Lockheed U-2

The Lockheed U-2, nicknamed "Dragon Lady", is a single-engine, high altitude reconnaissance aircraft operated by the United States Air Force (USAF) and previously flown by the Central Intelligence Agency (CIA). It provides day and night, very high-altitude (70,000 feet / 21,000 m), all-weather intelligence gathering. The U-2 has also been used for electronic sensor research, satellite calibration, and communications purposes.

The U-2 has been prominently featured in several events during the Cold War, at stages of which U-2s commonly overflew the Soviet Union, the People's Republic of China, North Vietnam, and Cuba. In 1960, CIA pilot Gary Powers was shot down while flying a U-2 over Soviet territory. In 1962, a U-2 piloted by Major Rudolf Anderson, Jr. was shot down over Cuba by surface-to-air missiles during the Cuban missile crisis.

The U-2 has remained in service since the end of the Cold War and is one of several aircraft types that have been operated by the USAF in excess of 50 years. It has participated in conflicts such as Afghanistan and Iraq, and supported several multinational NATO operations. The role of the U-2 is increasingly performed by alternative platforms, such as surveillance satellites, unmanned reconnaissance drones such as the Northrop Grumman RQ-4 Global Hawk, and conventional aircraft.

Background
After World War II the U.S. military desired better strategic reconnaissance to help determine Soviet capabilities and intentions. Into the 1950s the best intelligence the American government had on the interior of the Soviet Union was German Luftwaffe photographs taken during the war of territory west of the Ural Mountains, so overflights to take aerial photographs of the Soviet Union began. After 1950 Soviet air defenses aggressively attacked all aircraft near its borders—sometimes even those over Japanese airspace—and the existing reconnaissance aircraft, primarily bombers converted for reconnaissance duty such as the RB-47, were vulnerable to anti-aircraft artillery, missiles, and fighters. Richard Leghorn of the United States Air Force suggested that an aircraft that could fly at 60,000 feet should be safe from the MiG-17, the Soviet Union's best interceptor, which could barely reach 45,000 feet. He and others believed that Soviet radar, which used American equipment provided during the war, could not track aircraft above 65,000 feet.

The highest-flying aircraft available to America and its allies at the time was the English Electric Canberra, which could reach 48,000 feet. The British had already produced the PR3 photo-reconnaissance variant, but the USAF asked English Electric's help to help further modify the Martin B-57—the American licensed version of the Canberra—with long, thin wings, new engines, and a lighter-than-normal airframe to reach 67,000 feet during flight. Air Research and Development Command mandated changes to the design which, although they made the aircraft more durable during wartime, meant that the resulting RB-57D aircraft of 1955 could only reach 64,000 feet. The Soviet Union, unlike the United States or Britain, had also improved radar technology after the war, and could track aircraft above 65,000 feet.

Lockheed proposal
It was thought an aircraft that could fly at 70,000 feet (21,000 m) would be beyond the reach of Soviet fighters, missiles, and radar. Another U.S. Air Force officer, John Seaberg, wrote in 1953 a request for proposal for an aircraft that could reach 70,000 feet over a target with 1,500 nautical miles of operational radius. The USAF decided to only solicit designs from smaller aircraft companies that could give the project more attention. Under the code name "Bald Eagle", it gave contracts to Bell Aircraft, Martin Aircraft, and Fairchild Engine and Airplane to develop proposals for the new reconnaissance aircraft. Officials at Lockheed Aircraft Corporation heard about the project and decided to submit an unsolicited proposal. To save weight and increase altitude, Lockheed executive John H. Carter suggested that the design eliminate landing gear and avoid attempting to meet combat load factors for the airframe. The company asked Clarence "Kelly" Johnson to come up with such a design. Johnson was Lockheed's best aeronautical engineer, responsible for the P-38, and the P-80. He was also known for completing projects ahead of schedule, working in a separate division of the company jokingly called the Skunk Works.



Johnson's design, called the CL-282, attached long glider-like wings to the fuselage and General Electric J73 engine of another of his planes, the Lockheed F-104 Starfighter. The aircraft, essentially a jet-powered glider, took off from a dolly and landed on skids, and could reach 70,000 feet in altitude with a 2,000-mile range. In June 1954 the USAF rejected the design in favor of the Bell X-16 and the modified B-57. Reasons included the lack of landing gear, usage of the J73 engine instead of the more proven Pratt & Whitney J57 like the competing designs, and not using multiple engines which, the USAF believed, was more reliable. (General Curtis LeMay of Strategic Air Command (SAC) walked out during a CL-282 presentation, saying that he was not interested in an airplane without wheels or guns.)

Approval
Civilian officials such as Trevor Gardner, an aide to Secretary of the Air Force Harold E. Talbott, were more positive on the CL-282 because of its higher potential altitude and smaller radar cross section, and recommended the design to the Central Intelligence Agency (CIA)'s Office of Scientific Intelligence. At this time the CIA depended on the military for overflights, and Director of Central Intelligence (DCI) Allen Dulles favored human over technical intelligence gathering methods. However, the Intelligence Systems Panel, a civilian group advising the USAF and CIA on aerial reconnaissance, by 1954 recognized that the RB-57D would not meet the 70,000-feet requirement that panel member Allen Donovan of Cornell Aeronautical Laboratory believed was necessary for safety. The CIA told the panel about the CL-282, and the aspects of its design that the USAF saw as flaws—the single engine and light load factor—appealed to Donovan, a sailplane enthusiast who believed that a sailplane was the type of high-altitude aircraft the panel was seeking.

Edwin Land, the father of instant photography and another member of the panel, proposed to Dulles through Dulles' aide Richard M. Bissell, Jr. that his agency should fund and operate this aircraft. Land believed that the military operating the CL-282 during peacetime could provoke a war. Although Dulles remained reluctant to have the CIA conduct its own overflights, Land and James Killian of MIT told President Eisenhower about the aircraft; Eisenhower agreed that the CIA should be the operator. Dulles finally agreed, but some U.S. Air Force officials opposed the project because they feared it would endanger the RB-57D and X-16. The USAF's Seaberg helped persuade his own agency to support the CL-282, albeit with the higher-performance J57 engine, and final approval for a joint USAF-CIA project—the first time the CIA dealt with sophisticated technology—came in November 1954. Lockheed had meanwhile become busy with other projects and had to be persuaded to accept the CL-282 contract after approval.

Manufacture
Bissell became head of the project, which used covert funding. (Under the Central Intelligence Agency Act of 1949, the DCI is the only federal government employee who can spend "un-vouchered" government money.) Lockheed received a $22.5 million contract in March 1955 for the first 20 aircraft, with the first $1.26 million mailed to Johnson's home in February 1955 to keep work going during negotiations. The company agreed to deliver the first aircraft by July of that year and the last by November 1956. It did so, and for $3.5 million under budget, because the aircraft was based on the F-104; only the wings and tail were different.

Procurement of the aircraft's components occurred secretly. When Johnson ordered altimeters calibrated to 80,000 feet from a company whose instruments only went to 45,000 feet, the CIA set up a cover story involving experimental rocket aircraft. Shell Oil developed a new low-volatility, low vapor pressure jet fuel that would not evaporate at high altitudes; the fuel became known as JP-7, and manufacturing several hundred thousand gallons for the aircraft in 1955 caused a nationwide shortage of Shell's Flit insect repellant. The aircraft was renamed the U-2 in July 1955, the same month the first aircraft, Article 341, was delivered to Groom Lake. The "U" referred to the deliberately vague designation "utility" instead of "R" for "reconnaissance", and the U-1 and U-3 aircraft already existed. The CIA assigned the cryptonym "Aquatone" to the project, with the USAF using the name "Oilstone" for their support to the CIA.

James Baker developed the optics for a large-format camera to be used in the U-2 while working for Perkin-Elmer. These new cameras had a resolution of 2.5 ft from an altitude of 60000 ft. The aircraft was so crowded that when Baker asked Johnson for six more inches of space for a lens of 240-inch focal length, Johnson replied "I'd sell my grandmother for six more inches!"; Baker instead used a 180-inch f/13.85 lens in a 13" by 13" format for his final design. Balancing is so critical on the U-2 that the camera had to use a split film, with reels on one side feeding forward while those on the other side fed backward, thus maintaining a balanced weight distribution through the whole flight.

When the first overflights of the Soviet Union were tracked by radar, the CIA initiated Project Rainbow to reduce the U-2's radar cross section. This effort ultimately proved unsuccessful, and work began on a follow-on aircraft, which resulted in the Lockheed A-12 Oxcart. Manufacturing was restarted in the 1980s to produce the TR-1, an updated and modernized design of the U-2.

Design


The unique design that gives the U-2 its remarkable performance also makes it a difficult aircraft to fly. It was designed and manufactured for minimum airframe weight, which results in an aircraft with little margin for error. Most aircraft were single-seat versions, with only five two-seat trainer versions known to exist. Early U-2 variants were powered by Pratt & Whitney J57 turbojet engines. The U-2C and TR-1A variants used the more powerful Pratt & Whitney J75 turbojet. The U-2S and TU-2S variants incorporated the even more powerful General Electric F118 turbofan engine.

High aspect ratio wings give the U-2 some glider-like characteristics, with an engine out glide ratio of about 23:1, comparable to gliders of the time. To maintain their operational ceiling of 70000 ft, the U-2A and U-2C models (no longer in service) had to fly very near their Never exceed speed (VNE). The margin between that speed and its stall speed at that altitude is only 10 kn below its maximum speed. This narrow window was referred to by the pilots as the "coffin corner", because breaching either limit would likely cause the wings or tail to fall off the delicate plane. For 90% of the time on a typical mission the U-2 was flying within only five knots above stall, which might cause a decrease in altitude likely to lead to detection, and additionally might overstress the lightly built airframe.



The U-2's flight controls are designed around the normal flight envelope and altitude at which the aircraft was intended to fly. The controls provide feather light control response at operational altitude. However, at lower altitudes, the higher air density and lack of a power assisted control system makes the aircraft very difficult to fly. Control inputs must be extreme to achieve the desired response in flight attitude, and a great deal of physical strength is needed to operate the controls in this manner.

The U-2 is very sensitive to crosswinds which, together with its tendency to float over the runway, makes the aircraft notoriously difficult to land. As it approaches the runway, the cushion of air provided by the high-lift wings in ground effect is so pronounced that the U-2 will not land unless the wing is fully stalled. A landing U-2 is accompanied on the ground by a chase car and an assisting U-2 pilot calling off the angles and declining aircraft height as the aircraft descends. Cars used have been Ford Mustang SSP, Chevrolet Camaro B4C, Pontiac GTO, Dodge Charger Police Package, Pontiac G8 GT, and Chevrolet Camaro SS.

Instead of the typical tricycle landing gear, the U-2 uses a bicycle configuration with a forward set of main wheels located just behind the cockpit, and a rear set of main wheels located behind the engine. The rear wheels are coupled to the rudder to provide steering during taxiing. To maintain balance while taxiing, two auxiliary wheels, called "pogos" are added for takeoff. These fit into sockets underneath each wing at about mid-span, and fall off during takeoff. To protect the wings during landing, each wingtip has a titanium skid. After the U-2 comes to a halt, the ground crew re-installs the pogos one wing at a time, then the aircraft taxis to parking.

Because of the high operating altitude and the cockpit's partial pressurization, equivalent to 28,000 feet, the pilot wears a partially pressurized space suit, which delivers the pilot's oxygen supply and provides emergency protection in case cabin pressure is lost. While pilots can drink water and eat food in squeezable containers through a self-sealing hole in the face mask, they typically lose up to six pounds of weight on an eight-hour mission. Most pilots chose to not take with them the suicide pill offered before missions. If put in the mouth and bitten, the "L-pill"—containing liquid potassium cyanide—would cause death in 10 to 15 seconds. After a pilot almost accidentally ingested an L-pill instead of candy during a December 1956 flight the suicide pills were put into boxes to avoid confusion. When in 1960 the CIA realized that a pill breaking inside the cockpit would kill the pilot, it destroyed the L-pills and its Technical Services Division developed a needle poisoned with a powerful shellfish toxin and hidden in a silver dollar. Only one was made because, as the agency decided, if any pilot needed to use it the program would probably be canceled.

To prevent hypoxia and decrease the chance of decompression sickness, pilots begin breathing 100% oxygen an hour prior to take off to remove nitrogen from the body; a portable oxygen supply is used prior to entering the aircraft. Since 2001, more than a dozen pilots have been reported to have suffered the effects of decompression sickness, including permanent brain damage in nine. Initial symptoms include becoming suddenly unable to read, and disorientation. Factors increasing the risk of illness since 2001 included longer mission durations and more cockpit activity. Conventional reconnaissance missions would limit pilot duties to maintaining flight path for camera photography; operations over Afghanistan included more real time activities, such as communication with ground troops, increasing their bodies' oxygen requirements and the risk of nitrogen bubble formation. The USAF is studying the issue; U-2 pilots now exercise during oxygen pre-breathing. Among other remedies proposed is an increased cockpit pressurization to a 15,000 feet equivalent. In 2013, modifications were initiated under the Cockpit Altitude Reduction Effort (CARE), to beef up the cockpit structure. This will allow the cockpit cabin pressure to be increased from 3.88 psi to 7.65 psi, lowering the cockpit pressurization to a 15,000 feet equivalent. In addition, the urine collection device was rebuilt as part of CARE to eliminate corrosion caused by leakage.



The aircraft carries a variety of sensors in the nose, Q-bay (behind the cockpit, also known as the camera bay), and wing pods. The U-2 is capable of simultaneously collecting signals, imagery intelligence and air samples. Imagery intelligence sensors include either wet film photo, electro-optic or radar imagery – the latter from the Raytheon ASARS-2 system. It can use both line-of-sight and beyond-line-of-sight data links. One of the most unusual instruments in the newest version of the U-2 is the off-the-shelf Sony video camera that functions as a digital replacement for the purely optical viewsight (an upside down periscope-like viewing device) that was used in older variants to get a precise view of the terrain directly below the aircraft, especially during landing.

Pilot selection and training
Though the U.S. Air Force and Navy would eventually fly the U-2 the CIA had majority control over the project, code named Project Dragon Lady. Despite SAC chief LeMay's early dismissal of the CL-282, the USAF in 1955 sought to take over the project and put it under SAC until Eisenhower reiterated his opposition to military personnel flying the aircraft. Nonetheless, the U.S. Air Force substantially participated in the project; Bissell described it as a "49 percent" partner. The USAF agreed to select and train pilots and plot missions, while the CIA would handle cameras and project security, process film, and arrange foreign bases.

Beyond not using American military personnel to fly the U-2, Eisenhower preferred to use non-US citizens. the nationalities of the foreign pilots the CIA recruited remain classified. They did not have the appropriate flying experience for the U-2, however, and the language barrier was a problem; by fall 1955 the foreign pilots were out of the program. The program instead turned to Americans. Pilots had to resign their military commissions before joining the agency as civilians, a process they referred to as "sheep dipping", and were always called "drivers", not pilots. The program only recruited from SAC fighter pilots with reserve USAF commissions, as regular commissions complicated the resignation process. To persuade pilots to resign, the program offered high salaries and the USAF's promise that they could return to their units at the same ranks as other officers. The CIA's standards for selection were higher than those of the USAF's once the latter began its own U-2 flights; although more candidates were rejected, those who passed the CIA's program had a much lower accident rate. Test pilot Tony LeVier trained other Lockheed pilots to fly the U-2, who by September 1955 trained six USAF pilots who, in turn, trained the "sheep-dipped" pilots. As no two-seat trainer model was available for the first 15 years of the program, all training had to be done before the trainee's first solo flight and via radio. The experienced fighter pilots had to adjust to the U-2's unusual combination of jet and enormous, high-lift glider wings, and because of the "coffin corner" learned that they had to pay complete attention to flying when not using the autopilot.

Test flights
As with CIA involvement, besides the normal serial number for each aircraft produced, each U-2 also has an "article number" assigned, and each U-2 would be referred to with its article number on classified internal documents/memos. The prototype U-2, Article 341, never received an USAF serial. The first flight occurred at Groom Lake on 1 August 1955, during what was intended to be only a high-speed taxi test run of Article 341. The sailplane-like wings were so efficient that the aircraft jumped into the air at 70 kn, amazing LeVier who, as he later said, "had no intentions whatsoever of flying". The lake bed had no markings making it difficult for LeVier to judge the distance to the ground, and the brakes proved too weak; he bounced the U-2 once before it stopped rolling. Although the aircraft suffered only minor damage, LeVier again found landing the U-2 difficult during the actual first test flight three days later. On his sixth try, he found that landing the aircraft touch down on the rear wheel first was superior to the front. (Future pilots new to the U-2 would also have difficulty during landing because at low speeds ground effect would keep the aircraft above the ground for long distances.) On 8 August, the first flight occurred in front of Bissell and other outside observers. The U-2 reached 32,000 feet, proving that Johnson had met his promised specifications and deadline. By 16 August, the prototype flew at 52,000 feet, an altitude never before reached in sustained flight; by 8 September, it reached 65,000 feet.

By January 1956 the U-2 so impressed SAC that it wished to purchase its own aircraft. The U.S. Air Force would purchase a total of 31 U-2s through the CIA; the transaction's code name, Project Dragon Lady, was the origin of the aircraft's nickname. Meanwhile, U-2s conducted eight overflights of the United States during April 1956 that convinced the project that the aircraft was ready for deployment. As often happens with new aircraft designs, there were several operational accidents. One occurred during these test flights, when a U-2 suffered a flameout over Tennessee; the pilot calculated that he could reach New Mexico. Every air base in the continental United States had sealed orders on what to do if a U-2 landed. The commander of Kirtland Air Force Base near Albuquerque was told to open his orders, prepare for the landing of an unusual aircraft making a deadstick landing, and get it inside a hangar as soon as possible. The U-2 successfully landed after having glided more than 300 miles, and its strange, glider-like appearance and the space-suited pilot startled the base commander and other witnesses.

Not all U-2 incidents would be so benign, with three fatal accidents occurring in 1956 alone. The first fatal accident was on 15 May 1956, when the pilot stalled the aircraft during a post-takeoff maneuver that was intended to drop off the wingtip outrigger wheels. The second occurred three months later, on 31 August when the pilot stalled the aircraft immediately after takeoff. On 17 September a third aircraft disintegrated during ascent in Germany, also killing the pilot. There were other non-fatal incidents, including at least one that resulted in the loss of the aircraft.

Cover story
A committee of Army, Navy, Air Force, CIA, NSA, and State Department representatives created lists of priority targets for U-2 and other intelligence gathering methods. The U-2 project received the list and drew up flight plans, and the committee provided a detailed rationale for each plan for the president to consider as he decided whether to approve it. The CIA's Photo Intelligence Division grew in size to prepare for the expected flood of U-2 photographs. Before the aircraft became operational, however, the Air Force's Project Genetrix, which used high altitude balloons to photograph the Soviet Union, China, and Eastern Europe, led to many diplomatic protests from those countries and for a while CIA officials feared that the U-2 project was at risk. While Genetrix was also a technical failure—only 34 of the 516 balloons returned usable photographs—the balloon flights gave the United States many clues on how the Communist countries used radar to handle overflights, which benefited the U-2 program.

With approval from the National Advisory Committee on Aeronautics (NACA)'s director Hugh Dryden, Bissell's team at the CIA developed a cover story for the U-2 which described the aircraft as used by NACA for high altitude weather research; the cover story would be used if the aircraft were lost over hostile territory. To support the story, U-2s several times took weather photographs that appeared in the press. The civilian advisers Land and Killian disagreed with the cover story, advising that if an aircraft was lost that the United States forthrightly acknowledge its use of U-2 overflights "to guard against surprise attack". Their advice was not followed, and the weather cover story led to the disaster that followed the May 1960 U-2 loss.

First overflights of Communist territory
The British government in January 1956 approved the U-2's deployment from RAF Lakenheath. NACA announced that the USAF Air Weather Service would use a Lockheed-developed aircraft to study the weather and cosmic rays at altitudes up to 55,000 feet; accordingly, the first CIA detachment of U-2s ("Detachment A") was known publicly as the 1st Weather Reconnaissance Squadron, Provisional (WSRP-1). The death, however, in April 1956 of British agent Lionel Crabb while examining Soviet ships in Portsmouth harbor, embarrassed the British government, which asked the United States to postpone the Lakenheath flights. To avoid delays, in June 1956, Detachment A moved to Wiesbaden, Germany without approval from the German government, while Giebelstadt Army Airfield was prepared as a more permanent base.

Eisenhower remained worried that despite their great intelligence value, overflights of the Soviet Union might cause a war. While the U-2 was under development, at the 1955 Geneva Summit he proposed to Nikita Khruschev that the Soviet Union and the United States would each grant the other country airfields to use to photograph military installations. Khruschev rejected the "Open Skies" proposal, and the CIA told the president that the Soviets could not track high altitude U-2 flights. This belief was based on studies using old Soviet radar systems and American systems which, unknown to the US, were not as effective at high altitudes as current Soviet systems. Although the Office of Scientific Intelligence issued a more cautious report in May 1956 that stated that detection was possible, it believed that the Soviets could not consistently track the aircraft. DCI Dulles further told Eisenhower, according to presidential aide Andrew Goodpaster, that in any aircraft loss the pilot would almost certainly not survive. With such assurances and the growing demand for accurate intelligence regarding the alleged "bomber gap" between the United States and the Soviet Union, Eisenhower approved in June 1956 10 days of overflights.

The first U-2 overflight had already occurred, using existing authorization of Air Force overflights over Eastern Europe. On 20 June 1956 a U-2 flew over Poland and East Germany, with more flights on 2 July. The fact that radar had—contrary to the CIA's expectations—successfully tracked the aircraft worried Eisenhower, but he approved the first Soviet overflight, Mission 2013 on 4 July. U-2 Article 347's main target was the Soviet submarine construction program in Leningrad, as well as counting the numbers of the new Myasishchev M-4 "Bison" bomber. A second flight on 5 July continued searching for Bisons, photographed Moscow (the only ones taken by the program), and examined rocket factories at Kaliningrad and Khimki. Eisenhower knew from the earlier overflights that his hope of no Soviet detection was unrealistic, but ordered that the overflights stop if the aircraft could be tracked. The CIA found that the Soviets could not consistently track the U-2s, and they therefore did not know that Moscow and Leningrad had been overflown. The aircraft's photographs showed tiny images of MiG-15s and MiG-17s attempting and failing to intercept the aircraft, proving that the Soviets could not shoot down an operational U-2.

U-2 missions from Wiesbaden would depart westward in order to gain altitude over friendly territory before turning eastwards at operational altitudes. The NATO Air Defence mission in that area included No. 1 Air Division RCAF (Europe), which operated the Canadair Sabre Mark 6 from bases centred on the northeastern corner of France. This aircraft had a service ceiling of 54,000 feet and numerous encounters between the U-2 and RCAF 'ZULU' alert flights have been recorded for posterity.

"Bomber gap" disproven
The Soviets on 10 July protested what they described as overflights by a USAF "twin-engine medium bomber", apparently believing that it was a Canberra. The United States replied on 19 July that no American "military planes" had overflown the Soviet Union, but the fact that the Soviets' report showed that they could track the U-2s for extended periods caused Eisenhower to immediately halt overflights over Eastern Europe. Beyond the Soviet protests, the president was concerned about American public reaction to news that the United States had violated international law. To avoid project cancellation, the CIA began Project RAINBOW to make the U-2 less detectable. The eight overflights over Communist territory, however, had already shown that the bomber gap did not exist; the U-2s had not found any Bison bombers at the nine bases they had visited. Because the Eisenhower administration could not disclose the source of its intelligence, however, Congressional and public debate over the bomber gap continued.

Suez Crisis
The presidential order did not restrict U-2 flights outside Eastern Europe. In May 1956 Turkey approved the deployment of Detachment B at Incirlik Air Base, near Adana. Before the new detachment was ready, however, Detachment A in late August used Adana as a refueling base to photograph the Mediterranean. The aircraft found evidence of many British troops on Malta and Cyprus as the United Kingdom prepared for its forthcoming intervention in Suez. The United States released some of the photographs to the British government. As the crisis grew in seriousness, the project converted from a source of strategic reconnaissance, which prioritized high quality over speed (the film was processed by its maker, then analyzed in Washington), to a tactical reconnaissance unit that provided immediate analysis. The Photo Intelligence Division set up a lab at Wiesbaden; as Detachment B took over from A and flew over targets that remain classified, the Wiesbaden lab's rapid reports helped the United States government to predict the Israeli-British-French attack on Egypt three days before it began on 29 October. On 1 November a flight flew over the Egyptian air base at Almaza twice, 10 minutes apart; in between the British and French attacked the base, and the visible results of the attack in the "ten-minute reconnaissance" impressed Eisenhower. Beginning on 5 November, flights over Syria showed that the Soviets had not sent aircraft there despite their threats against the British, French and Israelis, a cause of worry for the United States.

Renewal of Eastern Bloc overflights
Eisenhower refused CIA pleas in September 1956 to reauthorize overflights of Eastern Europe but the Hungarian Revolution in November, and his reelection that month, caused the president to permit flights over border areas. Soviet interceptors continued to fail to reach the U-2s but, after the Soviets protested a December overflight of Vladivostok by RB-57Ds, Eisenhower again forbade Communist overflights. Flights close to the border continued, now including the first ELINT-equipped U-2s. In May 1957 the president again authorized overflights over certain important Soviet missile and atomic facilities. He continued to personally authorize each flight, closely examining maps and sometimes making changes to the flight plan. By 1957, one of the European units was based at Giebelstadt, and the Far Eastern unit was based at the Naval Air Facility Atsugi, Japan.

Part of the reason for the May reauthorization was that the CIA promised that improvements from Project RAINBOW would make the majority of U-2 flights undetected. On 2 April 1957 a RAINBOW test flight crashed in Nevada, killing the pilot. The U-2's large wingspan slowed its descent during crashes, often leaving its remains salvageable; Lockheed was able to rebuild the wreckage from the incident into a flyable airframe, but that it could do so should have been evidence to the CIA that its cover story might not be viable after a crash in hostile territory. The RAINBOW anti-radar modifications were not very successful, and their use ended in 1958.

Soviet overflights resumed in June 1957 from Eielson Air Force Base in Alaska to the Russian Far East, which had less effective radar systems. Others originated from Lahore, Pakistan. A Lahore flight on 5 August provided the first photographs of the Baikonur Cosmodrome near Tyuratam, the existence of which the CIA was unaware. Other flights examined the Semipalatinsk nuclear test site and the Saryshagan missile test site. After a few more overflights that year, only five more would occur before the May 1960 incident because of Eisenhower's increasing cautiousness. The president sought to avoid angering the Soviets as he worked to achieve a nuclear test ban; meanwhile the Soviets began trying to shoot down even U-2 flights that never entered Soviet airspace, and the details in their diplomatic protests showed that Soviet radar operators were able to effectively track the aircraft. The Soviets developed their own overflight aircraft, variants of the Yak-25, which in addition to photographing various parts of the world through the early 1960s acted as a target for the new MiG-19 and MiG-21 interceptors to practice for the U-2. Lockheed painted the aircraft in a blue-black color that helped them blend in against the darkness of space, and the CIA aircraft received the more powerful J75-P13 engine that increased maximum altitude by 2,500 feet, to 74,600.

The "missile gap"
The successful launch of Sputnik 1 in October 1957 gave credence to Soviet claims about the progress of its ICBM program. In December 1958 Khruschev boasted that a Soviet missile could deliver a 5-megaton warhead 8,000 miles. Although the Soviets' SS-6 Sapwood missile program was actually stalled due to technical failures, subsequent boasts—and United States Secretary of Defense Neil McElroy's statement in February 1959 to Congress that the Soviets might have a three-to-one temporary advantage in ICBMs during the early 1960s—caused widespread concern in the United States about the existence of a "missile gap". The American intelligence community was divided, with the CIA suspecting technical delays but the Air Force believing that the SS-6 was ready for deployment. Khruschev continued to exaggerate the Soviet program's success; the missile gap concerns, and CIA and State Department support, caused Eisenhower to reauthorize one Communist territory overflight in July 1959 after 16 months, as well as many ELINT flights along the Soviet border. One British U-2 overflight meanwhile occurred in December, and another in February 1960, but neither proved nor disproved the missile gap. The British flights' success contributed to Eisenhower's authorization of one overflight in April.

Khruschev claimed in his memoir that the April flight should have been shot down by new Soviet surface-to-air missiles (SAMs), but the missile crews were slow to react. By this time the CIA had concluded internally that Soviet SAMs had "a high probability of successful intercept at 70,000 feet providing that detection is made in sufficient time to alert the site", and the April flight was tracked quickly. Despite the now much greater risk, the CIA failed to stop the overflights because of overconfidence from the years of successful missions, and because of the strong demand for more missile site photos. By this time the U-2 was the major source of covert intelligence on the Soviet Union; the aircraft had photographed about 15% of the country, resulting in almost 5,500 separate intelligence reports. Eisenhower authorized one more overflight to occur no later than 1 May, because the important Paris Summit would begin on 16 May.

May 1960 U-2 incident


The CIA chose for the mission—the 24th deep-penetration Soviet overflight—Operation GRAND SLAM, an ambitious flight plan for the first crossing of the Soviet Union from Peshawar, Pakistan to Bodo, Norway; previous flights had always exited in the direction they had entered. The route would permit visits to Tyuratam, Sverdlovsk, Kirov, Kotlas, Severodvinsk, and Murmansk. Francis Gary Powers, the most experienced pilot with 27 missions, was chosen to fly the U-2. After delays the flight began on May Day, 1 May; this was a mistake because as an important Soviet holiday there was much less air traffic than usual. The Soviets began tracking the U-2 15 miles outside the border, and over Sverdlovsk, four and one half hours into the flight, one of three SA-2 missiles detonated behind the aircraft at 70,500 feet; another hit a Soviet interceptor attempting to reach the American aircraft. Powers survived the near miss and was quickly captured; the crash did not destroy the U-2 and the Soviets were able to identify much of the equipment.

Bissell and other project officials believed that surviving a U-2 accident from above 70,000 feet was impossible, so used the preexisting cover story. On 3 May the National Aeronautics and Space Administration (NASA, the successor to NACA) announced that one of its aircraft, making a high altitude research flight in Turkey, was missing; the government planned to, if necessary, say that the NASA aircraft had drifted with an incapacitated pilot across the Soviet border. By remaining silent, Khruschev lured the Americans into reinforcing the cover story until he revealed on 7 May that Powers was alive and had confessed to spying on the Soviet Union. Eisenhower turned down DCI Dulles' offer to resign and publicly took full responsibility for the incident on 11 May; by then all overflights were canceled. The Paris Summit collapsed after Khruschev, as the first speaker, demanded an apology from the United States which Eisenhower refused.

Powers had little instruction on what to do during an interrogation. Although he had been told that he could reveal everything since the Soviets could learn what they wanted from the aircraft, Powers did his best to conceal classified information while appearing to cooperate. His trial began on 17 August 1960. Powers—who apologized on advice of his Soviet defense counsel—was sentenced to three years in prison, but on 10 February 1962 the USSR exchanged him and American student Frederic Pryor for Rudolf Abel at Glienicke Bridge between East and West Berlin. Two CIA investigations found that Powers had done well during the interrogation, "compl[ying] with his obligations as an American citizen during this period". Although the government was reluctant to reinstate him to the USAF because of its statements that the U-2 program was civilian, it had promised to do so after CIA employment ended. Powers resolved the dilemma by choosing to work for Lockheed as a U-2 pilot.

Changes to CIA program
Immediately after the Soviets announced that Powers was alive, the CIA evacuated the British pilots from Detachment B as Turkey did not know of their presence in the country. The end of Soviet overflights meant that Detachment B itself soon left Turkey, and in July Detachment C left Japan after a Japanese governmental request. Both detachments merged into Detachment G at Edwards Air Force Base, California, where the CIA had relocated the U-2 program after nuclear testing forced it to move from Groom Lake in 1957. By the next U-2 flight, in October 1960 over Cuba, the previously informal procedure in which the president personally approved or disapproved each flight after discussion with advisors was replaced by the National Security Council Special Group. The expansion of satellite intelligence partly compensated for the overflights' end, but because U-2 photographs remained superior to satellite imagery future administrations considered resumption at times, such as during the Berlin Crisis of 1961.

Cuba
From October 1960 Detachment G made many overflights of Cuba from Laughlin Air Force Base, Texas. Although Lockheed in 1961 modified six CIA aircraft into the aerial refueling-capable U-2F model, permitting some Cuba missions to originate from Edwards, flights could not last for more than about 10 hours because of pilot fatigue. A late August 1962 flight showed Soviet SA-2 SAM sites on the island; later overflights found more sites and the MiG-21 interceptor. The increasing number of SAMs caused the United States to become more cautious when planning Cuban CIA overflights. The Air Force's U-2s did not conduct overflights, but officials believed that it would be better for a military officer to be the pilot in case he was shot down. After receiving hasty training on the CIA's more-powerful U-2C aircraft, SAC Major Richard S. Heyser flew an overflight of western Cuba on 14 October; his was the first to photograph Soviet MRBMs in San Cristobal. SAC received permission to fly as many Cuban overflights as necessary for the duration of the resulting Cuban Missile Crisis. On 27 October a SA-2 missile killed SAC Major Rudolf Anderson flying a CIA U-2C; he posthumously received the first Air Force Cross. Fulfilling CIA officials' fears of a USAF takeover, CIA pilots never again flew over Cuba; SAC retained control over Cuban overflights, which continued until the 1970s under the code name OLYMPIC FIRE. At the same time as the Crisis, Royal Air Force English Electric Lightnings of the Air Fighting Development Squadron made several practice interceptions against U-2s on Soviet overflight operations from the UK. Under ground-controlled interception and using energy climb profiles they could intercept the U-2 at up to 65,000 ft.

Asia
CIA overflights of Asian targets began in spring 1958, when Detachment C moved from Japan to Cubi Point Naval Air Station in the Philippines to overflight Indonesia during an uprising against Sukarno's "Guided Democracy" government. The CIA's Civil Air Transport, aiding the rebels, so badly needed pilots that it borrowed two CIA U-2 pilots despite the high risk to the U-2 program if one were captured. The Indonesian government soon defeated the rebels, however, and the U-2s returned to Japan. That year, Detachment C also flew over the Chinese coast near Quemoy during the Second Taiwan Strait Crisis to see if Chinese forces were preparing to invade, and in 1959 aided CIA operations during the Tibetan uprising. The unit was collecting high altitude air samples to look for evidence of Soviet nuclear tests when it was withdrawn from Asia after the May 1960 U-2 incident.

Detachment G pilots began using the unmarked Taiwanese "Detachment H" U-2 for North Vietnam overflights in February 1962, but as tactical intelligence became more important, after the Gulf of Tonkin Resolution of August 1964 SAC took over all U-2 missions in Indochina. In late November 1962, Detachment G was deployed to Ta Khli, Thailand, to carry out overflights of the Chinese-Indian border area after Indian Prime Minister Jawaharlal Nehru requested military aid following the Sino-Indian War in October–November 1962. In 1963, India agreed to an American request for a permanent U-2 base for Soviet and Chinese targets, offering Charbatia, although it was only briefly used and Ta Khli remained Department G's main Asian base. After the Vietnamese cease fire in January 1973 prohibited American military flights, CIA pilots again used the unmarked Detachment H U-2 over North Vietnam during 1973 and 1974.

In 1963, the CIA started project Whale Tale to develop carrier-based U-2Gs to overcome range limitations. During development of the capability, CIA pilots took off and landed U-2Gs on the aircraft carrier USS Ranger (CV-61) and other ships. The U-2G was used only twice operationally. Both flights occurred from USS Ranger in May 1964 to observe France's development of an atomic bomb test range at Moruroa in French Polynesia.

In early 1964, the Strategic Air Command (SAC) sent a detachment of U-2s from the 4080th to South Vietnam for high altitude reconnaissance missions over North Vietnam. On 5 April 1965, U-2s from the 4028th SRS (Strategic Reconnaissance Squadron) took photos of SAM-2 sites near Hanoi and Haiphong harbor. On 11 February 1966, the 4080th Wing was redesignated the 100th Strategic Reconnaissance Wing (100 SRW) and moved to Davis-Monthan AFB, Arizona. The SRS detachment at Bien Hoa AB, South Vietnam, was redesignated the 349th SRS.

The only loss of a U-2 during combat operations occurred on 8 October 1966, when Major Leo Stewart, flying with the 349th Strategic Reconnaissance Squadron, developed mechanical problems high over North Vietnam. The U-2 managed to return to South Vietnam where Stewart ejected safely. The U-2 crashed near its base at Bien Hoa. In July 1970, the 349th SRS at Bien Hoa moved to Thailand and was redesignated the 99th SRS, remaining there until March 1976.

In 1969, the larger U-2Rs were flown from the aircraft carrier USS America (CV-66). The U-2 carrier program is believed to have been halted after 1969.



In August 1970, two U-2Rs were deployed by NRO to cover the Israeli-Egypt conflict under the code name EVEN STEVEN.

In June 1976, the U-2s of the 100 SRW were transferred to the 9th Strategic Reconnaissance Wing (9 SRW) at Beale Air Force Base, California, and merged with SR-71 aircraft operations there. When theStrategic Air Command(SAC) was disestablished in 1992, the wing was transferred to the new Air Combat Command(ACC) and redesignated the 9th Reconnaissance Wing (9 RW).

In 1977, a U-2 was retrofitted with an upward-looking window so that it could be used for high altitude astronomical observations of the cosmic microwave background (CMB). This experiment was the first to measure definitively the motion of the galaxy relative to the CMB, and established an upper limit on the rotation of the universe as a whole.

In 1984, during a major NATO exercise, Royal Air Force Flight Lieutenant Mike Hale intercepted a U-2 at a height of 66000 ft, where the aircraft had previously been considered safe from interception. Hale climbed to 88000 ft in his Lightning F3.

In 1989, a U-2R of 9 RW, Detachment 5, flying out of Patrick Air Force Base, Florida successfully photographed a space shuttle launch for NASA to assist in identifying the cause of tile loss during launch discovered in the initial post-Challenger missions.

On 19 November 1998, a NASA ER-2 research aircraft set a world record for altitude of 20479 m in horizontal flight in the 12000 to 16000 kg weight class.

Recent use and planned retirement
The U-2 remains in front-line service more than 50 years after its first flight despite the advent of surveillance satellites. This is due primarily to its ability to direct flights to objectives at short notice, something that satellites cannot do. The U-2 has outlasted its Mach 3 SR-71 replacement, which was retired in 1998.

A classified budget document approved by the Pentagon on 23 December 2005 called for the termination of the U-2 program no earlier than 2012, with some aircraft being retired by 2007. In January 2006, Secretary of Defense Donald Rumsfeld announced the pending retirement of the U-2 fleet as a cost cutting measure, and as part of a larger reorganization and redefinition of the U.S. Air Force's mission that includes the elimination of all but 56 B-52s and a complete reduction in the F-117 Nighthawk fleet. Rumsfeld said that this will not impair the Air Force's ability to gather intelligence, which will be done by satellites and a growing supply of unmanned RQ-4 Global Hawk reconnaissance aircraft.



Retirement of the U-2 has been delayed by gaps in capability if the fleet was removed from service. In 2009, the Air Force stated that it planned to extend the U-2 retirement from 2012 until 2014 or later to allow more time to field the RQ-4 Global Hawk as a replacement. Beginning in 2010, the RQ-170 Sentinel began replacing U-2s operating from Osan Air Base, South Korea.

Upgrades late in the War in Afghanistan gave the U-2 greater reconnaissance and threat-detection capability. As of early 2010, U-2s from the 99th Expeditionary Reconnaissance Squadron have flown over 200 missions in support of Operations Iraqi Freedom and Enduring Freedom; as well as Combined Joint Task Force – Horn of Africa.

A U-2 was stationed in Cyprus in March 2011 to help in the enforcement of the no-fly zone over Libya, and a U-2 stationed at Osan Air Base in South Korea was used to provide imagery of the Japanese nuclear reactor damaged by the 11 March 2011 earthquake and tsunami.

In March 2011, it was projected that the U.S.'s fleet of 32 U-2s would be operated until 2015. The Obama administration requested $91 million to maintain the U-2 program. In 2011, the U.S. Air Force intended to replace the U-2s with RQ-4s before fiscal year 2015. Proposed legislation would require that its replacement have lower operating costs before the U-2 could be retired. In January 2012, it was reported that Air Force plans to end the Northrop Grumman RQ-4 Global Hawk Block 30 program and extend the U-2 fleet in service until c. 2023.

United Kingdom
After training in Texas, a group of Royal Air Force (RAF) U-2 pilots arrived in Turkey in November 1958, shortly after the CIA's Detachment B from Adana provided valuable intelligence during the 1958 Lebanon crisis, which both the United States and United Kingdom were involved in. Since the September 1956 disclosure of Mediterranean photographs, the United Kingdom had (except during the Suez Crisis) received U-2 intelligence. The CIA and Eisenhower viewed using British pilots as a way of increasing plausible deniability for the flights, and the CIA saw British participation as a way of obtaining additional Soviet overflights that the president would not authorize. The United Kingdom gained the ability to target flights toward areas of the world the United States was less interested in, and possibly avoid another Suez-like interruption of U-2 photographs.

Although the RAF unit operated as part of Detachment B, the United Kingdom formally received title to the U-2s their pilots would fly, and Eisenhower wrote Prime Minister Harold Macmillan that because of the separate lines of authority, the nations were conducting "two complementary programs rather than a joint one". A secret MI6 bank account paid the RAF pilots, whose cover was employment with the Met Office. While most British flights occurred over the Middle East during the two years the United Kingdom program existed, two missions over Soviet missile test sites were very successful. Like Eisenhower, Macmillan personally approved the Soviet overflights. The British direct involvement in overflights ended after the May 1960 U-2 incident; although four pilots remained stationed in California until 1974, the CIA's official history of the program stated that "RAF pilots never again conducted another overflight in an Agency U-2." In 1960 and 1961 the first four pilots received the Air Force Cross.

Taiwan (Republic of China)


Taiwan (Republic of China, or ROC) flew U-2 missions mostly over the People's Republic of China (PRC). Since the 1950s, the Republic of China Air Force had used the RB-57D aircraft for reconnaissance missions over the PRC, but suffered two losses when MiG-17s and SA-2 surface-to-air missiles were able to intercept the aircraft.

The USAF desired to provide the U-2 to Taiwan. A group of ROC pilots trained to fly the aircraft in 1959, but the CIA opposed exporting the U-2 because it would affect the CIA's cover story. After the May 1960 incident revealed the aircraft's existence, however, Eisenhower approved the transfer because ROC pilots flying ROC aircraft could not be formally connected to the United States. The CIA called the two U-2s that arrived in Taoyuan Air Base "Detachment H"; one aircraft was left unpainted for CIA use. Both the American and Taiwanese governments approved each flight, and the United States processed the film and gave copies to the ROC. Overflights of China began on 12 January 1962 with a visit to the Shuangchengzi missile test range; future flights photographed the Lanchou nuclear test site and air bases at Kunming. The first loss occurred in September, when the PRC shot down a U-2 near Lushan and captured its pilot. The United States denied PRC accusations of involvement in the ROC flights, noting that the previous Eisenhower administration had sold the U-2s to Taiwan. This was a cover story, however, as the CIA maintained Detachment H's U-2s and replaced them as necessary, and CIA pilots from Detachment G began using Detachment H's unmarked U-2 for flights over North Vietnam in February 1962.

The demand for intelligence on the Chinese nuclear program grew but so did the number of PRC SAM sites and use of the Fan Song radar, and ROC overflights became more dangerous. Two more ROC U-2s were lost in 1963 and 1964, and the Taiwanese demanded improved electronic countermeasures (ECM) equipment. Detachment H's U-2s had the System XII radar detector but not the sophisticated System XIII radar jammer, because the United States Department of Defense feared its loss to the PRC. The need for intelligence on the Chinese nuclear program was so great that the Defense Department agreed to install improved ECM equipment, but insisted that pilots not turn System XIII on until System XII detected FAN SONG. After another ROC U-2 was lost in circumstances that remain classified, Taiwan refused to conduct further overflights unless its pilots could use System XIII whenever over the PRC. All U-2 PRC overflights ended in 1968, however, because the SA-2 missile and MiG-21 interceptors were now too dangerous. In 104 overflights, five U-2s had been lost, with two pilots killed and three captured. Detachment H still conducted flights near the Chinese border; the PRC continued to attempt to shoot the U-2s down but failed. All ROC Detachment H operations ended in March 1972, the month that President Richard Nixon visited China.

In 1958, ROC and American authorities reached an agreement to create the 35th Squadron, nicknamed the Black Cat Squadron, composed of two U-2Cs in Taoyuan Airbase in northern Taiwan, at an isolated part of the airbase. To create misdirection typical of the time, the unit was created under the cover of high altitude weather research missions for ROCAF. To the U.S. government, the 35th Squadron and any U.S. CIA/USAF personnel assigned to the unit were known as Detachment H on all documents. But instead of being under normal USAF control, the project was known as Project Razor, and was run directly by CIA with USAF assistance.

Each of the 35th Squadron's operational missions had to be approved by both the U.S. and the Taiwan/ROC presidents beforehand. To add another layer of security and secrecy to the project, all U.S. military and CIA/government personnel stationed in Taoyuan assigned to Detachment H were issued official documents and ID with false names and cover titles as Lockheed employees/representatives in civilian clothes. The ROCAF pilots and ground support crew would never know their U.S. counterparts' real names and rank/titles, or which U.S. government agencies they were dealing with.

A total of 26 of 28 ROC pilots sent to the U.S. completed training between 1959 and 1973, at Laughlin Air Force Base, Texas. On the night of 3 August 1959, a U-2 on a training mission, out of Laughlin AFB, Texas, piloted by Major Mike Hua of ROC Air Force, made a successful unassisted nighttime emergency landing at Cortez, Colorado, that was later known as Miracle at Cortez, and Major Hua was later awarded the U.S. Air Force Distinguished Flying Cross for saving the top secret aircraft.

In July 1960, the CIA provided the ROC with its first two U-2Cs, and in December the squadron flew its first mission over mainland China. Other countries were also covered from time to time by the 35th Squadron, such as North Korea, North Vietnam and Laos, but the main objective of the ROC 35th Squadron was to conduct reconnaissance missions assessing the PRC's nuclear capabilities. For this purpose the ROC pilots flew as far as Gansu and other remote regions in northwest China. Some of the missions, due to mission requirements and range, plus to add some element of surprise, had the 35th Squadron's U-2s flying from or recovered at other U.S. air bases in Southeast Asia and Eastern Asia, such as K-8 (Kunsan) in South Korea, or Tikhli in Thailand. All U.S. airbases in the region were listed as emergency/ alternate recovery airfields and could be used besides the 35th Squadron's home base at Taoyuan airbase in Taiwan. Initially, all film taken by the Black Cat Squadron would be flown to Okinawa or Guam for processing and development, and the U.S. forces would not share any of the mission photos with Taiwan. Only in late 1960s did the USAF agree to share a complete set of mission photos and help Taiwan set up a photo development and interpretation unit at Taoyuan AB.

In 1968, the ROC U-2C/F/G fleet was replaced with the newer U-2R. However, with the coming of the Sino-Soviet split and the rapprochement between the U.S. and the PRC, the ROC U-2 squadron stopped entering Chinese airspace, and instead only conducted electronic intelligence-gathering plus photo-reconnaissance missions with new Long Range Oblique Reconnaissance (LOROP) cameras on the U-2R while flying over international waters. The last U-2 aircraft mission over mainland China took place on 16 March 1968. After that, all missions had the U-2 aircraft fly outside a buffer zone at least 20 nmi around China.

During his visit to China in 1972, U.S. President Richard Nixon promised the Chinese authorities to cease all reconnaissance missions near and over China, though this was also made practical because U.S. photo satellites by 1972 were able to provide better overhead images without risking losing aircraft and pilots, or provoking international incidents. The last 35th Squadron mission was flown by Sungchou "Mike" Chiu on 24 May 1974.

At the end of ROC's U-2 operations, out of a total of 19 U-2C/F/G/R aircraft operated by the 35th Squadron from 1959 to 1974, 11 were lost. The squadron flew a total of about 220 missions, with about half over mainland China, resulting in five aircraft shot down, with three fatalities and two pilots captured, and another six U-2s lost in training with six pilots killed. On 29 July 1974, the two remaining U-2R aircraft in ROC possession were flown from Taoyuan AB in Taiwan to Edwards AFB, California, US, and turned over to the USAF.

Primary list

 * Sub-section source: Aerospaceweb.org


 * U-2A: Initial production, single-seat; J57-P-37A engine; 48 built
 * U-2B: Two-seat trainer; J57-P-31 engine; five built
 * U-2C: Enhanced single-seat model with J75-P-13 engine and modified engine intakes
 * U-2D: Enhanced two-seat trainer
 * U-2E: Aerial refueling capable, J57-powered
 * U-2F: Aerial refueling capable, J75-powered
 * U-2CT: Enhanced two-seat trainer rebuilt from U-2D airframes with relocation of the seats; six known converted
 * U-2G: A-models modified with reinforced landing gear, added arresting hook, and wing spoilers for U.S. Navy carrier operations; three converted
 * U-2H: Aircraft carrier capable, aerial refueling capable
 * U-2R: Re-designed enlarged airframes with underwing pods and increased fuel capacity; 14 built.
 * U-2RT: Enhanced two-seat R-model trainer; one built.
 * U-2EPX: Proposed U.S. Navy maritime surveillance R-model; two built
 * WU-2: Atmospheric/weather research WU-model
 * TR-1A: A third production batch of U-2R aircraft built for high-altitude tactical reconnaissance missions with side-looking radar, new avionics, and improved ECM equipment; 33 built. Re-designated U-2S after the fall of the Soviet Union.
 * TR-1B: Two TR-1A airframes completed as two-seat conversion trainers
 * ER-2: Two TR-1A airframes, AF Ser. No. 80-1063, and Ser. No. 80-1097, are modified as an Earth resources research aircraft, moved from USAF to NASA and operated by the NASA High-Altitude Missions Branch, Ames Research Center. NASA flies Ser. No. 80-1097 as N609NA and Ser. No. 80-1063 as N806NA
 * U-2S: New redesignation for the TR-1A; updated with a General Electric F118 engine, improved sensors, and addition of a GPS receiver; 31 converted
 * TU-2S: New redesignated TR-1B two-seat trainer with improved engine; five converted

U-2E/F/H details


In May 1961, in a little-known attempt to extend the U-2's already considerable range, Lockheed modified six CIA U-2s and several USAF U-2s with aerial refueling equipment which allowed the aircraft to receive fuel from either the KC-97 or from the KC-135. This extended the aircraft's range from approximately 4000 to 8000 nmi and extended its endurance to more than 14 hours. The J57-powered U-2Bs were re-designated U-2E and the J75-powered U-2Cs were redesignated U-2F. Each modified U-2 also included an additional oxygen cylinder. However, pilot fatigue was not considered, and little use was made of the refueling capability. The one and only U-2H was both air refueling-capable and carrier-capable.

U-2R/S details
The U-2R, first flown in 1967, is significantly larger and more capable than the original aircraft. A tactical reconnaissance version, the TR-1A, first flew in August 1981. A distinguishing feature of these aircraft is the addition of a large instrumentation "superpod" under each wing. Designed for standoff tactical reconnaissance in Europe, the TR-1A was structurally identical to the U-2R. The 17th Reconnaissance Wing, Royal Air Force Station Alconbury, England used operational TR-1As from 1983 until 1991. The last U-2 and TR-1 aircraft were delivered to the U.S. Air Force in October 1989. In 1992 all TR-1s and U-2s (all U-2Rs) were designated U-2Rs. The two-seat trainer variant of the TR-1, the TR-1B, was redesignated as the TU-2R. After upgrading with the F-118-101 engine, the former U-2Rs were designated the U-2S Senior Year.

ER-2 details


A derivative of the U-2 known as the ER-2 (Earth Resources −2), in NASA's white livery, is based at the Dryden Flight Research Center and is used by NASA for high-altitude civilian research including Earth resources, celestial observations, atmospheric chemistry and dynamics, and oceanic processes. Ironically, these were some of the specified "missions" of the original U.S. government cover-up. Programs using the aircraft include the Airborne Science Program, ERAST and Earth Science Enterprise. Landings are assisted by another pilot at speeds exceeding 120 mph in a chase car.

Operators

 * United States
 * United States Air Force
 * 9th Reconnaissance Wing, Beale Air Force Base, California
 * 1st Reconnaissance Squadron
 * 99th Reconnaissance Squadron
 * 5th Reconnaissance Squadron
 * National Aeronautics and Space Administration, Moffett Federal Airfield, California and Dryden Flight Research Center / Edwards Air Force Base, California
 * Central Intelligence Agency - 1956-1974
 * Detachment A, Germany
 * Detachment B, Turkey
 * Detachment C, Japan
 * Detachment G, California


 * Royal Air Force - 1958-1960
 * CIA Detachment B, Turkey
 * CIA Detachment B, Turkey


 * Republic of China Air Force – operated U-2s during 1960–1974.
 * 35th Black Cat Squadron
 * 35th Black Cat Squadron

China

 * U-2C
 * 56-6691 - wreckage is on display at the Military Museum of the Chinese People's Revolution, Beijing. It has been re-assembled and is on display in the aircraft exhibit hall. This airframe, flown by a pilot of the Republic of China Air Force, which was shot down on 10 January 1965, southwest of Beijing by a SA-2 missile.

Cuba

 * U-2F
 * 56-6676 - wreckage is on display at three museums in Cuba. It was flown by Major Rudolf Anderson, USAF, and was shot down during the Cuban Missile Crisis on 27 October 1962 by a Soviet-supplied S-75 Dvina (NATO designation SA-2 Guideline) surface-to-air missile near Banes, Cuba. One of the engine intakes is at the Museo Girón atGirón village, in the province of Matanzas, at the entrance to Bahia de Cochinos, or Bay of Pigs. The engine and portion of the tail assembly from the U-2 is at the Museum of the Revolution in Havana. The right wing, a portion of the tail assembly, and front landing gear are at the Fortaleza de San Carlos de la Cabaña, or La Cabaña, Havana. The two latter groups of parts were previously displayed at the Museo del Aire, Havana.

Norway

 * U-2C
 * 56-6953 - Norwegian Aviation Museum, Bodø.

Russia

 * U-2C
 * 56-6693 - wreckage is on display at the Moscow Military Museum. It was flown by Francis Gary Powers, which was shot down on 1 May 1960 near Sverdlovsk (now Ekaterinburg).

United Kingdom

 * U-2CT
 * 56-6692 - Imperial War Museum Duxford.

United States

 * U-2A
 * 56-6722 - National Museum of the United States Air Force, Wright-Patterson AFB, Ohio.
 * U-2C
 * 56-6680 - National Air and Space Museum in Washington, DC.
 * 56-6701 - Strategic Air and Space Museum, near Offutt AFB in Ashland, Nebraska.
 * 56-6707 - Laughlin AFB, Texas.
 * 56-6716 - Davis-Monthan AFB, Arizona.
 * U-2D
 * 56-6682 - Museum of Aviation, Robins AFB, Georgia.
 * 56-6714 - Beale AFB, California.
 * 56-6721 - Production Flight Test Installation Air Force Plant 42 in Palmdale, California.

Notable appearances in media
In the television series Call to Glory (ABC, 1984–1985), the U-2 was the "main ride" of U.S. Air Force Colonel Raynor Sarnac from the October 1962 Cuba Crisis to 1979.

The U-2 also appears prominently in the movie Thirteen Days (2000). On the BBC program James May at the Edge of Space (2009), James May of Top Gear fame, goes on a flight in a U-2. In the television series, Quantum Leap, during episodes "Honeymoon Express" and "Lee Harvey Oswald", the aircraft is featured in the storylines.

The image of a U-2 was used on the cover of the band Negativland's controversial 1991 EP titled U2.