The Bin Laden Plot

46 ALVIN

Alvin descended through the darkness, continuing its trek toward the ocean floor nine thousand feet below the water’s surface. Inside the submersible, it was quiet at first, the only sound being the hum of the carbon dioxide scrubbers purifying the air, until Hillsley turned on music, which was now playing softly in the background. The external lights were kept off during the descent, saving the vehicle’s battery power until they reached the bottom. What they were searching for hadn’t been fully explained to Hillsley — and wasn’t going to be — although Christine wondered if he had deduced the reason for their mission. After all, bin Laden’s burial in the Arabian Sea was public knowledge.

If Hillsley suspected, he didn’t let on, spending the time instead monitoring Alvin’s equipment, including its scrubbers and oxygen bleed, ensuring the air inside the sphere was properly maintained. Everything was functioning properly, and Hillsley eventually struck up a conversation, during which Christine learned a great deal about Alvin and the fascinating sea life surrounding them.

The first two hundred meters of their descent was through the euphotic zone, also called the sunlight layer, where enough light penetrated the water to support photosynthesis and where the majority of aquatic organisms lived. The light outside faded, becoming greenish at first, gradually transitioning to dark blue. After ten minutes, they entered the dysphotic or twilight zone, where only a small amount of light penetrated, and Christine watched as numerous glowing bioluminescent animals floated past Alvin’s portholes.

Darkness then closed in as Alvin entered the aphotic — or midnight — zone, devoid of natural light. Inside the submersible, the only light came from blinking LEDs built into the sophisticated electronics. Outside the submersible, occasional greenish flashes were emitted by small fluorescent marine animals disturbed by Alvin’s descent through their realm.

It was cold inside the sphere; the temperature had plummeted due to the near-freezing seawater surrounding them. A chill set in, and Christine put on a sweater and pair of jogging pants she had borrowed from one of the crew members aboard Atlantis, following the advice of Alvin’s operations officer.

As they descended, Hillsley monitored Alvin’s sonar display for the sonic beacon in bin Laden’s body bag. To conserve power, the beacon emitted a pulse only once every hour. The pulse had been detected by the sonar equipment aboard Atlantis, so they knew it was functioning and they were in the right spot. Still, even a small angular error in a nine-thousand-foot descent could place Alvin far from their objective once it reached the ocean bottom.

About halfway down, Hillsley picked up a pulse from the beacon and made a slight adjustment in their downward trajectory, energizing one of Alvin’s seven thrusters for a few seconds.

As predicted, it took ninety minutes to complete the descent. As they approached the ocean bottom, Hillsley turned off the music and energized additional equipment, including its external lights, illuminating a flat, featureless, sediment-covered bottom out to a range of about thirty feet.

Christine peered out one of the five viewports; there were three in the forward portion of the sphere, each about seventeen inches in diameter, with a smaller, twelve-inch-diameter portal on each side. Additionally, there were three small displays mounted to the equipment racks, connected to cameras mounted to Alvin’s exterior.

Hillsley set Alvin to hover ten feet above the ocean floor. While they awaited the next sonic pulse from bin Laden’s body bag, they searched the immediate area, doing a slow spin at their current location. Hillsley examined the results from three different sonars: two seafloor profilers, plus a dual-frequency scanner that could detect objects buried down to forty feet beneath the ocean floor.

About the time they finished searching their current location, Alvin received another ping from the sonic beacon, coming from a bearing of zero-one-one. Hillsley set Alvin to the northerly course, proceeding slowly. Although the submersible was capable of a speedy two knots, Hillsley explained that they typically cruised along the bottom at only one-half knot to preserve battery power. As they traveled toward the object, Christine directed Hillsley to de-energize Alvin’s cameras. She wanted no recording of what was about to occur.

They crept slowly above the ocean floor, with Hillsley monitoring the three sonar displays, until an object was located almost directly ahead — a small, gently sloping protuberance on the otherwise flat bottom. Hillsley shifted the fore-aft thrusters to reverse, stopping Alvin just before the bump.

Alvin was well equipped for tonight’s task, with a tube corer in one of the submersible’s claws, although it was much smaller than the standard corers used by Hillsley in the past, since its purpose was to take a small tissue sample once it pierced the body bag. But first, they had to clear a path to whatever lay beneath the ocean sediment.

Hillsley activated a suction tube used for taking sediment or organic samples, set to discharge instead of suction. In its current configuration, it worked like an underwater blower, clearing the sediment away as Hillsley moved it back and forth with Alvin’s other manipulator. A black speck beneath the sediment appeared, growing larger as more material was blown away. The intense sea pressure had compressed the plastic bag around its contents, and the outline of a body became evident, lying atop a set of chains and beside a spherical object that must have been the sonic beacon.

Hillsley asked no questions as he prepared the corer in the manipulator’s right claw. He turned to Christine, who simply nodded. He inserted the corer through the bag into the corpse, then withdrew the corer with its sample and placed it into a bio box staged in the submersible’s storage bin.

Once the bin was secured, Hillsley dropped several hundred pounds of iron weights from the DSV to begin the ascent. As they rose, Alvin’s lights illuminated the body bag until it faded into the darkness.