To understand this Catch-22, assume for a moment that your household flashlight is a radar beam. Now then, sit in a darkened room and hold up an ace of spades playing card and shine the light on it. The light hits the card and is reflected back into your eyeball. Held face toward you, the card is easy to see.
A radar beam works on much the same principle. When its electronic signal hits a reflective surface, it bounces back to the receiver and shows up on an operator's green screen. In electronic parlance, this reflective surface is called Radar Cross Section, or RCS. The ace of spades turned broadside toward the path of the light beam presents a highly reflective surface, or high RCS.
Now then, take the ace of spades and turn it sideways, then shine the flashlight on it.
It now has a low RCS and is much harder to see, and the same dynamic applies to radar. To be invisible, simply present an extremely low RCS to the enemy radar transmitter.
Simple in theory. Difficult in practice. Particularly for a bomber, because by their very nature bombers tend to be a tad bulky. Items like the tail section, the fuselage, the jet engine pods, and the spinning turbine blades, all produce a beautifiilly high RCS. To design a bomber that was invisible to radar, the aeronautical engineer had to eliminate, reshape, or cloak these fundamental parts — and that was a sticky problem.
It took fifteen years, $22 billion, and several crashes before Northrop produced a reliable production prototype, but it was, at long last, achieved.
The stealth bomber was shaped like a boomerang with a jagged trailing edge that truly did give it the appearance of a bat-wing. The body of the winglike structure was smooth, except for the crew compartment and air intake nacelles which rested on the top side of the aircraft in pods that tapered into the skin. The single-wing design and tapered pods reduced the aircraft's cross section and allowed radar beams to "roll over" the aircraft. And to further enhance its low RCS, the bomber's skin was not made of metal, but of intricately patterned anechoic carbon fiber composites which absorbed — rather than reflected — radar energy. Additionally, the entire exterior of the plane was painted with a substance called retinyl Schiff base salts, which further enhanced the absorption of radar waves.
To conceal the spinning turbine blades from radar, the air flow traveled from the topside air intake nacelles into a set of S-shaped ducts that funneled the air into the four General Electric F118-GE-100 engines. The GE power plants did not hang from exterior wing pylons as on a commercial airliner, but were implanted into the body, further reducing the cross section.
Although it possessed ailerons and elevators along its trailing edge for banking, climbing, and diving, the stealth bomber had no vertical tail stabilizer with a rudder for turning. Instead, it used "drag rudders" on the trailing edge of each wingtip. If the pilot wanted to turn right, the right drag rudder would deploy like an air brake and the air resistance would pull the right wing-tip to the rear, thus putting the aircraft into a right turn. But flying without a tail stabilizer could create an inherently unstable aeronautical situation. And to compensate for this, the stealth bomber was absolutely lousy with computers, possessing a General Electric quadruplex digital flight control system. This system could sense the instability of the aircraft, then compensate on the control surfaces to keep it flying in accordance with the pilot's direction.
Although stealthy, the flying batwing was not small. Its wing-span was only slightly less than a B-52's, and it could carry an ordnance load of up to fifty thousand pounds in its two tandem weapons bays along the aircraft's center line.
The aircraft was not invisible to radar in the absolute sense of the word. Rather, its RCS was reduced to the point that it was no bigger on an enemy radar screen than a ringtail hawk. Unless the search radar had been tweaked to a high degree of sensitivity and the radar operator was experienced with stealth radar "signatures," then for all practical purposes, the bomber could not be detected until it was within twenty to twenty-five miles of a radar transmitter. For an aircraft travelling at 500 mph, that would mean about three minutes' warning.
The central hump that covered the cockpit sloped up from the nose at a low tapering angle, forcing the crew seats to be set back a good distance from the leading edge of the plane. This impaired the pilot's field of vision, and to compensate for it, the stealth bomber was given a large wraparound windshield and three television cameras mounted just under the nose.
The crew was configured in some respects like that of an FB-111 or an A-6 Intruder — just two people. The commander of the aircraft was the pilot in the left seat, while the person on his right was the electronic systems officer. The ESO was a navigator, bombardier, and communications/electronic warfare officer all rolled into one; and he was invariably referred to as "Whizzo."
"Authentication signal coming through now, Skipper," said the ESO.
The message, which had originated in the Pentagon, traveled to SAC headquarters in Omaha via fiber-optic cable, then was relayed to Ghost Leader's aircraft by a Milstar communications satellite. The encrypted message came through the Oracle scrambling system and was automatically stored in the commo panel's microchip brain. The ESO could call up the encrypted message on the commo panel's small digital display, but he preferred to work from the paper tape. He punched a button and the thermal printer quickly rolled out the hard copy of five-digit code groups. Working from a notebook on a tummy-level desk board, he quickly decoded the message from a one-time pad. It read: thor's hammer. He ripped the message from the pad and handed it to his pilot. Ghost Leader and the ESO each withdrew a sealed envelope from his own flight suit, ripped it open, and extracted a plastic 3-by-5-inch card with printing on it. The message — and the two plastic cards — all read thor's hammer.
Ghost Leader was a pro. A full colonel who'd been in SAC for twenty-three years and was the chief test pilot on the stealth bomber development program. His hair was gunmetal gray and his face deeply lined. Yet despite all his experience and the years and years of training, nothing quite prepared him for such a moment as this. His throat felt dry and he gulped. Hoping his voice sounded reasonably confident, he said to the ESO, "I authenticate Thor's Hammer."
"Confirm," echoed the ESO — a major who was somewhat in awe of the veteran pilot and didn't detect any nervousness in the older man's voice. "I authenticate Thor's Hammer."
Ghost Leader gulped again and said, "All right, Whizzo, let's proceed to the holding station. We'll wait there for a go or abort signal. How far to the Soviet border?"
Whizzo took a glance at his Global Positioning System. The bombers were still in Iranian airspace. "A hundred twenty-three nautical miles to the Russian border, Skipper."
"Okay," said Leader evenly. "Is the laser channel open to Ghost Two?"
"Hold on," said Whizzo, while twisting a hand controller.
A problem often encountered by aviators on combat missions was die nettlesome requirement that they maintain radio silence. Ships at sea could sometimes get around this nuisance by using blinker signal lights, but aircraft could rarely resort to such a time-consuming technique. So to remedy that shortcoming, Ghost Leader's bomber possessed a communications laser beam on its belly. The beam could be aimed at a receiver grid on the dorsal side of his wingman's aircraft. Secure voice communications could travel back and forth between the two bombers as long as the laser beam could stay aligned with the receiver grid— and that was the tricky part. Keeping the beam on a three-square-foot grid while the two aircraft lumbered along at 500 mph was a bitch. Ghost Leader and Ghost Two were about three hundred feet apart — Leader on top and Ghost Two below in a "stacked" formation. The two aircraft maintained enough distance to prevent them from forming a discernable radar signature, but were close enough to allow the ESO to aim the laser beam with his hand controller.