The SR-71, and its CIA-operated single-seat predecessor, the A-12, barely resembled an aircraft on first glance. The huge black jet appeared to be more of a spacecraft or at least a winged missile than one of the greatest high-performance production jets in the world.
Developed as a replacement for the U2 spy plane, the SR-71 was designed from the beginning to be able to outfly anything put up against itâbe it aircraft or missileâfor at least several decades from its first introduction. As a strategic reconnaissance aircraft, the SR-71 has yet to be bettered more than fifty years after its introduction. It is a high-performance camera platform, even more effective than an orbiting spy satellite for some missions. With its two-man crew, the cameras of an SR-71 can cover an area of 110,000 square miles per hour of flight at 82,000 feet. That gives the craft the capability of photographing the entire United Kingdom in less than an hour while on a single mission. And the detail the cameras can make out is such that a golf ball can be resolved on the ground from 80,000 feetâabout a 1.7-inch sphere seen from more than 15 miles up.
To protect itself, the SR-71 operates on the very edge of space; altitudes of over 82,000 feet are normal for an operational flight. The speed that the craft can move at is also a major part of its success; the SR-71 is capable of cruising at Mach 3 to Mach 3.5âthree to three and a half times the speed of sound, or from 2,280 to 2,660 miles per hour. At top speed, the Blackbird covers a mile on the ground in less than one second, over 3,300 feet per second, literally faster than a speeding bullet.
At 82,000 feet altitude, the air is a killing -69 degrees Fahrenheit and is so thin that it only exerts a pressure of 0.4 pound per square inch, as compared to 14.7 pounds per square inch at sea level. The environment would kill an unprotected human being in seconds if they were exposed to it. The SR-71 was designed to operate at its best in this same environment. But special problems had to be addressed when designing the craft to make sure it worked at its intended flying speeds.
In spite of the thin air and subfreezing temperature at altitude, structural parts of the SR-71 can be heated to 600 degrees Fahrenheit by just the friction of the plane flying at a modest Mach 2.4, which equals one mile every two seconds. Because of this and other factors, the bulk of the SR-71 was built of titanium alloys. The titanium skin of the jet helps protect the aluminum airframe components from the heat that would otherwise melt them in flight. It was the first aircraft ever to be built of such special materials, the fuselage being 93 percent titanium alloys and composite materials. It paved the way for the future family of stealth aircraft.
The SR-71 itself is basically a flying fuel tank with engines, except for a little room allowed in the design for sensors and crew. The most dominating outside feature of the craft, besides its sinister black shape, are the two huge Pratt & Whitney J58 engines that each develop 32,500 pounds of thrust. The huge engines were specially designed in the precomputer age of slide rules and pen-and-paper engineering to operate effectively at high altitudes and speeds and made the SR-71 the fastest and highest-flying air-breathing jet in the world for most of its operational life.
The craft that would become the SR-71 was first flown on December 22, 1964, and entered service with the U.S. Air Force under the Strategic Air Command in January 1966. Just fewer than thirty of the craft were built in the 1960s; at the time, the cost per copy was $34 million.
The crew for an operational SR-71 was made up of a pilot in the front seat and a reconnaissance systems operator (RSO) in the rear. Though a fully qualified pilot himself, the RSO did not operate the aircraft. The rear seat in the cockpit did not have a set of flight controls, through there were a number of instruments there that enabled the RSO to assist the pilot in managing the SR-71's systems. Instead, the RSO ran the cameras, radar suite, and the rest of the sensor systems to carry out the basic reconnaissance mission of the aircraft.
Prospective crewmen who wished to serve in SR-71s had to have at least 2,500 hours in the air on standard aircraft before they would be allowed to volunteer for the training program. The cost and rarity of the aircraft meant that only the most technically proficient people were allowed to operate the unique craft. Additionally, the secrecy of almost every operational flight of an SR-71 meant that those who manned one of the great black birds had to be among the most trustworthy in the Air Force. The physical demands of flying on the edge of space in a high-performance aircraft also required a high level of fitness to survive the missions and bring the bird, and the crews, back alive.
The required near-perfect professional performance reviews of prospective volunteers would be carefully examined while the men themselves underwent a battery of medical tests and deep-background checks. Even after all of these requirements had been met by those wishing to serve in SR-71s, they still had another high hurdle to pass. The selection board that interviewed each volunteer was made up of people who already actively manned the aircraft. They knew best just what the demands were on a person, both physically and mentally, when flying Blackbirds. Because of this unique knowledge, the opinion of the selection board was given a good deal of weight when it came time to finally allow a specific volunteer into the training program.
An initial deployment to Asia of the A-12 proved the value of such an asset in obtaining photographic intelligence of enemy sites. In May 1967, it was put out in high-level intelligence briefings that the North Vietnamese were going to be fielding missiles that could greatly escalate the conflict. The director of the CIA stated that the A-12 was invulnerable to Soviet-made antiaircraft missiles and would be the proper aircraft to conduct surveillance of North Vietnam. The plan to deploy the craft was approved by President Johnson himself and A-12 aircraft were quickly deployed to Kadena Air Base on Okinawa as Operation Black Shield. The first operational flight over North Vietnam took place on May 31.
The A-12 and subsequent SR-71 both proved too difficult to hit by any of the dense North Vietnamese air defenses. Over the most heavily defended airspace in the world, the closest any of the aircraft came to being hit was when a very small piece of brass from the fuse of an SA-2 “Guideline” missile was discovered imbedded in the aircraft's skin in an after-flight inspection. The SA-2 missile has a maximum range of about 31 miles, an altitude ceiling of 80,000 feet, and a maximum speed of Mach 3.5. The 287-pound high-explosive warhead of the missile caused no damage, but left the pilot with a very interesting souvenir. It was the closest thing to a hit on an A-12 or SR-71 in more than 1,000 flights over enemy territory.
The SR-71 took over from the A-12 aircraft at Kadena in early 1968. The CIA-run overflight program was closed and the Air Force in the form of the Strategic Air Command (SAC) took over the reconnaissance mission previously done by the Agency. As an SAC overseas reconnaissance station, the Kadena SR-71 detachment became known as Operating Location 8 (OL-8).
The stationing of the SR-71s at Kadena resulted in something that followed the crews and aircraft for the rest of their existenceâbesides their amazing record of accomplishments. Though referred to publicly as the Blackbird, crew members preferred the nickname that was conferred on the craft soon after their arrival in the Okinawa area: Habu. The Habu is a dark-colored poisonous snake indigenous to the islands that make up the Okinawa area. Locals referred to the strange black aircraft as “Habus” because of its general resemblance to the reptile, and the name stuck. For both the SR-71s and the crews, they referred to themselves as Habus, and the reconnaissance missions conducted off the OL-8 base were referred to as Habu missions.
The Soviets already knew well of the unusual aircraft being launched from Kadena, as they had one of their “fishing trawlers” standing radar picket duty every time one of the CIA A-12s had taken off. A string of Soviet spy ships continued the procedures along the China coast, tracking the high-flying aircraft on their way to Vietnam. Coordinated tracking of the flights was conducted with Chinese surveillance radars and the information sent on to North Vietnamese military officials, and SA-2 target acquisition radars would lock on to the approaching SR-71s.
The long black craft could cross the entire country of Vietnam in eight minutes, and the SA-2 crews were able to do little about it in spite of the early warnings from their Communist allies.
In June 1970, a special mission planning board was created to look at the possibility of conducting a rescue operation for POWs held in North Vietnam. The target of the mission was going to be the Son Tay camp, located twenty-three miles to the west of Hanoi. The SR-71 crews knew the Son Tay area well, since they had been conducting recon flights over the area since 1968. Their mission was to try and determine the number of POWs held at the camp at any given time. Few other assets were available to maintain the level of quality surveillance over the Son Tay camp necessary for the rescue mission without attracting the attention of the North Vietnamese.
While U.S. Special Forces volunteers trained diligently to rescue American POWs, the SR-71 overflights continued. Enough intelligence was gathered to suggest that a rescue could result in the freeing of as many as sixty-three U.S. servicemen held at the Son Tay site. Using some of the information gathered by the SR-71s from Kadena, a mock prison camp was set up at Hurlburt Air Force Base in Florida. The camp layout was exact and the Special Forces men rehearsed all phases of the mission, code-named Operation Kingpin. Specific parameters were required for the operation, including clear weather and a quarter-moon a given distance (35 degrees) above the horizon for maximum visibility of the area for the nighttime operation. The windows for the operation that met the mission parameters were October 21-25 and November 21-25. The decision was made and the mission a go for November 21, 1970.
In the last weeks leading up to the execution of Operation Kingpin cloud cover prevented a view of the Son Tay area from the SR-71 flights. Low-flying drones were tried twice to gather the last-minute intelligence but they were never recovered. The mission went forward without the intelligence being available regarding the last few weeks around the camp.
President Nixon gave the final approval for Operation Kingpin on November 18. A coordinated strike against North Vietnam was conducted by Navy aircraft coming in as the Kingpin transport helicopters were moving into the Hanoi area. Because of a suspension of active bombing missions against North Vietnam at the time, many of the Navy aircraft were not carrying any offensive ordnance, but they did distract the North Vietnamese.
At 2:18 A.M. on the morning of November 21, an HH3 Jolly Green Giant transport helicopter crashed-landed according to plan in the center of the Son Tay prison compound. The operation went flawlessly with a short, vicious firefight taking out one hundred to two hundred of the North Vietnamese Army soldiers who tried to repel the invaders.
In spite of the success of the raid against the NVA troops, there was a major problem with the mission as a whole. There were no prisoners at Son Tay to be rescued by the Special Forces troopers who had come so far and risked so much. In spite of an intensive search, no POWs were found. There were no losses among the Special Forces troops and only one man was wounded during the engagement. They successfully extracted after slightly less than thirty minutes on the ground.
It was learned later that the sixty-five POWs who had been at Son Tay had been moved in July because of the threat of flooding in the area. The mission was declared a tactical success but an intelligence failure. It was only the day before the raid that intelligence estimates had suspected that the POWs had been moved to another prison site about fifteen miles away from Son Tay. That estimation was later proved to be the correct one. Since all of the planning for Kingpin had centered on Son Tay, command decided to continue with the mission as originally laid out since moving the objective at the last minute would have put all of the raiders and supporting assets at too great a risk.
Only a short time following the raid at Son Tay, SR-71 overflights brought back photographic evidence of the damage done by the Special Forces troopers. These pictures became famous back in the United States, though it would be years before the public knew the full story of Operation Kingpin, and even longer before the involvement of the Habus from Okinawa became known. But the Son Tay raid would not be the only time that the SR-71 aircraft and crews would be involved in trying to rescue their fellow servicemen in North Vietnam.
The relatively few SR-71s available and their operating expense of $30,000 an hour during flight time made their mission tasking one that took serious consideration. Major intelligence and command organizations, such as the Defense Intelligence Agency, National Security Agency, and the Commander in Chief Southeast Asia, all had to have their tasking assignments for the SR-71 prioritized and approved, sometimes by very high offices. Missions could not be done just “off-the-cuff,” as extensive preparations to the aircraft and its navigational systems were needed beforehand.
Approval for missions could come from very high sources depending on just where the SR-71s were intended to fly. Violating the sovereign airspace of foreign countries was not something to be taken lightly. Mission approval would have to come down from the State Department, a select secret committee of the National Security Council, or the president of the United States, depending on the operations parameters. Once that approval had been received, the SAC Reconnaissance Center would send the tasking on through the command chain, setting events in motion that resulted in the Habus moving into the air.
SR-71 missions had expanded from one a week during their early years at OL-8. During the later years of the Vietnam War, missions were being flown on an almost daily basis. But some operations stood out from the others, not just for where the great black aircraft were going, but for what they were going to doâand why.