of anticombustible, heavier-than-air gases writhed along the surfaces of the affected stations. The fires died aborning, but there was no telling how much damage might have been done.
"Captain," Spock called. "Our sensors show we were hit by a nuclear explosion with an estimated yield of three million metric tons of trinitrotoluene—"
"TNT" to you and me, thought Kirk.
"—and I am attempting to coax a damage report from the computers," Spock continued. "The blast occurred approximately fifty meters off the port nacelle. I can report that our shields are forty-three percent depleted from deflecting the explosion; we do not have the energy reserves to survive more than one additional blast of similar size." The science officer paused. "It also appears we have lost most of the emergency repairs made by Mr. Scott and Chief MacPherson."
As if on cue, the lights on the bridge began to flicker, which brought a frustrated snort from MacPherson, again standing tall at his engineering station. The big Scot began to hit buttons and slide switches up and down; the lights began to glow more steadily.
"Try your best to keep the air and gravity going, Chief," Kirk said. "Anything else can wait."
"Aye, sir," responded the Scot. "Anythin' else is gonna have t'wait, if ye don't mind me sayin' so. All th' backups appear shot—burned out from overload—and we've been usin' most everythin' else t' carry power around the ship. I'll do me best, though, Cap'n."
Kirk looked at the main viewscreen. Things looked quiet. Stars occupied the upper half of the screen, and below them an arc of the planet shone brightly bluish. There was nothing else. "Anything approaching us, Mr. Chekov?"
"Negative, Captain," the navigator replied. "I am on maximum scan; sensors are nominal. Nothing out there, sir."
Kirk nodded and, limping slightly, walked to his command chair and resumed his seat. He swiveled it to face Uhura. "Lieutenant," he said, "do we still have a line through to Sickbay, or is that gone, too?"
Uhura shook her head. "No line, Captain. No communications lines left from anywhere to anywhere. I've already had ship's stores begin to distribute communicators to all department heads and anyone else with a need for one, but it'll take a while; Security has to deliver them by hand, since all the tubes are out. I have about half a dozen up here already, though." Uhura ducked and slid open a panel at her feet; she took out several communicators and tossed one to Kirk, who needed both hands to catch it.
"Thank you, Uhura," Kirk said as the communications officer called out, "Mr. Spock? Your communicator, sir." She pitched it underhanded in the science officer's direction. Without looking, Spock snatched it out of the air and, with his eyes still glued to the data read-out in his viewer, placed the communicator on his belt. "Thank you, Lieutenant. I will have need of it."
As Uhura distributed the remaining communicators to Sulu, Chekov, MacPherson, and the Security officer on duty, Kirk flipped his open. It tweeted and Kirk said, "Bridge to Sickbay. Bones, are you there?"
A tired but familiar voice answered. "I'm here, Jim. I've been carrying this communicator ever since Scotty told me not to worry about the intercom lines getting fixed. What is it?"
"I need a casualty report, if you can give me one. How's it look so far?"
"We were lucky," McCoy said flatly. "My environmental readouts—if I can trust 'em at this point—show the outer skin of the ship was hit by a level-nine burst of primary and secondary nuclear radiation. That blast couldn't have been far off—"
"It wasn't."
"—but radiation levels inside the ship are so damn near normal, I'm tempted to say forget about it. Levelnine exterior exposure is within safety limits, anyway. M'Benga and a couple of nurses are making a quick trip through the ship to see what's going on, since we can't call around. I'm getting reports from them of injuries from blast concussion—people falling down and being thrown into things—but nothing serious, nothing we can't handle down here, and nothing you should worry about. I'll get you a sick list as soon as I can. Anything I should know about on the bridge?"
"No, nothing major," Kirk said, then paused. "Uh, I think I twisted my knee."
"The right one?"
"Yeah. But it's feeling better now."
"I'll look at it later. I worked too damn long on that knee to have you go and wreck it. Try to stay off it, and I'll see you later. McCoy out."
Kirk flipped his communicator closed as Uhura called out, "Captain, I'm still getting that lightspeed radio signal from the Ministry of Emergency Communications in McIverton. They sound frantic, sir."
"Put 'em on," Kirk ordered, and Uhura did. "This is Kirk, commanding Enterprise. Go ahead, McIverton."
"Kirk! This is Erikkson. Thank God you're all right! We saw the explosion and thought you'd had it—"
"We almost did. Just what the—what is going on, Mr. President?" Kirk demanded. He thought the president sounded frantic.
"Captain, our planetary defense system is out of control and has been ever since we lost New Athens. Every effort we've made to shut it down has failed. The system attacks any ship approaching the planet, and we can do nothing to stop it from doing so. We tried to warn you off, but there wasn't time."
"Yes, you did try," Kirk admitted. "We didn't pick up your signal until it was too late. Go on, please."
"Subspace communications are out because of tachyonic interference," the Centaurian president said. "I'm speaking to you over this old lightspeed radio transceiver the Ministry of Communications dug out of the Colonial Museum. It doesn't have much range, but it's the only thing we've got that can penetrate the interference blanket."
"What about the defense system?" Kirk asked. "What's wrong? Why is it attacking Federation craft?"
"Our defense system is similar to that used by most Federation planets," Erikkson explained. "We use ground-based multimegaton-range nuclear weapons to deter approach by enemy forces. The Defense Center complex is near New Athens. Our General Staff says the antimatter blast must have deranged the computers controlling the system so that anything approaching the planet is assumed to be an enemy."
"Have you tried disarming the system?" Kirk asked.
"Nothing's worked, Captain!" Erikkson replied, with some heat. "The stand-down code has been sent thousands of times, with no effect. We've sent repair crews to the Defense Center site; they've made no progress in reprogramming the system or shutting it down!"
"Please, Mr. President, go easy," Kirk said. "I need to know; I'm not challenging your judgment." This man's one millimeter away from a breakdown of some kind, Kirk thought. I don't think I've ever heard a voice riding so close to the edge.
Erikkson paused, and then continued in a calmer tone. "Look, Captain, right after New Athens went up, everything in orbit—freighters, passenger liners, flitters, satellites, whatever—was targeted and destroyed. We lost scores of ships. Things were chaotic; most of the government was killed in New Athens, including the old president and vice president. I was minister of state in the old president's Cabinet. I and two other members of the Cabinet were making an inspection tour of our west coast government offices when word came of the explosion at the spaceport. I've been trying to run things from here ever since; I've had to deputize half a replacement Cabinet from clerks and career bureaucrats, just to keep things moving along.
"After it became clear that the defense system was attacking anything and everything in our sky," Erikkson continued, "I put the code seven-ten into effect. Then the three medical ships from Earth came. We saw them and tried to warn them—but they apparently weren't monitoring lightspeed radio frequencies. They never heard us, Kirk. They were blasted—and we couldn't stop it. We had to watch those ships die."
"Well, there's one thing we may be able to do right away," Kirk said. "Lieutenant Uhura, how much interference are we getting on subspace channels?"
"The tachyonic blanket is still smothering all space-to-ground channels, sir," the communications officer replied. "We're so close to Centaurus now that there's heavy interference on all other subspace frequencies, too—but I think I can punch a signal through to Starbase Seven."
"All right, do it," Kirk said. "My compliments to the commander of Starbase Seven, et cetera, and make our report. Uh, tell him I've put Centaurus under quarantine, with the approval of its government; have him inform all ships to stay away until further notice. The Enterprise is beginning relief operations. Append a report on our status. Sign it and have Seven relay it to Starfleet Command."
"Thank you, Captain," Erikkson said wearily. "It's a great load off my mind, a great load. Tell me—do you have any ideas about how to disarm our defense system? The minister of defense is here with me, as is the minister of internal security. We are all very anxious to help. Please, Captain, do you have any ideas?" The president's voice had taken on a pleading whine.
Kirk swiveled his chair to face the science officer's station and looked inquiringly at Spock. The Vulcan nodded, and Kirk said, "Gentlemen, this is my first officer, Commander Spock. Mr. Spock also serves as science officer. I believe he has something helpful to say. Go ahead, Spock."
"Yes, by all means, by all means," Erikkson replied quickly. "Mr. Spock, first let me introduce the men with me the minister of defense, Daniel Perez, and the minister of internal security, Nathaniel Burke." There were brief grunts from the two men.
"Greetings, gentlemen," Spock said politely. "Minister Perez, have you considered the possibility of a direct attack on the site of the Defense Center?"
"Certainly we have," Perez answered, "and we dismissed it out of hand. Commander, the central processing complex of the Defense Center computers is contained in a shielded vault four hundred meters below the surface. Nuclear weapons won't touch that vault; we built it to last. The only way I know to breach the vault is to hit the Defense Center site with annihilation weapons in series, and I think you'll understand we don't wish to do that."
"Of course," Spock said. "Quite understandable, Mr. Minister. May I ask what happened when, as the president said, you sent the stand-down code?"
Perez sighed. "No reaction at all. The computers ignored the code. We expect that any approaching enemy will attempt to generate a great number of random codes in order to confuse the system. Our stand-down codes are, thus, randomly generated and subject to many different kinds of verification before they are implemented. My experts tell me that, somewhere along the way, the computers have lost a step in that verification process and so will refuse to recognize any code as a stand-down code."
"So the computers will not stand down because no stand-down code is possible," Spock said. "The system will attack, and keep on attacking."
Suddenly Spock paused thoughtfully, his right eyebrow arching; he swiveled his seat to face Kirk. "Captain," he said, "I must point out that, while we have been attacked once, there have been no follow-up strikes. I deduce that either the Defense Center computers erroneously consider us destroyed, or they are no longer capable of pursuing an initial attack. Either way, this indicates severe damage to the computers' logic centers. It also suggests a weak point from which the problem might be addressed. If our own computer complex were intact, I might be able to begin my investigation from here. Under current circumstances, however, I must go to the site of the Defense Center to see what, if anything, can be done."
Kirk considered it, and finally nodded. "Mr. President, will you and your Cabinet ministers please stand by? I think we might have an approach."
"Of course, Captain," Erikkson answered. "Standing by."
Kirk whipped out his communicator and flipped it open. "Kirk to Engineering. Come in, Scotty." There was a brief wait, and then the burr of the chief engineer's voice came tinnily from the communicator's small speaker. "Aye, Cap'n. Scott here."
"Scotty, do we have enough oomph left to beam Mr. Spock and a team of, er, two technologists down to the surface?"
"Cap'n, after our original problems, I'd routed every transporter circuit through any spare pathway I could find, but thot was all undone by th' nuclear blast. Th' pathways have been randomized, and I canna reconstruct 'em. Th' compensators are out, too; I could perhaps disassemble a landing party, but I nae could put it back together."
Spock spoke up. "I'm quite willing to take the risk alone, Captain."
The chief engineer broke in. "Pardon me, Mr. Spock, but it's nae risk; it's guaranteed disaster. Take a look at yer readouts and figure it out; ye know th' equations as well as I do." To this, Spock nodded slowly. He'd already seen the transporter data readouts; the mathematics were unassailable.
"Captain?" Spock said. "I might suggest going down to the surface in a shuttlecraft."
Kirk gestured an emphatic negative. "No. Even if this ship is now safe from attack—and that's not guaranteed—the defense system is still tracking and attacking anything that approaches the atmosphere. From what Erikkson said, that includes shuttle-sized targets."
Spock nodded. "However, Captain, there are three possibilities here. One is that we have been marked 'destroyed,' and are being ignored. Similarly, a shuttle departing from this ship will be ignored, perhaps as detached debris. The defense system will not respond to anything we do. To it, we do not exist."
The Vulcan paused. "The second possibility is more risky. The defense system will see the shuttle depart from this ship, judge the situation as a new enemy attack, and fire on the shuttle. I must point out, though, that we were hit upon our arrival only because the system detected our approach and had enough time to launch a missile on an intercept course for us; a shuttle departure will take it by surprise. It will have to intercept the shuttlecraft in the atmosphere; the Enterprise herself would be safe. And the shuttle can fly a zig-zag pattern to avoid the intercepting missile."
"And the third possibility?" Kirk asked.
"That the defense system will see the shuttle leave, decide that the Enterprise is not destroyed, and launch a new attack on her as well as on the shuttle."
Kirk shook his head. "And what are the odds against avoiding another attack on this ship, Spock?"
The science officer looked as unconcerned as ever. "Unknown, Captain; I have no data. But it is necessary for me to go to the Defense Center site, and going there in a shuttle offers some hope of success."
Kirk was about to disapprove Spock's plan because of the risk to the Enterprise when he caught himself and paused.
"All right, Spock," he said at last. "You can go. But I'm going, too."