Over 250 missions in late 1950s did more than take photos:
Secondary purpose was to acquire electronic and communications intelligence on the Soviet target
Document releases begin to flesh out still-highly classified U-2 SIGINT program
Over 250 missions in late 1950s did more than take photos:
Secondary purpose was to acquire electronic and communications intelligence on the Soviet target
Document releases begin to flesh out still-highly classified U-2 SIGINT program
By James E. David*
Washington, D.C., March 8, 2022 – Central Intelligence Agency (CIA) U-2 reconnaissance aircraft flew more than 250 overflight and peripheral missions in Europe, the USSR, Mideast, and the Far East from June 1956 through 1959. Photographic intelligence was the program’s primary objective, and the planes carried one of a series of increasingly capable cameras. Both the films and much of the intelligence derived therefrom have been declassified and covered in the open literature.[1]
Much less well-known is that the secondary objective was signals intelligence (SIGINT), which included electronic intelligence (ELINT) and communications intelligence (COMINT). On every mission during the 1950s, CIA U-2s carried one or more SIGINT sensors. The two sensors initially flown had limited capabilities. But the CIA developed more sophisticated ones quickly.
Unfortunately, only a small number of documents on the SIGINT effort have been declassified. They disclose the technical details of the sensors, the dates of service, the targets in general, the raw intelligence acquired on selected missions, and some other limited information. However, the vast majority of data on the intelligence collected and its contributions to satisfying ELINT and COMINT requirements remains classified. Not surprisingly, there is little treatment of the early CIA U-2 SIGINT efforts in the open literature.
To help fill the gap, this Electronic Briefing Book presents much of what is known about the SIGINT operations. It is long past the time that the CIA, National Security Agency, and other organizations re-review the records previously released in part and the numerous records withheld in their entirety to enable more of this important story to be told.
President Dwight D. Eisenhower approved the joint CIA-Air Force proposal to build the high-altitude U-2 reconnaissance aircraft in November 1954. Officials believed that its operating altitude of 70,000 feet, far higher than any other reconnaissance aircraft, would make it invulnerable to detection by Soviet air defense radars for several years and successful attack for a somewhat longer period [Documents 1 and 2].[2]
This protection would enable the U-2 to conduct overflights of the Soviet Union and help fill critical intelligence gaps. The most significant shortfalls concerned the long-range bomber force, nuclear weapons program, ballistic missile program, and the air defense system [Document 3].[3]
Officials soon created the AQUATONE special security control system to cover the existence of the program and its research and development, testing, staging, security, operations, and other details [Document 4]. AQUATONE was replaced by CHALICE in 1958. The officials also established the TALENT special security control system to cover the raw and finished intelligence from the program.[4]
The U-2’s primary mission was photographic intelligence. Three new cameras – the A-1, A-2, and B - were developed for the U-2. All were more capable than any existing aerial cameras. Because of its superior performance, the B camera was the only one used from late 1958 on. Photographic targets included military airfields, aircraft manufacturing plants, missile testing and deployment complexes, missile manufacturing facilities, radar sites, naval bases and shipyards, ground forces installations, communication sites, and nuclear production, storage, and testing facilities. This imagery was essential to accurately assess Soviet offensive and defensive capabilities and determine the targets to be attacked in case of war.[5]
Air Force and Navy reconnaissance aircraft flew hundreds of peripheral missions with cameras annually by the mid-1950s, but they of course did not acquire photography of the vast interior. The Air Force (and to a lesser extent, the Navy) had also started conducting overflights in the late 1940s to collect imagery. However, they were limited in number and coverage because the aircraft flew at lower altitudes, were vulnerable to Soviet air defenses, and did not have the range to fly deep-penetration missions. Additionally, the Soviets frequently lodged strong protests and every flight risked creating an international incident. Because of these factors and the impending onset of U-2 overflights, military overflights essentially ended after May 1956.[6]
The U-2’s secondary mission was SIGINT to acquire ELINT or COMINT. During the 1950s, ELINT included the interception of a wide range of radars and processing and analyzing the intercepts to determine their location and technical characteristics such as frequencies, modulation, and pulse repetition rate. These included early warning radars that determined the distance and direction of aircraft, height finding radars that determined their altitude, ground control intercept radars that directed fighters, and fire control radars that guided the firing of surface-to-air missiles and anti-aircraft artillery. The ELINT intelligence was incorporated into Radar-Order-of-Battle and Electronic-Order-of-Battle reports, which were used to plan the safest ingress and egress routes for combat aircraft penetrating the USSR and to develop electronic countermeasures.[7]
All Soviet radars during the latter part of the 1950s utilized frequencies above the high frequency range. The majority employed frequencies in the very high frequency range. Others were designated S-band radars that operated in the upper part of the ultra-high or lower part of the super high frequency ranges. There was also one L-band radar that used the lower part of the ultra-high frequency range. The propagation characteristics of these above high frequencies required in almost every case that the ELINT sensor be in the line of sight of the radars to acquire intercepts. Except in the cases of airborne and shipborne radars, aircraft were the only platform that could effectively perform this mission. Many Air Force and Navy reconnaissance aircraft conducting peripheral reconnaissance flights intercepted radars located at or near the borders but not from the vast interior of the USSR.[8]
Electronic intelligence also included the interception and processing of telemetry downlinked by missiles to ground stations during test flights. Telemetry is the measurement of variables such as temperatures, acceleration, vibrations, and propellant levels. Technical personnel of the country conducting the test used it in monitoring the vehicles before launch and during flight and thereby determined which systems and components worked well and which did not and why. For the United States, analysis of the data was essential to determining the performance characteristics of the missiles, such as the type of propulsion and guidance systems, range, and payload capacity. Because the Soviets used above high frequencies for telemetry, ELINT sensors at ground stations or on ships and aircraft had to be in the line of sight of the missile to intercept it.[9]
Human sources in the late 1940s began providing intelligence on the Soviets’ only missile testing complex – Kapustin Yar, about 100 miles east of Stalingrad – and the short- and medium-range missile tests there. The missiles flew eastward and impacted in one of several areas. During the early 1950s, COMINT started furnishing additional intelligence including intercepts of lengthy pre-launch countdowns (although analysts could not initially distinguish between practice and actual countdowns), communications of transport flights in and out of Kapustin Yar and communications between Kapustin Yar and the downrange stations. The COMINT was acquired by ground stations operated by the three service cryptologic agencies – Air Force Security Service, Army Security Agency, and Naval Security Group – in Turkey and likely other countries.[10]
The Army Security Agency’s ground station at Sinop, Turkey, collected the first telemetry intercept (from a SS-1 short-range missile) in June 1956. The Air Force Security Service soon started acquiring telemetry from missiles launched at Kapustin Yar at its ground station at Samsun, Turkey. It also built a specialized radar at Diyarbakir, Turkey, during 1955 to detect and track missiles launched from the complex. Although the details remain classified, it appears that Air Force RB-57Ds and Navy P4M Mercators and A3D Skywarriors targeted telemetry from missiles launched at Kapustin Yar. From mid-1953 to September 1957, radar intelligence and COMINT identified at least 275 launches from the complex to ranges of about 75, 150, 300, 650, and 950 nautical miles. These sources continued identifying numerous tests in the following years. Although it is unknown what platforms obtained them, 18 intercepts were acquired in 1956 and increasing numbers in the following years. Undoubtedly based on these intercepts, along with radar intelligence and ground photography of selected missiles during the November 1957 Moscow parade, by late 1959 the intelligence agencies had determined with varying degrees of certainty the ranges, guidance systems, accuracy, warhead weights and types, configurations, and propulsion systems of the five short- and medium-range ballistic missiles tested at Kapustin Yar.[11]
Communications intelligence collected by ground stations at various locations beginning in 1955 suggested the construction of additional suspected missile program installations near Novokazalinsk/Dzhusaly in the Kazakh SSR (eventually designated Tyuratam) and at Klyuchi on the Kamchatka Peninsula. By early 1957, additional but still limited COMINT enabled intelligence agencies to identify the former as a possible launch complex for intercontinental ballistic missiles (ICBMs) and satellites and the latter as the terminus of the range for ICBM tests. Two U-2 missions in August 1957 provided the first photography of Tyuratam and confirmed it was a launch site with one completed launch pad and several others under construction. (Tyuratam also served in the early years as the launch facility for all Soviet space shots.) U-2 photography of Klyuchi in June and September 1957 revealed that it was the terminus for ICBM tests.[12]
The few declassified records available demonstrate that the United States had only limited intelligence on activities at Tyuratam during 1957. Evidence of the first ICBM test in August 1957 came from a Soviet press release and the second test the following month from comments made to a French politician by Soviet leader Nikita Khrushchev. Confirmation that Sputnik I in October 1957 and Sputnik II the following month were in orbit came from Soviet press releases after their launches and reports of various commercial and government receiving stations hearing the signals transmitted by them.[13]
The intelligence agencies undertook a massive effort to close the information gap on the Soviet ICBM and space programs, but most of the details remain classified. They took steps to improve COMINT coverage of activities on the Tyuratam range. The Air Force Security Service ground stations at Trabzon, Turkey; Wakkanai, Japan; and Peshawar, Pakistan were soon equipped to acquire telemetry from vehicles launched at Tyuratam. In 1958, the Army Security Agency established a ground station at Shemya in the western Aleutians to collect telemetry from the ICBMs and, after separation, the reentry vehicles during the terminal phase of their flights. The Air Force Security Service soon installed a radar at the site to track the missiles and reentry vehicles during this period. The CIA began operating a ground station in northern Iran in 1959 to acquire telemetry from vehicles launched at Tyuratam. Air Force planes and CIA U-2s conducted peripheral flights along the Soviet borders with Iran and Afghanistan to obtain telemetry intercepts. Around Kamchatka Peninsula and the Pacific Ocean impact area (which the Soviets used in some tests beginning in the fall of 1959), Navy P4M Mercators, A3D Skywarriors, and possibly Air Force planes collected telemetry from ICBMs and, after separation, their reentry vehicles. From August 1957 through the end of 1959, the Soviets tested at least 17 ICBMs (not all successfully). Although it is unknown except in one case what platforms obtained them, four intercepts were acquired in 1958 and 17 the following year. Undoubtedly based on them and radar intelligence, by late 1959 the intelligence agencies had estimated the probable range, propulsion system, configuration, guidance system, accuracy, type of nosecone, and warhead weight of the only ICBM tested to date.[14]
Officials believed at the beginning of the project that the U-2 could also possibly perform COMINT. For many decades, the USSR and every other nation in the world used high frequency systems for most communications. The skywaves bounced off the ionosphere and back to Earth repeatedly, enabling interception to take place thousands of miles away by ground stations and occasionally aircraft and ships. Because the worldwide network of ground stations provided good coverage of Soviet high frequency communications, U-2s targeted the ultra-high frequency communications the Soviets were increasingly using.[15] Use of these ranges required that the COMINT sensor be in line of sight of the transmitter to acquire intercepts. Unless the transmitter was on or near the borders, aircraft were the only platform capable of collecting them.
Selected Soviet ground-to-air and air-to-ground communications in the Far East began transitioning from high frequency to ultra-high frequencies late in the Korean War. The Air Force quickly started an intercept program using a single aircraft. Ground-to-air and air-to-ground communications in other parts of the USSR moved to ultra-high frequencies later in the decade. The Air Force expanded the collection program and began routinely flying the aircraft on peripheral reconnaissance missions to acquire intercepts from the border areas. The Soviets were also starting to employ ultra-high frequency microwave systems for medium- and long-distance communications. These utilized towers spaced approximately 25 to 30 miles apart to receive the signals and relay them to the next tower. Since most of these systems operated in the interior of the USSR, only aircraft conducting overflights could intercept them.[16]
The CIA developed new ELINT sensors for the U-2. The first, System I, primarily intercepted S-band radars and flew on every mission from 1956-1959. Three larger and more capable receivers that intercepted a wider range of radars and telemetry – Systems IV, V, and VI – entered service later. System IV was carried on 17 missions from 1957-1959, System V on three in 1956-1957, and System VI on three in 1957-1958. While Systems IV and V displaced the main camera, System VI did not. Although there are few declassified records on the individual targets and the intelligence acquired, it is widely reported that the sensors provided valuable information. A dedicated COMINT sensor, System III, intercepted selected very high frequencies. It flew on many missions in 1956-1958 but proved ineffective. System VII was designed to acquire telemetry and achieved some success during 23 missions during 1959-1960. As did Systems IV and V, it also displaced the main camera.[17]
----------------------------
* James E. David is curator of national security space programs at the Smithsonian National Air & Space Museum.
Document 01
Annex 6 in History of the Office of Special Activities from Inception to 1969
Top officials and scientific advisors of the Eisenhower Administration had been examining actions the nation could take to improve intelligence collection against the Soviet Union. They strongly supported conducting overflights with high-altitude aircraft to perform both photographic and electronic reconnaissance that were believed to be invulnerable to detection and attack for the near future. One was the existing Air Force Canberra to be modified to fly at around 65,000 feet and the other was a new aircraft to be built to fly at around 70,000 feet. The memorandum asked the president to approve a requirement for the overflights and a program to acquire the aircraft and crews.
Document 02
Annex 8 in History of the Office of Special Activities from Inception to 1969
President Eisenhower met with Director of Central Intelligence Allen Dulles, Secretary of State John Foster Dulles, Secretary of Defense Charles Wilson, and others on the overflight requirement and whether to approve the proposed aircraft programs. He approved them but stated that he wanted to review the project before operations commenced.
Document 03
Annex 10 in History of the Office of Special Activities from Inception to 1969
This proposal requested approval by the director of central intelligence of a covert joint Air Force-CIA project to acquire the CL-282 (later designated the U-2), a new high-altitude reconnaissance aircraft to be developed by Lockheed. Although photographic intelligence was the primary mission, it would also carry ELINT sensors to obtain intelligence on radars. There was also a possibility that COMINT sensors could be placed aboard the aircraft to intercept presently “inaccessible” ultra-high frequency (microwave) links. The director quickly gave his approval.
Document 04
CIA FOIA Electronic Reading Room
The CIA established the interagency Ad Hoc Requirements Committee in early 1956, chiefly to recommend missions and their photographic and SIGINT targets. At this meeting, members learned that the System I ELINT sensor would be available when operations commenced and that the System III COMINT sensor would be available by 1 June. The ELINT requirements promulgated by a joint CIA-DoD committee would be utilized. One copy of the ELINT tapes with the intercepts would be available to the theater command for exploitation, while copies would be sent to the CIA and the newly established interagency National Technical Processing Center for exploitation. The COMINT tapes would be sent to the National Security Agency.
Document 05
Annex 120 in History of the Office of Special Activities from Inception to 1969
This excerpt lists all the CIA U-2 missions from 1956-1960. Among other things, it sets forth the target, type of camera, type of ELINT sensor (when it displaced the camera), and a one-word assessment of the results.
Document 06
Annex 43 in History of the Office of Special Activities from Inception to 1969
This is the only declassified description of the ELINT and COMINT sensors developed during this period.
Document 07
CIA FOIA Electronic Reading Room
This is a brief report on the ELINT collected by the System I sensor on Mission 2023, flown on 10 July 1956 from Germany to Crimea. Although CIA U-2s carried ELINT sensors on every mission during the 1950s, this is one of the few declassified post-mission reports. BOXBRICK was a vehicle-mounted passive device deployed in East Germany that intercepted aircraft radars to determine the plane’s direction and alert early warning radars. WHIFF was a widely deployed antiaircraft fire-control radar, and TOKEN was a common S-band radar used for both early warning and ground control intercept (directing fighters). As indicated at the end, the National Security Agency monitored air defense communications during the flight and reported the results in a “DMR.”
Document 08
CIA FOIA Electronic Reading Room
This is a photographic intelligence report published a month after Mission 2013, the first overflight of the Soviet Union. The ELINT report based on the System I sensor and the COMINT report based on the System III sensor (if the flight carried it) remain classified.
Document 09
CIA FOIA Electronic Reading Room
This memorandum was probably prepared in the fall of 1956 during a dispute between the CIA and Air Force concerning stationing U-2s at an Air Force base in Japan to provide coverage of the Far East. The Air Force claimed that the new B-57Ds it would fly from Japan could acquire the intelligence that U-2s did, and that stationing U-2s at the base would interfere with Air Force operations. However, as set forth in this document, the U-2 not only flew higher but also was a better collector of photographic intelligence and carried SIGINT sensors that the B-57D did not. After several months, the dispute was resolved and U-2s were deployed at the base.
Document 10
CIA FOIA Electronic Reading Room
This memorandum concerns developing procedures under which the National Security Agency would inform the CIA during missions of relevant air defense communications it was monitoring to determine if there was any immediate threat to them. Although it is not known for certain that such procedures were implemented, it is very likely that they were.
Document 11
CIA FOIA Electronic Reading Room
This heavily redacted document discusses the financing of equipment to improve the processing of SIGINT collected by Systems I, III, IV, and V. Some of the hardware would go to the interagency National Technical Processing Center and some to the CIA’s internal ELINT processing center at Barton Hall, then located in West Potomac Park, near the Lincoln Memorial in Washington, D.C.
Document 12
CIA FOIA Electronic Reading Room
This document reflects the Ad Hoc Committee’s judgement that penetration missions should collect photography and SIGINT from Systems I and III sensors that do not displace the camera. The memo indicates the photographic intelligence is more important than SIGINT. Accordingly, penetration flights should not carry the System V sensor that displaces the camera. Upcoming peripheral missions should focus on intelligence on air defenses which is obtained from SIGINT sensors.
Document 13
CIA FOIA Electronic Reading Room
This is another of the small number of declassified post-mission ELINT and COMINT reports. It summarizes the results from Mission 6002, an abbreviated 8 June 1957 flight from Alaska to the Kamchatka Peninsula. Although the System I sensor intercepted U.S. S-band radars in Alaska, it did not collect any Soviet S-band radar signals. This was apparently because no such radars were deployed in the Soviet Far East. Similarly, the System III sensor intercepted U.S. very high frequency communications from Alaska but no Soviet ones.
Document 14
CIA FOIA Electronic Reading Room
This is another of the few declassified post-mission ELINT reports. It sets forth the results from Mission 4036, a 5 August 1957 flight from Japan over China and Mongolia. The System I sensor did not intercept any S-band radars.
Document 15
CIA FOIA Electronic Reading Room
This heavily redacted draft memorandum states that the intercepts acquired by System I sensors, particularly on penetration missions, have been analyzed and incorporated in finished intelligence reports by the National Technical Processing Center and other organizations. (All these reports are still classified today.) However, it asks whether System I and other sources have collected all the air defense data available. Additionally, it asks, since System I cannot be programmed currently, whether it should be modified to be programmable or whether a new programmable sensor should be used.
Document 16
CIA FOIA Electronic Reading Room
The National Security Agency reported to the Committee that it had completed the readout of System III intercepts from four unspecified missions, but that their value was minimal and that it would not publish any reports. The Committee did not recommend the use of System V in peripheral Far East flights as it had not established any priority requirements for the expected intelligence. However, the Committee would not object if it were flown for operational reasons.
Document 17
CIA FOIA Electronic Reading Room
The Committee agreed to accept the ELINT requirements report of its Subcommittee on ELINT Requirements (which remains classified) but concluded that the requirements would not be of the highest priority and be subject to review. The best time for the review would be after the final analysis of the existing System IV tapes. (System IV had flown on four missions to this point – Mission 2037 on 11 October 1957 from Germany over the Barents Sea (to collect ELINT from Soviet naval maneuvers), Mission 4065 on 6 November 1957 from Turkey over the Black Sea, Mission 4066 on 14 November 1957 from Turkey to the Iranian-Soviet border, and Mission 4069 on 9 January 1958 from Turkey over the Black Sea.) A shortage of readout equipment slowed down the processing and analysis because the priority had been research and development of the collection equipment.
Document 18
CIA FOIA Electronic Reding Room
This document reports on the progress of the CIA and National Technical Processing Center in processing and analyzing System IV tapes from the first four missions to carry this sensor. The processing and analysis of the tapes was a lengthy and challenging process. Missions 2037 and 4066 acquired 5,800 intercepts of known radars, 1,250 of valid but unidentified signals, and 250 of signals in the “indeterminate class.” It would be several weeks before similar information could be obtained from the Mission 4065 and 4069 tapes. Based on the work to date, the System IV was assessed as being a “versatile sampling system,” but the technical problems with it and the copying and analytical equipment had to be corrected.
Document 19
CIA FOIA Electronic Reading Room
This meeting focused entirely on the ELINT program. The project director had requested the Committee to advise him on the requirements for peripheral collection by System IV. The ELINT staff officer proposed that these missions be conducted against five targets, the highest priority Leningrad and Novaya Zemlya in the Barents Sea, the second Kamchatka Peninsula, the third the northern Siberian coast, the fourth the southern periphery of the Soviet Union, and the fifth ice islands in the Arctic. The Committee agreed with this.
Document 20
CIA FOIA Electronic Reading Room
This memorandum states that the highest priority strategic ELINT objective is guidance systems and telemetry related to guided missiles and atomic energy. In order to acquire this intelligence, System IV must be flown on penetration missions with the possible exception of the targets of Leningrad, the Barents Sea, Kamchatka, and the northern Siberian coast. Accordingly, it recommends that the CIA process and analyze System IV tapes for this intelligence and then turn them over to the National Technical Processing Center and Strategic Air Command so they can obtain intelligence on radars in the tapes.
Document 21
CIA FOIA Electronic Reading Room
This memorandum describes the various combinations of ELINT sensors flown – Systems VI and III; Systems V, III, and a portion of VI; Systems IV, III, and a portion of VI.
Document 22
CIA FOIA Electronic Reading Room
This is one of the few declassified National Security Agency reports on the COMINT collected by System III. Mission 1749 flew on 9 May 1958 from the Philippines to Indonesia. The only COMINT intercepts were English and Chinese FM and television stations, English airways communications, and several unspecified beacons. They were of no intelligence value.
Document 23
CIA FOIA Electronic Reading Room
This heavily redacted document states that no U.S. ELINT equipment has the intercept capabilities of System IV supplemented by Systems I and III. Use of System IV provides the best assurance of detecting existing and new Soviet electronic systems. Peripheral missions against Leningrad and the White Sea region are recommended. Unfortunately, the results from the small number of System IV missions to date are redacted.
Document 24
CIA FOIA Electronic Reading Room
This document discusses the continuing issues with the processing and analysis of System IV tapes. After initial processing and analysis by the CIA, the original tape goes to the National Technical Processing Center. This organization focuses on unique signals. It sends a duplicate tape to the Strategic Air Command, which focuses on obtaining intelligence for its Electronic-Order-of-Battle and Radar-Order-of-Battle publications. These publications are issued every 48 hours. Air Force units in Europe and the Far East will soon receive processing and analytical equipment to permit them to more quickly obtain Electronic-Order-of-Battle and Radar-Order-of-Battle intelligence.
Document 25
CIA FOIA Electronic Reading Room
DRAGON LADY was the codename for the Strategic Air Command U-2 program, which started flying missions in 1958. Very few records have been declassified on the program, but it is known that many of early missions carried sensors to monitor nuclear detonations under the High Altitude Sampling Program. The first overflights were made in the early 1960s covering parts of Southeast Asia. This document shows the placement of various sensors in the U-2 and the extent of their coverage.
Document 26
Eisenhower Library
This memorandum reflects the continuing concerns of the president with overflights of the Soviet Union. His basic question was whether the intelligence the overflights produced outweighs the increase in tensions they generate. As occurred before and would occur subsequently when he raised these concerns, he never ordered a permanent end to overflights until the shootdown of Gary Powers’ aircraft in May 1960.
Document 27
CIA FOIA Electronic Reading Room
This memorandum describes a joint CIA-Air Force operation that collected telemetry from a 9 June ICBM test flight from Tyuratam. The National Security Agency alerted both agencies six hours prior to the launch so their aircraft could fly from Turkey to the Iranian-Soviet border to acquire the telemetry. The CIA U-2 carried the new System VII sensor. Because the U-2 flew at a higher altitude, the sensor obtained a 30-second intercept of telemetry from the first stage beginning 80 seconds after launch. This was the first telemetry intercepted from the first stage of an ICBM. The Air Force RB-47 detected new telemetry frequencies and acquired an intercept from the second stage. Together, the intercepts enabled more precise analysis of the size, types, and other characteristics of the propulsion systems. A similar operation took place on 18 June to cover a space launch from Tyuratam (the launch failed). Although the analysis of the System VII intercepts and any RB-47 intercepts was not completed, it was believed that they might explain the cause of the failure.
Document 28
CIA FOIA Electronic Reading Room
This memorandum details malfunctions in SIGINT sensors and cameras during September 1959.
[1] Notable accounts include: Robert S. Hopkins III, Spyflights and Overflights: US Strategic Aerial Reconnaissance, 1945-1960 (Hikoki Publications, 2016); Chris Pocock, 50 Years of the U-2: The Complete Illustrated History of the Dragon Lady (Schiffer Publishing, Ltd., 2004); and two recent volumes by Kevin Wright: We Were Never There: Volume 1: CIA U-2 Operations over Europe, USSR, and the Middle East, 1956-1960 (Helion & Co., 2021) and We Were Never There: Volume 2: CIA U-2 Asia and Worldwide Operations 1957-1974 (Helion & Co., Feb 2022).
[2] Memorandum for the President from Allen W. Dulles, “Reconnaissance,” Director, 24 November 1954, and Memorandum of Conference with the President, 24 November 1954, in Helen Kleyla and Robert O’Hern, History of the Office of Special Activities from Inception to 1969 (Directorate of Science and Technology, 1969), Annexes 6 and 8. [See Documents 1 & 2 in this compilation.]
[3] Project Outline, 7 January 1955, Annex 10, in History of the Office of Special Activities. [See Document 3.]
[4] Memorandum on Chalice Security System, 18 September 1958; CIA FOIA Electronic Reading Room.
[5] Ibid. Gregory W. Pedlow and Donald E. Welzenbach, The Central Intelligence Agency and Overhead Reconnaissance, The U-2 and OXCART Programs, 1954-1974 (Washington, D.C.: Central Intelligence Agency, 1992), pp. 48-56.
[6] See, e.g., Robert Hopkins III, Spyflights and Overflights, U.S. Strategic Aerial Reconnaissance, Volume 1: 1945-1960 (Manchester: Hikoki Publications, 2016).
[7] Intelligence Research Project, Summary of Significant Soviet Weapons and Equipment,5 March 1958, pp. 71-75; Commander in Chief, U.S. Pacific Fleet, Sino-Soviet Air Defenses Far East; Soviet Defense Intercept Capability by the Use of Radars, pp. 1.2-1.4; William H. Nance, “ELINT, a Scientific Intelligence System”, Studies in Intelligence, Vol. 12, No. 2 (Spring 1968); Charles A. Kroger, Jr., “ELINT: A Scientific Intelligence Systems”, Studies in Intelligence, Vol. 2, No. 1 (Winter 1958); CIA FOIA Electronic Reading Room.
[8] Ibid.
[9] David S. Brandwein, “Telemetry Analysis”, Studies in Intelligence. Vol. 8, No. 4 (Fall 1964); CIA FOIA Electronic Reading Room.
[10] Thomas R. Johnson, American Cryptology during the Cold War, 1945-1989, Book I: The Struggle for Centralization 1945-1960 (Center for Cryptologic History, National Security Agency, 1995), pp. 121-125. [redacted], The Soviet Land-Based Ballistic Missile Program, 1945-1972 (National Security Agency, 1975), Section II, p. 4 and Section IV, pp. 1-9.
[11] Stanley G. Zabetakis and John F. Peterson, “The Diyarbakir Radar”, Studies in Intelligence, Vol. 8, No. 4 (Fall 1964); Special National Intelligence Estimate 11-8-57, Evaluation of Evidence Concerning Soviet ICBM Test Flights, 18 September 1957, p. 1; National Intelligence Estimate 11-5-59, Soviet Capabilities in Guided Missiles and Space Vehicles, pp. 13-16, 3 November 1959; CIA FOIA Electronic Reading Room. Memorandum from E.V. Murphee, Special Assistant to the Secretary of the Air Force, 1 January 1956, Record Group 340, Entry A-1-1-E, Box #1, National Archives, College Park, Maryland. The Soviet Land-Based Ballistic Missile Program, 1945-1972, Section IV, pp. 1-9. Richard L. Bernard, The Foreign Missile and Space TELEMETRY Collection Story – The First 50 Years, Part One: The 1950s and 1960s (Center for Cryptologic History, National Security Agency, 2004), pp. 9-10, 15, 21, 24.
[12] The Central Intelligence Agency and Overhead Reconnaissance, pp. 127-128, 133-139, 163-170. The Soviet Land-Based Ballistic Missile Program, 1945-1972, Section II, p. 13. National Security Briefing, Latest Soviet Guided Missile Activities, 23 May 1957 and Central Intelligence Bulletin, 5 April 1957; CIA FOIA Electronic Reading Room.
[13] Current Intelligence Bulletin, 28 August 1957, 5 October 1957, 3 November 1957 and Special National Intelligence Estimate 11-8-57; CIA FOIA Electronic Reading Room.
[14] Current Intelligence Bulletin, 27 October 1957, 6 November 1957, 28 March 1959; National Intelligence Estimate 11-5-59; CIA FOIA Electronic Reading Room. The Foreign Missile and Space TELEMETRY Collection Story, pp. 9-10, 15, 21, 24. The Soviet Land-Based Missile Program, Section III, pp. 62-64.
[15] American Cryptology during the Cold War, 1945-1989, Book 1, pp. 111-112. Memorandum of Conference with the President, 24 November 1954 and Memorandum for the President from Allen W. Dulles, Director, “Reconnaissance,” 24 November 1954 [Document 1].
[16] Analysis of AFSS Effort in the Korean Action, June 1950-October 1953 (Historical Division, United States Air Force Security Service), pp. 318-326. American Cryptology during the Cold War, 1945-1989, Book 1, pp. 140-146. Economic Intelligence Report, Intra-Bloc and International Telecommunications of the Sino-Soviet Bloc, 1950-1965, June 1961; CIA FOIA Electronic Reading Room.
[17] Electronic Equipment – U-2 Program, Annex 43, History of the Office of Special Activities.