“Dirk doesn’t need us. If anyone can damn well explode that bomb and park Big Ben on the shore, he will.”
“My money is on him too,” Sandecker said with total conviction.
“Okinawa?” Turner asked, his hand tightly gripping the controls.
Very slowly, with much difficulty, as if he were fighting the devil for his soul, Sandecker looked at Turner and nodded. “Okinawa.”
The big aircraft banked on a new course and limped into the darkness. A few minutes later the sound of its engines faded, leaving behind a silent sea, empty but for one man.
71
WITH THE BOMB hanging grotesquely from its manipulators, Big Ben sat poised on the edge of the great submarine trench that yawned ten kilometers wide and two deep. Inside, Pitt stared grimly down the slope that trailed off into the gloom.
The geophysicists had selected a point about twelve hundred meters below the rim of the trench wall as the optimum location for the blast to set off a landslide that would in turn launch the seismic sea wave. But the grade was a good five percent steeper than the satellite photos had suggested. And worse, much worse, the upper layer of sediment that formed the sides of the trench was the consistency of oily clay.
Pitt had activated a telescoping probe into the silt and was far from overjoyed at the geological test results that read across the computer screen. He realized the danger of his position. It would be a battle to prevent the heavy vehicle from slithering through the slick muck all the way to the bottom of the trench.
And once he was committed and plunged Big Ben over the edge, there was no turning back. The cleats on the drive tracks could never gain a grip solid enough to pull the DSMV back up the slope and over the ridge to safety before the explosion. After priming the bomb, he decided to continue on a diagonal course downward along the side of the slope, much like a skier traversing a snow-packed hill. His only chance, and a slightly less than nonexistent one, was to use gravity to increase his speed and push Big Ben beyond the clutches of the avalanche before they were both caught up in its force, swept away, and buried for the next ten million years.
Pitt appreciated how narrow the fine dividing line was between survival and death. He thought wryly that Murphy’s Law never took a holiday. He missed having Giordino at his side and wondered why all communications had ceased from the C-S Galaxy. There had to be a good reason. Giordino and Sandecker would never desert him without cause. It was too late now for explanations and too early for final farewells.
It was eerie and lonely with no human voice to prop up his morale. He felt the fatigue sweeping over him in great woolly waves. He slumped in his seat, any optimism drained away. He examined the coordinates for the detonation site and peered at his watch for the last time.
Then he took manual control of Big Ben, engaged the forward drive, and plunged the huge tractor vehicle down the steep slope.
The momentum rapidly increased after the first hundred meters, and Pitt began to doubt he could stop DSMV before it barreled to the bottom of the trench. He quickly discovered that braking the treads failed to check his speed. Friction did not exist between the cleats and the slick mud. The great mechanical beast began to slide over the slick surface like a runaway truck and semitrailer hurtling down a steep road grade.
The rotund bomb swung wildly in the grip of the manipulators. Because it hung directly in front of his forward view, Pitt could not avoid glancing at the evil thing without conceding it in his mind’s eye as the instrument of his own impending death.
Suddenly another terrifying thought mushroomed in his mind. If it broke free and rolled down the slope, he might never be able to retrieve it. He stiffened in desperate fear, not of death, but that he might falter in the home stretch.
Pitt moved quickly now, uncaring that he had taken a risk no sane man would ever have contemplated. He slipped the drive into reverse and applied extra power. The cleats wildly thrashed through the slippery ooze backward, and Big Ben sluggishly slowed to a crawl.
A wall of silt engulfed the vehicle as he brought it to a full stop. He waited patiently for visibility to return before easing forward for fifty meters, then engaging reverse and drawing the DSMV to a halt again. He continued this series of maneuvers until he regained firm control and had a feel for the interaction between the drive track and the mire.
His movements at the controls became hurried now. Each passing minute increased his desperation. At last, after nearly thirty minutes of intense effort to move the big DSMV where he directed it, the navigational computer signaled that he had reached his destination. Thankfully, he found a small level shelf protruding from the slope. He disengaged the power systems and parked.
“I have arrived at the detonation site and will begin to arm the bomb,” he announced through his communications phone in the forlorn hope Sandecker and Giordino might still be listening in somewhere above.
Pitt lost little time in lowering the manipulator arms and setting the bomb in the soft sediment. He released the grippers and interchanged the pincers for working tools. Once more he inserted his hand into the manipulator control and very carefully used a sheetmetal shear to cut away the panel on the tapered tail assembly that covered the main fusing compartment.
The housing inside contained four radar units and a barometric pressure switch. If the bomb had been dropped as planned, the radar units would have bounced their signals off the approaching ground target. Then, at a predetermined altitude, an agreed reading by two units would send the firing signal to the fusing system mounted on the front of the implosion sphere. The second arming system was the barometric switch that was also set to close the firing circuit at a preset altitude.
The firing signal circuits, however, could not be closed while the plane was in flight. They had to be triggered by clock-operated switches that were not bypassed until the bomb had dropped well clear of the bomb bay. Otherwise Dennings’ Demonswould have gone up in a pre-detonated fireball.
After the panel was removed, Pitt swiveled a miniaturized video camera on the end of the left manipulator. He quickly found the barometric arming switch and focused on it. Constructed of brass, steel, and copper, it showed signs of corrosion but was still intact.
Next, Pitt coupled a slender three-pincer hand to one manipulator. The arm was flexed back toward the front of the DSMV, where the pincers opened the heavy mesh lid of a tool crib and removed a strange ceramic object that looked like a small deflated soccer ball. A copper plate was imbedded in the concave bottom, surrounded by a pliable bonding material. The appearance was deceiving. The object was actually a very sophisticated pressurized container filled with an inert puttylike compound composed of plastic and acid. The ceramic cover surrounding the caustic substance had been contoured to fit snugly over the barometric firing switch and form a watertight seal.
Pitt worked the manipulator hand and positioned the container around the switch. Once it was firmly in place, he delicately pulled a tiny plug that allowed the sea to seep very slowly into the container. When the inert compound inside came in contact with saltwater, it chemically turned active and became highly caustic and corrosive. After eating through the copper plate—the thickness governed a delayed sequence of one hour—the acidic compound would then attack the copper in the barometric switch, eventually creating an electrical charge that would set off the firing signal and detonate the bomb.
As Pitt retracted the manipulators and gently backed Big Ben away from the hideous monstrosity lying like a fat, slimy bulge in the mud, he stole a quick glance at the digital clock on his instrument console.