The chief nodded. “Actually, it was only one missile,” she said. “But it was armed with three nuclear warheads.”
“CNN is claiming seven warheads,” Ann said.
“There were seven reentry vehicles,” Chief McPherson said. “Three of them were nuclear warheads. The other four were decoys, designed to tie up our resources, and force us to expend interceptor missiles.”
She pointed to a small symbol on the chart, a red downward-pointing arrow enclosed in a red circle. “The missile was launched from a nuclear submarine at this position, in the northeastern Sea of Okhotsk, about thirty-seven hours ago. The sub in question is hull number K-506, a Delta III class, built in the nineteen-seventies. It carries sixteen ballistic missiles, each of which is armed with three nuclear warheads and four decoys. It’s already fired one missile, so it’s still got fifteen missiles left in the launch tubes. That’s the submarine we’re talking about: the one that launched nukes at the West Coast.”
“And we can’t take a chance on spooking it,” the captain said. “If we use your acoustic communications system and the sub intercepts one of your signals, it’s going to kick up to flank speed and run like hell. It’ll hide so far up under the ice that we’ll never get close to it.”
“I agree, sir,” Chief McPherson said. “We may just have to settle for cueing. Send the Mouse unit under the ice to do the job in full auto mode, with no external comms. If it finds anything, it comes back out, drives to the surface, and calls us on low-power UHF.”
“That’s detectable too,” one of the officers pointed out.
“True,” the chief said. “But only at short range line-of-sight, and not by the sub. The UHF signal might get intercepted by an aircraft, but a submerged submarine will never pick it up. It’s not a perfect solution, but it’s probably the best we can do.”
“You’re probably right,” the captain said. “Can anyone suggest an alternative?”
No one spoke up.
“Alright,” he said. “We go with the UHF, and stay away from underwater comms. If Mouse gets a hit, it comes to the surface and calls us on low-power UHF.”
He looked at Chief McPherson. “Continue, please.”
The chief leaned over the chart and the red symbol with her fingertip. “This is ‘datum.’ It’s the last known position of the submarine.”
She waved a hand in a big loop over the chart. “The maximum submerged speed of a Delta III is about 25 knots. If the sub is running pedal-to-the-metal, it could be 900 nautical miles from datum by now. In other words, it could be anywhere in the Sea of Okhotsk.”
Sheldon craned his neck to get a better view of the chart. “Why are you assuming that the sub is going to stay in the Sea of …” He paused. “How do you pronounce it again?”
The chief smiled. “The Sea of Okhotsk. We call it the Sea of O, for short.”
“Thanks,” Sheldon said. “So why are you assuming that the submarine is going to keep to the Sea of O? If it can run 900 miles in 36 hours, it could be through those islands and out into the Pacific right now.”
“We don’t think he’s going to come out,” Captain Bowie said. “As long as that sub skipper stays in there, he’s got the tactical advantage.”
“How so?” Sheldon asked.
“The Sea of Okhotsk is covered by the Siberian ice pack,” said Chief McPherson. “Ships can only get into the very southern end of the sea, because of the ice. As long as it stays in there, the sub can hide under the ice, where it’s protected. If he comes out into the open ocean, we’re going to eat his lunch, and he knows it.”
Ann set her coffee cup on the table. “Where do we fit into this? I assume you dragged us out here for a reason.”
“That submarine still has forty-five nuclear weapons on board,” Captain Bowie said. “We’ve been assigned to engage it before it launches another nuclear attack. Unfortunately, our options are extremely limited. Guns and missiles are no good against a submerged target, and we can’t use ASROC missiles because of the ice cover. That leaves torpedoes.”
“Okay,” Ann said. “I’m still not seeing the connection. We don’t know anything about missiles, or torpedoes, or any of that stuff.”
“Our Mk-54 torpedoes weren’t designed for under-ice operations,” Chief McPherson said. “We’re concerned that acoustic reflections under the ice could prevent the torpedoes from finding their target. Specifically, we’re worried that the Mk-54’s active sonar will lock on to the ice keels that protrude from the underside of the ice pack, and attack them instead of the submarine.”
“I hope you don’t think we can answer that question,” Ann said.
“Not at all,” the chief said. “At the moment, no one can answer it. I’ve spent about three hours on the satellite phone with the torpedo engineers at Raytheon. They designed the Mk-54, and they don’t know the answer either. They’ll have to conduct extensive field tests to be certain, but they ran some quick and dirty computer simulations for me, and the results don't look good. Our torpedoes will probably not be able to locate the submarine in the under-ice environment.”
“That’s where your Mouse unit comes in,” the captain said. “We need it to go after the submarine under the ice pack.”
Ann was tired, and her weariness made her a little slower on the uptake than usual. So it took a few seconds for the meanings of the captain’s words to sink in.
She frowned, almost certain that she’d misunderstood him. “You’re saying you want to use Mouse … as a weapon?”
Captain Bowie shook his head. “Not exactly. What we need …”
Ann held up a hand. “Mouse isn’t configured for combat. He wasn’t designed to fight.”
“We know that,” Bowie said. “We don’t expect the Mouse unit to attack the submarine. That wouldn’t work. Your machine can’t carry a heavy enough explosive charge to guarantee a kill.”
“So what do you have in mind for Mouse?” Sheldon asked.
Bowie crooked a finger toward Chief McPherson, who laid an odd-looking device on the table top.
It was shaped roughly like a double-decker hamburger — round, with a domed top and a slightly concave bottom. It appeared to be constructed of metal and plastic. Several circuits and mechanical fixtures had been strapped to the outside using the red waterproof adhesive cloth that the Navy called ordinance tape.
“This is the acoustic transducer from a Mark-63 expendable mobile target,” the chief said. “The 63s are training tools. We toss them in the water, and let our Sonar Operators track them for practice. But in this case, we’re only going to use the acoustic section, so we pulled that part out and modified it.”
She pointed to the hodge-podge of add-on circuits. “It’s not pretty, but we’ve got it configured to respond to a coded external pulse. If we ping this thing with the right frequency, it kicks into beacon mode, and begins transmitting a loud acoustic signal that our torpedoes can track.”
“I’m totally lost,” Ann said. “Where does Mouse figure into this?”
Bowie spoke up. “The beacon has a magnetic base. We want Mouse to locate the submarine, and attach the beacon to its hull. Then, we need Mouse to come back out from under the ice and report back to us, so we know that the beacon is in place.”