Straits of Power

jagged, wriggling graph of intensity versus frequency from moment to moment. There were no signs at all of pure tonals that a submarine would give off, no mechanical transients, or anything else man-made.

Played at normal speed, from start to finish, the entire recording of the detection by the ocean rover lasted thirty seconds. There were a couple of breaks, where the sound disappeared and then began again two or three seconds later. Ilse guessed these were caused by jagged terrain in this relatively shallow stretch of the Mid-Atlantic Ridge, blocking the sound source from the ocean rover intermittently.

Ilse called up specifications on the ocean rover and its sonars. Unfortunately, the unit was too small and its hydrophones weren’t sophisticated enough to give her much with which to estimate the range between the rover and the sound — the whole rover was barely larger than a fat torpedo, and traveled at a mere four knots for long endurance.

The unidentified sound source was moving roughly north to south. She knew this because of how the bearing to the center of the sound changed with time, according to the ocean rover’s positional data. Knowing its range from the rover would help to indicate its speed. Its speed might help her figure out what it was.

She did more analyses. Eventually, from a variety of technical factors about how the power spectrum behaved, she narrowed down the source’s velocity to maybe thirty knots, minimum, and maybe a hundred knots, tops.

This was very fast, even too fast, for a sub or a decoy or a torpedo. The tonals would’ve been glaring…. And the signature was all wrong for a supercavitating rocket weapon. There was no sign at all of a missile engine firing, or exhaust bubble collapse, and anyway, those things went more like two hundred or three hundred knots.

Progress of a sort.

This sound is definitely a natural phenomenon of some kind.

Its intensity was stronger at lower frequencies — what acoustic engineers called gray noise. As an oceanographer Ilse knew the gray-noise quality was a sign suggesting that whatever had happened involved the displacement of rock or mud or lava. What was odd was that the fragmentary data she had did seem to imply — unless the navigational instruments on the rover were badly out of calibration — that the motion she was hearing was nearly horizontal, and its true velocity was almost constant. This didn’t make much sense among steep peaks atop an undersea mountain range, which was probably what had most puzzled METOC; other readouts Ilse examined and cross-compared said the ocean rover’s orientation and navigating were good.

Ilse struggled for hours, skimming research reports on tectonic behavior.

A slant-wise avalanche, she finally concluded. Ancient volcanic rubble, unstable from washing by eons of particle-laden current fronts, suddenly gave way, confined to a ravine so it slid sideways instead of falling straight down. It was known that the leading edge of such landslides could hydroplane, skating on a thin trapped layer of water, reaching at least fifty knots. Water resistance against the front face would keep it from accelerating much more than that…. After thirty seconds, the whole mess had rolled and bounced out of sound-path contact with the ocean rover.

It was obvious once you saw it. It had been right under the METOC peoples’ noses the whole time.

Felix Estabo was not a happy camper.

He and his men were running the same scenario for the fourth time. The first three times, he’d been killed.

The SEAL mission-rehearsal equipment aboard Ohio was superb. The virtual-reality capabilities of the helmets everyone wore far surpassed any video game the public could buy. Much of the software was so good it was rated top secret, and the system ran on Ohio’s supercomputer. The imagery looked completely real, and the detail of the scenario was astonishing. The compartment in which the rehearsal was played was temperature controlled, and fans created wind that affected trajectories of notional bullets fired inside the game. There were even sprinklers on the overhead to make real rain — which would show up on the pictures inside the game helmets too.

Each man stood on a treadmill, mounted on its own turntable, which sensed the speed and direction in which a player ran, and stopped if he stopped. The slope of the treadmill could vary constantly, depending on the terrain defined in the game and the player’s coordinates. It was able to imitate the physical effect of climbing stairs. The treadmill surface was wide enough for a man to lie prone, as if taking cover. Mechanical actuators underneath could also inflict the teeth-jarring, gut-pounding shock of a nearby artillery round or grenade.

The only thing lacking, Felix thought, were environmental odors.

A genuine battlefield stinks, even through a gas mask.

Since the CIA lacked much information on the safe house in which Peapod’s crucial equipment would be held — other than that it was some kind of house — Felix and Commander McCollough’s planning staff considered everything, and then did their best to prepare. Gerald Parker had brought data disks with building codes and architectural data for Istanbul. But as in any infiltration or forced-entry exercise, some types of structures and landscapes were easier or harder than others to penetrate.

The mission profile they were rehearsing now was intentionally made as difficult as possible. It involved a big mansion surrounded by a high wall, with a front and back gate protected by armed guards. The mansion’s exterior was stone, mostly granite or marble. This was based on an actual piece of real estate in Istanbul, something specific meant to represent one generic type.

The personality and voices of the mansion’s guards were played by SEALs from McCollough’s staff, all of whom had been in combat before. They pretended they didn’t know at first that Felix’s men were hostile, they just behaved in a careful, vigilant way.

And after dark on a Friday night, Felix thought, at a very wealthy person’s home, it can be hard to convince the guards we’re delivery boys or plumbers.

The SEALs communicated with the guards just as they would in actuality in Istanbul, using Portuguese- accented fractured English, improvised sign language — even notes, written in advance for the SEALs by someone who spoke good German, that Felix handed to the guards.

From previous run-throughs of this simulation, Felix had already decided that his team would have to kill all the guards, quickly and silently, before they could sound an alarm. The biggest risk was that real guards might be wearing life-sign monitors, which would transmit a warning if their respiration or heart rate fell outside the normal range. Jamming the transmissions would be guaranteed to alert every enemy in sight — or out of sight, inside the mansion, or elsewhere in a property holding backup troops. So transmissions had to be sniffed for in the ether, to know if monitors were worn by the adversaries on the perimeter. Then, if so, signals of fake live people — on the proper frequency — had to replace the real vital signs of the guards, seamlessly, as they died. Felix’s men came aboard Challenger with the portable equipment needed to do this. They were also trained in working down in utility manholes, to cut power and sever fiber optics on cue, to surprise and isolate their objective.

But past the guards was a wide lawn with no trees. It made a perfect killing field against intruders. Automatic weapons from the stone mansion had unobstructed arcs of fire… and the high stone wall and solid metal gates would stop the bullets from hitting elsewhere in the neighborhood. Such a lawn might have motion detectors, including pressure-sensitive strips hidden under the earth. These detectors would call the Kampfschwimmer to arms instantly, and might even set off booby traps to kill or wound the SEALs, or stun them for capture.

The team was prepared for this too. Probes could detect buried objects. Big rolled-up sheets of lightweight composites that flattened and became rigid under battery power would let the SEALs crawl through a field of buried mines if need be — but only assuming that the German traps weren’t set to be too sensitive, so as to avoid false alarms from stray cats or free-roaming guard dogs.

Then there was the safe house itself. Infrared visors helped penetrate walls to some extent, to identify body heat.

The technology list went on.

The gadgets and the tactics interrelate. They have to. Need dictates form and function.

Felix’s heart was pounding as the scenario played on. To him and his men, this was no game. The pretend assault was a matter of life and death, because soon the bullets and knives would not be make-believe.

Felix cursed to himself.

The defenses were too deep and strong. His team couldn’t push past the wall, and across the lawn, and inside the mansion without being seen and shot at while their only cover was hopelessly inadequate. Felix led from