Kessler straightened in his seat. “That is my project. And its real name is Lightfall. ‘The Killswitch’ is Collins’s nickname for the device, and everyone on the team started calling it that.” He was obviously unhappy about sharing this information.
“I’ll bet it’s not a new kind of blender,” Grant said.
“You are an idiot,” Morgan said. “This is a DARPA black project. Lightfall is a weapons program.”
“What does it do?” Tyler asked.
“I don’t have time for this,” Kessler said, jumping out of his seat. Tyler could imagine how shaken the scientist must be, knowing his life’s work had been stolen.
“Dr. Kessler,” Morgan said, “this is more important than anything else you could be doing right now. Please sit down.”
Kessler looked at the door and grumbled, but he took his seat, massaging his temples as if he were soothing a headache. After a few moments, he said with a tired voice, “You, of course, know what an EMP is.”
Tyler nodded. “When an H-bomb explodes at high altitude, it blasts out an electromagnetic pulse that fries anything with a computer chip.”
“So the Killswitch is a nuke?” Grant said.
“No, it is much more sophisticated than that,” Kessler said. “Under Project Lightfall, we designed the bomb to emit the pulse without a thermonuclear explosion. The weapon has the capability to penetrate hardened bunkers and vehicles, even at low altitudes, and it leaves no residual radioactive fallout.”
“So it could be used in conventional wars,” Tyler said.
“It’s not my place to say where or how it’s used. That’s for military commanders and politicians to decide.”
Grant grunted.
“I suppose you have a problem with me being a weapons developer,” Kessler said.
“Not at all. When I was in the Rangers, I wouldn’t have minded setting one of those babies off over a tank division that I was about to engage. Would have made my job easier.”
That seemed to calm Kessler. “We were planning to do our first test next week at the Woomera range south of here.”
“Why Australia?”
“The Australians have material critical to operation of the weapon. It was a joint development.”
“What material?”
“You don’t need to know that.”
Tyler was confused. “If the weapon was stolen, then why the truck bomb?”
“A cover-up attempt,” Morgan said. “If that truck had made it through the gates and blown up Pine Gap, everyone here would have been killed. The ensuing investigation would have come to the conclusion that the weapon was destroyed in the explosion.”
“How powerful is the bomb?”
Kessler rubbed his mouth. “It depends on the yield of the trigger. That’s what we were hoping to find out with the tests. But my estimate says that an airburst at an altitude of thirty-five thousand feet would disable everything within a thirty-mile radius.”
Grant leaned forward, slack-jawed at the weapon’s destructive potential. “That’s the size of Washington.”
“Or Paris. Or Beijing. If the Killswitch is used to take out a major city, the effects would be catastrophic.”
“Now you see why we need your help,” Vince said. “You can identify the thieves.”
“How did they steal it?”
“We’re still tracking that down. But it looks like it was done in transit, on the way here from the Alice Springs airport. The truck never showed up. With the police investigating the warehouse deaths and the explosion, we’re stretched thin looking for it.”
“What about the airport?” Tyler said. “Roadblocks?”
“The Alice Springs airport is tiny, so we’re checking every plane flying out. Roadblocks are more difficult. We can’t have the police stop every car and truck leaving the area to do a thorough search without telling them what they’re looking for.”
“You can’t exactly put out an all-points bulletin advertising that the US military lost something that could send Sydney or Melbourne back to the Stone Age,” Grant said.
Vince nodded. “The press would get hold of it in no time, and then we’d have a panic on our hands.”
“But it can’t be set off,” Kessler protested. “Not without the trigger.”
Morgan sat with a mixture of sigh and growl. “Dr. Kessler, it’s about time you tell us exactly how the Killswitch works. And I mean everything.”
Kessler stood and glared at Morgan. “I reiterate my protest. These men are not properly vetted—”
“Your protest is noted,” she said. “Continue.”
He seethed for a long minute before finally throwing up his hands in defeat. “All right,” he said, pacing as he spoke. “Do you know what hafnium is?”
Tyler didn’t hesitate. “It’s a metallic element. It doesn’t have many uses, but it’s important in the cladding of nuclear fuel rods to control the reaction.”
Grant tapped the table. “Wasn’t there something about a bomb that used a hafnium isomer? I read about it a few years ago. DARPA was developing it, but there was some controversy over whether it actually worked.”
“How do you know that?” Kessler said in amazement.
“Well, we
“After those articles came out, all future press communication on the process was halted,” Kessler said.
“Let me guess,” Tyler said. “Because it works.”
Kessler nodded. “It’s called induced gamma emission. And yes, it works. Hafnium-3, the isomer you mentioned, is the most powerful non-nuclear explosive in existence. One gram of it has the explosive power of three hundred kilograms of TNT.”
Grant whistled in appreciation. “Good things come in small packages.”
“The Killswitch uses an isomer trigger. Without it, the weapon is nothing more than a very expensive bomb. All other EMP weapons with an effective range of more than half a kilometer are either nuclear or the size of a house, making them impractical in battle situations. Using a hafnium isomer to generate the gamma radiation necessary, we were able to shrink the weapon to only fifty kilograms, and half of that weight is for the plastic explosive to set off the isomeric reaction in the trigger. Most of the design expense went into compacting the weapon into such a small size.”
“So the Killswitch is triggered by hafnium-3?” Tyler asked.
“No. Production of hafnium-3 is prohibitively expensive. It would cost a billion dollars for just a few grams. We have something even more powerful. A hafnium isomer called xenobium. It’s more stable than hafnium-3 and twice as powerful.”
Tyler chewed his lip. “You glossed over the fact that both hafnium-3 and induced gamma emission weapons emit gamma rays. How deadly is this xenobium?”
“It can be carried safely in a shielded lead container.”
“And the gamma rays from the explosion of the Killswitch?” Morgan said.
Kessler looked around the table and cleared his throat. “At low altitudes the explosion would produce a lethal dose of radiation for anyone within a mile or more depending on the size of the xenobium trigger.”
“Sounds like a nuclear weapon to me,” Grant chuffed.
“It is non-nuclear in the sense that it is not a fission or fusion device, and as I mentioned there is no lingering radioactive fallout. Beyond the immediate region around the explosion, the effects are not fatal.”
“Supposedly. Didn’t you just say that you haven’t tested it yet?”
“Of course. All our calculations are purely theoretical at this point.”
Everyone went silent at the potential catastrophe if the weapon was set off in a populated area, possibly on July twenty-fifth.
