metres distant – to carry out final communication checks with the cruise missiles. And then everything was ready.
The commanding officer glanced round the bunker, nodded his approval, and then uttered the single word: ‘Launch.’
On the concrete pads, the liquid-fuelled engines ignited almost simultaneously and, with a roar that seemed to shake the bunker, the three missiles leapt into the air, their paths diverging immediately.
‘Zero Six, Chunghwa. All missiles have been fired. Detonation in approximately six minutes. Stand by to turn onto south.’
‘Zero Six.’
The North Korean plan was simple enough. The three HY-2s each carried a nuclear warhead, but the weapons weren’t aimed at any strategic targets to the south of the DMZ. Instead, each cruise missile had been programmed to fly across the Demilitarized Zone at low level, thus avoiding engagement, and perhaps even detection, by the Patriot batteries. Once well inside South Korea, the missiles would climb to high level where the warheads would detonate, hopefully simultaneously.
Their separation would ensure that the electromagnetic pulse the explosions generated would blanket the entire width of the Korean Peninsula along a line running east–west directly through Seoul. That, they hoped, would destroy every computer, radio, radar, communication system, and anything else that contained a memory chip or printed circuit, throughout the northern half of South Korea. Due to the fall-out, the explosions would probably also kill a large number of people, as might the blast itself, depending upon the altitude and yield of the devices, though nobody in Pyongyang cared about that.
But the North Koreans had a problem. In fact, they had two problems. The first was that cruise missiles are designed to fly horizontally at low level and fairly fast, which was ideal for avoiding the Patriot batteries, but the optimum detonation point for an EMP weapon is as high as possible. It’s been estimated that a high-yield device detonated over central North America at an altitude of about two hundred and fifty miles could affect every electrical circuit in the continental United States. Yet the maximum height Pyongyang had calculated the HY-2 could reach with its heavy warhead was only about twenty thousand feet.
The second difficulty was the yield. The power of the EMP is proportional to the prompt gamma-ray output, and in a fission explosion this equates to under four per cent of the total power of the device. This is substantially reduced by the high explosive used to initiate the detonation sequence, which can absorb as much as eighty-five per cent of the prompt gamma-rays. So for a ten-kiloton device – about the maximum power the scientists at Yongbyon had calculated their weapons would produce – the overall power of the EMP would be well below one per cent of the total yield. But that, they hoped, would still be enough.
The Foxbats were the insurance policy. They would hold north of the DMZ ready to take out any aircraft that the Americans or the South Koreans managed to launch. Then, with the American Patriot batteries blinded, their radars burnt out, and the CFC emasculated, the third stage of Pak Je-San’s plan would begin.
‘Missile launch! Right two o’clock range about twenty miles. Two… no, three weapons.’ Roger Whittard’s voice was loud and excited.
‘My RAW’s not picking anything up,’ the Senior Pilot said, ‘but I see them too.’
‘They’re not SAMs,’ Richter said. ‘They’re cruise missiles. This looks like the opening salvo of North Korea’s invasion plan. The Patriots won’t be able to stop them, but maybe we can. Vipers, you take the one tracking south-west, which looks like it’s heading towards Seoul – and we’ll handle the other pair. I’ll hit the easterly one, OK, Splot?’
‘Roger that.’
Richter hauled his Harrier round in a tight descending port turn and pointed the nose almost straight down. Although the HY-2, like most cruise missiles, is subsonic, he knew he had a very limited window of opportunity to engage it. The missile was probably faster than his aircraft, so he had to plan the intercept carefully, and bring his Harrier in right behind it so that the Sidewinder could lock on. Once he’d released the missile, the ‘winder would certainly catch it: the weapon has a maximum speed of Mach 2.5.
The altimeter was unwinding at an alarming rate, the ground rushing towards him, but Richter wasn’t looking at his instruments, or even the HUD. His whole attention was focused on the scene out of the right-hand side of his cockpit, where a tiny grey dart, trailing a plume of smoke, was heading south-east at close to the speed of sound and very low. It looked to Richter as if it was less than five hundred feet above the ground, which wasn’t going to help him any.
Intercepting it would be difficult, he knew. That was one worry. The other was the Patriot batteries that studded the southern side of the DMZ. His Harrier was wearing a squawk issued by air traffic control at Seoul, but he couldn’t remember if the PAC-3 radar incorporated SSR identification. If it didn’t, his aircraft might be interpreted as an incoming ballistic missile, and it would really piss him off if he himself got shot down by the American or South Korean forces.
‘British aircraft over South Korea, this is Hawkeye callsign Alpha Three on Guard, do you read?’
‘Alpha Three, Cobra Two, you’re loud and clear, but we’re a little busy right now.’
‘You’re likely to get a lot busier, buddy. There are twenty-one interceptors heading straight for you out of bandit country. We estimate they’ll be all over you in around ten minutes.’
‘Thanks… I think,’ Richter said. ‘Keep us posted, please, Alpha Three. We’re chasing three cruise missiles right now.’
He risked a quick glance at the HUD. His Harrier was passing ten thousand feet in a near-vertical dive. The Seersucker was in his two o’clock position at about three miles. It was time he stopped descent and turned to intercept. He was going to have to turn left, allowing the missile to fly underneath him, if he was to stand any chance of getting into a firing position. And the problem was that, as soon as he turned, he’d lose sight of the missile. It really was a one-shot option.
Richter checked the position and speed of the HY-2, then his altitude, trying to do the calculations in his head. Seven thousand feet. Six. Five and a half. He took one more glance at his target, another at the rocky terrain directly below him, then pushed the control column over to the left and eased it back slightly. The g-force pinned him into the seat as the Harrier turned hard to port, its rate of descent slowing rapidly.
He pulled the GR9 level at two thousand feet, heading south-east, and looked all around him. There was no sign of the cruise missile, but it had to be somewhere close by. He daren’t turn, because that would bleed off so much speed he’d never then catch it, and he couldn’t slow down for exactly the same reason. He just had to hope that his turn had been accurate enough.
Then he saw it. Around a thousand feet below, passing on his left-hand side about a mile away – and travelling much faster than Richter expected. He turned his Harrier gently to port, aiming for an intercept course, made sure the throttle was fully open, and pushed the control column slightly forward.
He selected the Sidewinder on his port wing and immediately checked that the broken circle appeared in his HUD. The HY-2 was on his left, in the eleven o’clock position, on a more or less constant bearing, so he knew his heading was good.
Without radar, he had to estimate the target’s range by eye alone, but he reckoned that he was about half a mile behind it. And already he could hear the growl of the ‘winder as its infrared seeker began picking up the cruise missile’s exhaust plume.
Then the HY-2 pitched up and began climbing. Richter had expected the cruise missile to stay low until it hit its target. The climb suggested something different, and after a moment he guessed what the North Koreans might have planned.
‘Flash. All callsigns, Cobra Two. My missile’s climbing. It’s possible these could be air-burst nukes.’
‘Viper Two, this one’s doing the same.’
Richter pulled the control column back, starting the Harrier in a steep climb to follow the Seersucker.
In the nose-cone of the HY-2, the radar altimeter recorded an altitude of two thousand metres, and sent a signal to the simple computer – little more than a glorified timing device – that controlled the warhead. It immediately activated the pre-detonation circuit check. The device was designed to explode when it reached a
