The bomb sight picked out a cluster of trees on the far bank, the computer locked on, and seconds later, two more sensors ejected from the payload bay. Two of the ultrasensitive electronic listening posts were utilized at each site, just in case one malfunctioned. Pearson’s computers would accept the incoming signals, identify the sending sensor, define the direction of travel on the river, and compile a log of traffic. Additionally, the frequencies and resonances involved helped the computer to determine the approximate size of the watercraft.
“Can I have my airplane back, Tiger?”
“This hummer’s all yours, jefe.”
Feeling pretty good about himself, McKenna clicked his visor into place, automatically turning on the oxy/nitro feed. He retracted the bomb bay doors, then shoved the jet throttles forward to their stops and raised the nose with the hand controller. Ahead was about twenty miles of nearly deserted area, with few people to hear any increased output from the MakoShark’s twin turbo jets. The MakoShark responded with her typical agility. He took her up to 7,000 feet before she cracked the sound barrier. The sonic boom would echo through the forests and perhaps frighten a few folks out of their sleep.
Tough shit.
The HUD velocity readout had changed to Mach numbers and was displaying Mach 2.5 when they crossed the northern coast in clear skies at 50,000 feet over Rostock. The lights of shipping in the Baltic Sea winked merrily. Far to the east, the pale light of dawn was creeping toward them.
“Want to go north, Tiger?”
“Until we go south.”
“I’m switching over.”
“Do it to it.”
McKenna activated the rocket control panel and checked the readouts. The two rocket motors operated on solid-fuel propellant and were considerably safer than liquid-fueled engines. The drawback to solid-fuel rocket motors had always been the lack of control. Typically, the solid fuel was encased in a cylinder, and once ignited, burned at a steady rate, raising pressures and exhausting through a nozzle, until the fuel was expended. For the MakoShark, the designers had developed a pelletized solid fuel which was stored internally in wing-mounted tanks. Under the pressure of compressed carbon dioxide, the pellets were forced into the combustion chambers at a rate determined by the opening of nonblow back valves. The valves were actually the throttle control, and McKenna could vary the thrust output from 55 to 100 percent, from 68,000 to 125,000 pounds of thrust on each of the two rocket motors.
Munoz double-checked him, following the checklist the WSO had put up on the rearview screens.
“Fuel supply?”
“Nine-point-five thousand pounds,” McKenna said. “Almost full up, and showing two-one time.”
“CO-two reserve?”
“Twelve thousand pounds PSI.”
“Igniter test?”
“Testing. Got one, got two… now three and four.”
“Activate igniters one and two.”
McKenna flipped the toggles for the primary igniters in each of the rocket motors. Three and four were backup systems.
“Igniters are live, Tiger.”
“Open CO-two valves.”
McKenna opened the valves, pressurizing the solid-fuel pellet tanks.
“Done.”
“Activate throttles, Snake Eyes.”
“Active.”
“Throttles at standby position.”
He pushed the outboard throttle levers to their first detents. Pulling them farther back killed the motors.
“Throttles in standby,” McKenna reported.
“Comp Control?”
“Punching in six-five percent.” McKenna touched the pad in the top row of buttons that read “RKT THRST,” keyed in the six and the five, stored the data, then tapped the “STDBY” pad.
“Go for it.”
Pushing the throttles to the next detent, McKenna started the fuel flow.
The response was immediate, and he felt himself pushed back in his seat. Green flashes on the HUD showed both motors had come to life.
“I have ignition,” McKenna said.
“Copy. Let’s cruise.”
McKenna keyed in the final command for the computer, hitting “RKT THRST” a second time, then watched as the throttles moved forward on their own. He could always override the computer manually, but the computer had the ability to keep the rocket motors generating the same amount of thrust, preventing the craft from slewing to one side or another. Moments later, the thrust readout showed 81,200 pounds on each motor, the velocity readout was climbing to Mach 4, and the altimeter was spinning upward through the numbers. Sixty thousand feet, 70,000 feet, 80,000.
McKenna was forced back into his seat as the gravitational force rose to 3.8.
He killed the turbo-ram jet engines at 110,000 feet. In either turbo or ram mode, the atmosphere was too thin for engine operation.
At 150,000 feet, McKenna leveled out and commanded the computer to reduce thrust to 60 percent. The MakoShark was cruising along at Mach 5.5. Almost 4,000 miles per hour.
The G-forces began to drop off.
Four minutes into the burn, he pulled the rocket throttles all the way back to kill the motors. The rockets used fuel at a prodigious rate, consuming the entire five-ton fuel load in twenty-four minutes at 90 percent thrust. When operating for long distances in suborbital altitudes, from 100,000 to 300,000 feet, the rocket motors were used intermittently. Since he had not used full thrust for this burn, the time available indicator for the rocket motors now read 17.4 minutes.
The sun was fully up at their altitude, but McKenna could see the line of darkness on his right. The curvature of the earth was discernible in the east. Above and on his left, the sky was a dark purple. At higher altitudes it would go black, a perfect carpet for the sharply lit starscape. Where there was no cloud cover in place, the lights of cities blinked like earthbound stars.
There was no sound, one of the delights McKenna found in high altitude, multisonic flight. He felt suspended.
“I don’t know about you, Kapitän, but I think my day’s already been made. I’m gonna sleep for the rest of it.”
“And miss the rest of the trip?”
“It’s a short one, anyway. Wake me when it’s over.”
McKenna had no doubt that Tony the Tiger would be in a coma within two minutes. He could sleep anywhere.
McKenna keyed in the coordinates for Peterson Air Force Base and let the computer work out the navigation, allowing for the parabolic downward curve of their glide. The navigational computer was in continual contact with three or more of the eighteen NavStar Global Positioning Satellites in orbit which triangulated the MakoShark’s location. The GPS helped the computer to establish their latitude, longitude, altitude above mean sea level, velocity, and ground speed. The accuracy level was correct to within a few feet of position and a half mile of speed.
In a direct line of flight over the top of the world — actually passing 800 miles south of the north pole, over Greenland, their target in Germany was located slightly over 5,000 miles from their destination in the middle of Colorado. With two rocket boosts en route and an average speed of Mach 5, the computer estimated that Peterson was now ninety-one minutes away. The computer made pretty accurate guesses.
Dialing one of the backup radios into a satellite relay channel, McKenna found an oldies rock station and “Sleepwalk” filled the earphones built into his helmet.
The Arctic ice pack was eerily beautiful, not totally white, but streaked with blue-shadowed crevices. From this altitude, it looked inviting, smooth and receptive. Deceptive, too, McKenna knew.
They crossed the U.S. border a few miles east of Grand Forks, North Dakota, at 80,000 feet.