A new missile threat was also emerging. Development work was under way on the R-7 intercontinental ballistic missile (ICBM). A new test site, in Soviet central Asia, was completed in late 1956. In March 1957, the prototype R-7 was undergoing checkout. The missile was fired on May 15 but exploded fifty seconds after launch. Two more launch attempts were made in the spring and summer, also ending in failure.
These activities were detected, and Eisenhower authorized a series of overflights to find the launch site. These overflights were along the main railroad lines. During one of them, the pilot spotted construction in the distance and altered course to photograph it. When the photos were developed, they showed the launch pad. Within days, the analysis was completed. The site was named "Tyuratam," after the rail stop at the end of the fifteen-mile spur that connected the site to the main Moscow-Tashkent line.
The string of R-7 failures ended on August 21, 1957, when the fourth attempt made a successful 3,500-nautical-mile flight. A second successful R-7 launch followed on September 7. Emboldened by the twin flights, Communist Party Secretary Nikita Khrushchev authorized the launching of an earth satellite by an R-7. This was Sputnik 1, orbited on October 4, 1957.
Sputnik 2, which carried a dog named Laika, followed on November 3.[84]
The R-7 and Sputnik launches showed the Soviets had achieved a breakthrough in rocket technology. Estimates began to appear that the Soviets would deploy their ICBMs, which had been given the NATO code name SS-6 Sapwood, in huge numbers. If true, the United States would be vulnerable to a surprise nuclear attack. So began the "missile gap" controversy. Unlike the bomber gap, this new intelligence question was not so easily answered.
The Soviet Union was vast. Even with the use of bases in Iran, Pakistan, and Norway, many areas were out of the U-2's range. Another factor was Eisenhower's growing reluctance to authorize overflights. He feared that large numbers of such flights would provoke the Soviets, possibly starting World War III.[85]
What overflights were authorized concentrated on Soviet rail lines. Because of the SS-6's huge size, it could only be moved by rail, and any operational sites would also be located near rail lines. The problem was the U-2s were failing to bring back any photos of deployment. No ICBMs were spotted in transit, nor were any operational sites found. Despite this lack of evidence, the air force continued to insist that the Soviets would deploy large numbers of SS-6s.
Eisenhower was increasingly frustrated. From the U-2 photos, he knew Soviet nuclear forces were a pale shadow of those of the United States, but without evidence of the true SS-6 deployment rate, he was attacked as downplaying the Soviet threat in order to balance the budget. To aggravate matters, Khrushchev was using the missile gap and Soviet successes in space to promote an image of superiority. This, in turn, was used to put pressure on the West over Berlin.[86]
While the overflights were under way, the Ranch housed the headquarters squadron, called Detachment D, and the training unit for the first group of air force U-2 pilots.[87] The Ranch also served as Lockheed's U-2 flight test center. Starting in late 1956, work was under way on a program that would influence the design of every Dark Eagle to follow and that would see final success two decades later.
When the U-2 was first developed, it had been hoped that the aircraft would fly so high the Soviets would have only fragmentary tracking data and would not be sure what was going on. During training flights, this theory had been borne out: only one or two radar sites would detect the aircraft. When the overflights started, however, the Soviets were not only able to track the U-2s but vector fighters toward them.[88]
President Eisenhower was extremely disturbed by the ease with which the Soviets were detecting the U-2 overflights. He directed that work be undertaken to reduce the U-2's "radar cross section." Called Project Rainbow, it had the highest priority and the attention of all the Skunk Works engineers. Eisenhower threatened to end the overflight program should Rainbow fail. Johnson asked advice from two radar experts, Dr. Frank Rogers and Ed Purcell.
They suggested stringing wires of varying lengths from the nose and tail to the wings. The idea was to scatter the radar signals away from the receiver, which would weaken the radar echo. The modification worked, but with major shortcomings — the U-2's range was cut and its maximum altitude was reduced by seven thousand feet. The wires also whistled and sometimes broke, flapping against the cockpit and fuselage.
The other attempt was more elaborate. The U-2's underside was covered with a metallic grid, called a Salisbury Screen, and then overlayed with a black foam rubber called Echosorb. The grid would deflect the radar signal into the absorber. The modifications proved to have only limited usefulness.
At some radar frequencies, they did reduce the U-2's radar cross section. At others, however, the plane's radar echo was made worse. The coating also prevented the engine's heat from dissipating out the skin.
This latter problem caused the loss of Article 341, the U-2 prototype. On April 4, 1957, Lockheed test pilot Bob Sieker was making a flight at 72,000
feet. This involved flying the aircraft up and down a radar range for hours on end. The heat buildup caused the plane's engine to flame out. When this happened, cockpit pressurization was lost and Sieker's suit inflated. As it did, the clip holding the bottom of his faceplate failed and it popped open.
The suit lost pressure, and Sieker passed out within ten seconds. The U-2 went into a flat spin and crashed.
A search was launched, but the wreckage could not be found. It was Lockheed test pilot Herman "Fish" Salmon who discovered the crash site.
He rented a twin-engine Cessna from Las Vegas, and three days after the crash, Salmon found the U-2 in a valley near Pioche, Nevada, about ninety miles from the Ranch. The faceplate was still in the cockpit. Sieker's body was fifty feet away. This suggested that he had revived at the last moment and jumped from the plane but was too low for his parachute to open. In the wake of this and other accidents, an ejector seat was added to the U-2. (In June 1957, following the crash, Lockheed moved its test operations from the Ranch to North Base at Edwards Air Force Base.)[89]
Finally, Johnson decided it was more practical to cover the aircraft with a paint that contained iron ferrite. Later called "Iron Ball" paint, it absorbed some of the radar signals, which reduced the cross section by an order of magnitude.
The first "Dirty Bird" U-2, as the modified aircraft was called, was sent to Turkey in July 1957. It had wires strung from the nose to poles on the wings, as well as the radar absorbing paint. On July 7, CIA pilot James Cherbonneaux made a Dirty Bird flight along the Black Sea coast to probe Soviet air defenses. Intercepted communications indicated the wires and coatings worked well but that the Soviets were able to pick up radar returns from the cockpit and tailpipe. Two weeks later, he made a Dirty Bird overflight of the central Soviet Union from Pakistan. It covered Omsk and the Tyuratam launch site, before landing back in Pakistan.
In the end, the loss of altitude caused by the wires was too great and they were removed. The Iron Ball paint continued to be used. At first, it was a light color. This was soon changed to midnight blue, which matched the color of the sky at 70,000 feet. This would make it harder for MiG pilots to […] appearance.
With the failure of the Dirty Bird U-2, it was now clear to Johnson that a reduced radar cross section would have to designed into a plane from the start, not added on later. Ironically, when final success was achieved, Johnson was one of those who doubted it could work.
88
89
Pocock,