Motion.
Sean caught it first as the LAM swept the far end of the room, beyond where Lewis had fired. That target had blocked the sergeant’s view of the scene beyond, and Goldfarb was not yet in position to see what his commander was seeing.
Asunción had ducked as a reflex when the crack of an explosion invaded the command bunker. But duty quickly overcame his natural reactions, and he began to rise, the launch button right there, just inches from the finger that he was stabbing toward it.
Man. His back was to Sean. Hands moving. The laser dot danced across the target’s back to a point between the blades before Sean squeezed the trigger. A three-round burst of 9mm rounds spit from the front of the MP5SD4 with hardly a flash. There was a sound to accompany the meeting of lead with flesh, but it was not from the weapon. Not from Sean’s, that is.
General Juan Asunción’s final act was hardly a difficult one, but it set in motion a complex series of actions that were to culminate in a disastrous event, though not that which he had envisioned when his finger came down upon the launch button.
The first manifestation was probably the least involved. A minute electrical current traveled five hundred yards through a wire, buried with many others in a conduit running from the command bunker to Tower One. A backup radio signal would have been transmitted if there had been a problem with the power, but there was not. The pulse of energy reached a sequencer box just behind the missile’s guidance package. Here it “tripped,” in sequence, a series of electrical switches. The first initiated a wholly separate signal that ordered the explosive bolts securing the missile to its launch pedestal to fire. All twenty did, breaking the bonds that held the weapon in place. The second switch started four separate pumps near the base of the booster’s first stage. Two of these were primary and two secondary, and all four began drawing the two liquids from their separate tanks in the first stage but were stopped from delivering the propellant combination to the combustion chamber. The final switch in the sequencer removed the intended blockage, activating a series of piston-driven drop valves that allowed the hypergolic mixture of undimensional dimethylhydrazine and nitrogen tetroxide to flow under tremendous pressure into the bulbous first-stage combustion chamber.
It was there that the mating of the two products, which should have reacted with a predictable violence, began to do something very unexpected, though quite preventable.
The combination of UDMH and NTO, a standard fuel/oxidant mixture used in Russian and Chinese liquid-fueled rockets for decades, was ideal for the purpose because it required no ignition source. The two liquids reacted on contact with each other, in essence exploding in the confines of the combustion chamber, which contained and directed the energy of the reaction through the gimbled thrust nozzle at the missile’s base. As expected, the reaction occurred, spewing a massive jet of flame downward as the powerful engine began to push the Chinese-built missile upward toward the opening of Tower One. Everything was working perfectly. The guidance system was already reading the thrust level and minute attitude shifts, and began factoring the “actual” with the “planned” to correct any deviations that could alter its six-thousand-mile flight course to Moscow. Pumps were whirring robotically without care for the limited life they would have. All was as Anatoly Vishkov had seen to. All, that is, but one thing that he could not control, but that he had warned of. The sharply pointed nose cone was within a yard of clearing the confines of the tower when the unseen error of the fueling crew manifested itself completely within a fraction of a second.
UDMH and NTO, like all combinations of fuel and oxidant, require a precise mixture quotient to react at a level that is proper for their use in a set space — the combustion chamber, in this case. The concentration and amount are critical, and here they had been altered by the use of the contaminated NTO as a primer during fueling from the tank trucks. The nitrate infiltration that Vishkov had feared did happen when the rainwater filtered through the nitrogen-rich soil into the supercooled NTO. The water, in contact with the frigid gas in liquid form, instantly froze, creating a layer of highly crystalline ice atop the oxidizing agent. What nitrates had been held in solution with the rainwater then settled from the ice sheet and contaminated the NTO solution with salts of nitric acid, which again dissolved and upset the delicate balance needed for a successful and controllable hypergolic reaction. In effect the NTO had been diluted by the addition of stable nitrates to the solution, which meant that a higher than normal ratio of UDMH to pure NTO was reacting in the combustion chamber. What occurred when that ratio drifted past the 3 percent variance in favor of the UDMH was similar, though quite a bit smaller, than the effect the opposite end of the missile was designed to unleash.
In less than the blink of an eye the loss of equilibrium in the reaction caused the energy level to rise dramatically and instantaneously. The additional UDMH overtook the reaction, increasing the controlled explosion to a point where the design limit of the combustion chamber was surpassed. The chamber literally fractured into hundreds of sections as the force of the explosion pushed outward in all directions. Traveling upward, it destroyed the pumps, feed lines, and finally the lower tank of NTO. The upper tank of UDMH ruptured a fraction of a second later. Before the liquids could join, they were acted upon by the fireball rising upward and were themselves added to the mix, feeding the uncontrollable inferno. At that point the effect became that of a very large bomb, whose force searched for avenues of escape from the already failing cooling tower that contained it. One route was through the exhaust vents at the base, but the larger opening at the top saw most of the energy pass through it, rising from bottom to top, generating a force that propelled all things in its path skyward.
One of these was the warhead.
Lieutenant Duc had the Pave Hawk in a tight left turn when the night became day for a few seconds.
Joe strained against his belt to look out the open left side door as the helicopter reached a due-west heading. “No…”
The fireball was rolling into the sky, a mass of orange and black and yellow that curled outward and in upon itself. Joe followed the inferno to its source, looking for the structure from which it had come. But it was not there. Just a spreading sheet of flame and smoke lay where Tower One had been. And where those men were supposed to be.
Seven feet ahead, Lieutenant Duc was realizing the same loss when the net came alive.
“Raptor to Gambler, you have company. Sandman reports a bandit at your—”
The report abruptly ended as a burst of 30mm cannon fire ripped through the Pave Hawk from somewhere to port. It stitched across the cockpit, left to right, and continued back into the cabin, drawing a line of the inch-diameter rounds through the gun stations on both doors. Duc’s copilot received four hits, all traveling through his midsection before continuing out and through the helicopter’s windscreen, leaving gaping holes in front of the pilot. Other rounds impacted the metal structure between the cabin and cockpit, penetrating and ricocheting, one passing just an inch from Duc’s chin as it severed the line from his headset to the radio and intercom. Behind him both door gunners were dead, like his left seater, but Anderson had received only a superficial wound from a metal fragment blasted free by a 30mm round.