THE GERMAN ATOMIC BOMB program turned out to be far less successful than U.S. scientists and intelligence officials feared in 1943. By the time of the Nazi defeat in the spring of 1945, German scientists had not even completed a functioning reactor, and were in no position to attempt to build a bomb. There were no German counterparts to Los Alamos, Oak Ridge, or Hanford. Yet the effort to collect and analyze information about what the Germans were doing and what they had accomplished had not been conducted in vain.
During the the latter stages of the war, the Allied intelligence effort provided reassurance that Adolf Hitler would not be able to avert defeat by using a superweapon—that the war would not turn against the Allies at “one minute to midnight,” in the words of OSS officer Howard Dix.1 The effort also had significant benefits for the Cold War. The Allies’ capture of records and personnel, including Heisenberg and other key scientists, kept them out of Soviet hands. In addition, the search for any German attempt to build a bomb constituted a practice run for the far lengthier, more extensive, and more sophisticated program about to unfold to uncover Soviet nuclear secrets.
BEFORE THE END of 1945, the Soviet effort to build an atomic bomb was underway. Operation Borodino, named after the locale where Russian soldiers had halted Napoleon’s advance in 1812, had been propelled forward first by word of U.S. and British activities in the field and then by the destruction of Hiroshima and Nagasaki. Soviet physicists, including Yuli Khariton and Yakov Zeldovich, had learned about fission from the scientific grapevine as well as the journals that told physicists around the world of the discovery. In 1921, at the age of seventeen, Khariton had made such a favorable impression on Nikolai Semenov, the deputy director of the prestigious Physicotechnical Institute in Petrograd (later Leningrad), that Semenov invited him to join the institute. In 1926, Khariton headed for Cambridge University. He returned two years later with a doctorate and established an explosives laboratory at the Institute of Physical Chemistry. Zeldovich, ten years younger than Khariton, also found himself, at seventeen, being invited to work at the physics institute in Leningrad.2
In October 1939 they transmitted two papers to the Soviet Journal of Experimental and Theoretical Physics. The first concluded that a fast-neutron chain reaction in U-238 was not possible, while the second examined the possibility of a slow-neutron chain reaction in natural uranium and concluded that U-235 and heavy water were means of attaining such a reaction. A third paper, on the kinetics of a chain reaction, followed in March. Other papers, by Georgi Flerov and Lev Rusinov and Flerov and Konstantin Petrzhak, explored other important elements of fission.3
Such research spurred Vladimir Vernadskii and Vitali Khlopin to write Nikolai Bulganin, the country’s deputy premier and chairman of the government’s council on the chemical and metallurgical industries. Vernadskii, a Russian mineralogist who had been elected to the Academy of Sciences in 1906, was a pioneer in the study of radioactive materials. Khlopin, a chemist, headed the Leningrad-based Radium Institute. Their July 12, 1940, letter drew Bulganin’s attention to the discovery of fission and its potential. Four days later, the presidium of the Academy of Sciences met to consider the matter and requested a further report from Vernadskii and two academy colleagues.4
On July 30 the academy established the Special Committee on the Uranium Problem to oversee atomic energy research, with Khlopin as chairman. The committee of about a dozen scientists also included Khariton, Vernadskii, Physicotechnical Institute head Abram Ioffe, and Igor Kurchatov. Kurchatov, a contemporary of Khariton, was the son of a surveyor and teacher who had been born in the Chelyabinsk region of the southern Urals in 1903. He had received his undergraduate physics degree in 1923, then enrolled at the Polytechnic Institute in Petrograd. A possible career in shipbuilding was derailed in 1925 when Ioffe invited him to join his institute. In 1932 Kurchatov’s focus shifted to nuclear physics, and between July 1934 and February 1936, he and his coauthors published seventeen papers on artificial radioactivity.5
But the initial, official Soviet investigation of fission would be a short one. On June 22, 1941, less than a year after the commission was established, the German army breached the Soviet frontier and headed for Moscow. Its rapid advance did not allow Soviet scientists the luxury of investigating the mid- or long-term benefits of atomic energy. Instead, they turned their attention to the immediate problem of defeating the invading Nazi army.6
The halt was only temporary. The atomic activities of the Soviet Union’s major allies eventually helped convince Soviet dictator Joseph Stalin to order a resumption of research. In early November 1941, Lavrenti Beria, the head of the People’s Commissariat of Internal Affairs (NKVD), whose responsibilities included foreign espionage, received word from the Soviet embassy in London that scientists in Britain were conducting theoretical work on an atomic bomb employing uranium. Among the London embassy’s sources were British Foreign Office official Donald Maclean and the Treasury’s John Cairncross, both of whom had access to information on the British atomic program. Stalin, not for the first time, was reluctant to believe the NKVD’s foreign spies. But Beria, who himself was suspicious of foreign deception, continued to compile reports until he was able to offer more conclusive proof. Some of that additional information was provided by the Soviet General Staff’s Chief Intelligence Directorate (GRU), whose roster of agents included Klaus Fuchs, a German émigré physicist working in the British program. The information from Fuchs and others justified the Soviet code name for atomic intelligence—Enormoz (Enormous).7
In March 1942, Beria presented Stalin with the additional evidence he had accumulated. Later that year Stalin met with Ioffe, Khlopin, Vernadskii, and Peter Kapitza, who would win a Nobel Prize for his experimental work in low-temperature physics, to discuss the issue. On February 11, 1943, the State Defense Committee approved an atomic energy research and development program. The next month, Stalin selected Kurchatov as the project’s scientific director and head of the vaguely named Laboratory No. 2, which was established in April in the northwest sector of Moscow.8
Kurchatov was still sporting the pharaoh-like beard he had grown while recovering from pneumonia in early 1942, which he promised “no scissors would touch till after victory.” According to a former student and biographer, it hid his “strong, resolute chin.” Bearded or not, Laboratory 2’s director was a “natural leader, vigorous and self-confident,” according to author Richard Rhodes. One of Kurchatov’s contemporaries described him as an individual with a “great sense of responsibility for whatever problem he was working on, whatever its dimensions might have been,” and recalled that he “would sink his teeth into us and drink our blood until we’d fulfilled [our obligations].”
His laboratory had a dual mission: designing a nuclear reactor to determine the feasibility of a nuclear chain reaction and developing methods (including gaseous diffusion) for separating U-235 from natural uranium. The mission expanded in the spring of 1943 to include the production of plutonium and the investigation of its properties, after Kurchatov examined intelligence from the Allied bomb program revealing that plutonium rather than U-235 was the most promising path to development of a bomb.9
The August 1945 attacks on Hiroshima and Nagasaki demonstrated the success of the Allied bomb program and led Stalin to implore his scientists to give the Soviet state a similar capability. He told Kurchatov and other senior officials, “Comrades—a single demand of you. Get us atomic weapons in the shortest possible time. As you know Hiroshima has shaken the whole world. The balance has been broken. Build the bomb—it will remove the great danger from us!” Later in the month, the State Defense Committee voted to establish the Special Committee on the Atomic Problem, and the Council of People’s Commissars created a First Chief Directorate to organize and manage the bomb program. Beria was named chairman of the committee and chief of the directorate. Stalin gave him two years to produce a bomb.10
The decision meant that more people, money, and equipment would be devoted to the program. In addition, the indigenous Soviet effort would be augmented by the continued flow of espionage material. By 1945, the NKVD and GRU had spies at Los Alamos and several other Allied atomic sites in the United States, Canada, and Britain. David Greenglass, Theodore Hall, and Klaus Fuchs were at Los Alamos, and Allan Nunn May was in the project’s Montreal laboratory. They could tell their Soviet masters about topics, such as implosion, that the official U.S. history of the Manhattan Project, Henry Smyth’s General Account of the Development of Methods of Using Atomic Energy for Military Purposes, released in August 1945, did not. Aside from information, the NKVD provided the human and technical resources required, including labor camp prisoners to expedite uranium-mining operations in Central Asia.11
Still, the Soviet secret police chief faced the same type of tasks and challenges that Leslie Groves had faced: design a bomb, obtain the necessary nuclear material (uranium and/or plutonium), construct the device, and test it. To do so required scientists, laboratories and institutes where they could work, uranium ore, facilities for the conversion of ore into sufficiently enriched uranium or plutonium, installations where bomb components could be constructed and assembled, and a test site. New atomic-related facilities would start to spring up across the Soviet Union.
Kurchatov continued as scientific director from his post at Laboratory No. 2 and assumed responsibility for the construction of an experimental reactor, designated F-1 (for First Physics Uranium Pile), at the site. The number of personnel in his reactor group grew from eleven at the beginning of 1946 to seventy-six by the end of the year. That June, a special building was erected at the laboratory to house the reactor, and on Christmas Day it produced the first controlled nuclear chain reaction in the Soviet Union.12
Uranium enrichment required expeditions into Soviet Central Asia and mining activities that would employ a hundred thousand miners and other workers by the end of the decade. But it was the defeated enemy that provided the largest and most immediate source of ore, the result of the Germans’ tapping of uranium deposits in central Europe, particularly in Czechoslovakia. By the end of 1945, the Soviets had collected a hundred tons of uranium oxide stored in Germany, the first substantial amount acquired by the Soviet project.13
Enrichment of the uranium was entrusted to two secret sites. One, the home for an electromagnetic separation facility, was located in the Urals, about 100 miles north of Sverdlovsk and 825 miles southeast of Moscow. Consistent with Soviet practice of giving classified facilities the name of a nearby city and a post office box number, it was designated Sverdlovsk-45. Construction of the second site, consisting of a gaseous diffusion plant and satellite town, began in January 1946, near Neviansk, about 30 miles northwest of Sverdlovsk. It was assigned the code name Sverdlovsk-44.14
Chelyabinsk-40, about ten miles east of Kyshtym, fifty miles north of Chelyabinsk (itself about 115 miles south of Sverdlovsk), was the home of a plutonium production reactor (Plant A), a separation facility (Plant B), and a metallurgical plant (Plant V) to purify the plutonium and convert it into metal for use in a bomb. Construction began in 1947, using about seventy thousand labor camp prisoners. Kurchatov arrived there in the fall of 1947, along with the frigid weather, to supervise the effort, living in a railroad car next to the construction site. The reactor was built underground, in a concrete shaft, to protect it from aerial attack. After eighteen months of effort it became fully operational on June 22, 1948. The site’s location placed it close to railways and roads, two lakes that could supply huge quantities of water needed for the reactor, and the Chelyabinsk Electrode Plant, the main supplier of purified graphite. Plant B started operations on December 22, 1948, and began to produce plutonium in February 1949.15
Most secret of all was the installation established at Sarov, the site of a defunct monastery, which the Soviet government had used to house war orphans in the 1920s and prisoners in the 1930s. Located about 250 miles southeast of Moscow and about 40 miles south of Arzamas, the new secret city, isolated and surrounded by wooded lands, was designated Arzamas-16 (and was also known, at various times, as the Volga Office, Installation No. 558, Kremlev, Moscow Center 300, and Arzamas-75). During the war it had been home to a plant that turned out artillery shells. In the atomic age Sarov housed a far more lethal enterprise, Design Bureau-11 (KB-11), responsible for designing Soviet atomic bombs. KB-11’s first scientific director was Yuli Khariton, who had helped select the site. Construction of the bureau began in 1946, and physicists and other scientists began arriving the following year. Secrecy was so great that the city of Sarov soon disappeared from Soviet maps, being cut off from the rest of the world by a barbed-wire fence and guards that patrolled a one-hundred-square-mile zone. The scientists were “prisoners themselves, even if their cage was gilded,” observed author Richard Rhodes.16
German scientists who had been persuaded or coerced to join the Soviet bomb program augmented the work of Soviet physicists and institutes. Manfred von Ardenne, under whose auspices Fritz Houtermans had produced his groundbreaking work on plutonium, arrived in the Soviet Union on May 22, 1945, to lead an institute staffed by German scientists. Located at Sinop, near Sukhumi in Georgia, the organization was designated “Institut A,” just as von Ardenne’s German institute had been named. His Soviet-sponsored group investigated techniques (including electromagnetic separation) for enriching uranium. Starting with a staff of about twenty in 1945, the number of Germans working at Institut A would grow to about three hundred by the late 1940s. Among von Ardenne’s key scientists was Peter Adolf Thiessen, former director of the Kaiser-Wilhelm Institute for Physical Chemistry.17
A second institute, also near Sukhumi, at Agudzheri, was designated “Institut G,” and headed by Gustav Ludwig Hertz, the winner of the Nobel Prize for Physics in 1925 for work that played an important part in the development of quantum theory. As chief of the Siemens-Halske Laboratories during the war, he had developed a gaseous diffusion process for isotope separation, one of several areas Hertz’s institute was assigned to investigate.18
Other German scientists were assigned to other Soviet institutes. In 1946 chemist Max Vollmer was sent to work at Scientific Research Institute 9 (NII-9) in Moscow, where he headed a design bureau responsible for developing a method for producing heavy water, a project that failed to produce any benefits. In 1948, Vollmer and his associates were transferred and given a new focus, the extraction of plutonium from fission products. Nikolaus Riehl, who had been the head of scientific research at the Auer Company, wound up working on uranium purification at Elektrostal, about forty-five miles east of Moscow. After a stint at Institut A, Max Steenbeck, who had been a Siemens research scientist, worked on uranium enrichment at Laboratory 2 during 1947 and 1948.19
Construction of a test site began in 1947, in the vicinity Semipalatinsk, in the Kazakhstan desert—“an arid, partly hilly steppe with a few derelict dried-up wells and salt lakes.” Headquarters for the military unit responsible for test preparations was established on the shore of the Irtysh River, about forty miles northeast of the testing ground and approximately seventy-five miles from Semipalatinsk. Originally given the designations Mountain Seismic Station and Object 905, it received new cover names in 1948—Training Proving Ground No. 2 of the Defense Ministry, and the Semipalatinsk Experimental Proving Ground.20
In May 1949, Kurchatov and his colleagues began final preparations for the test, but were temporarily delayed when the test tower started to tilt dramatically owing to a shift in its concrete foundation. They considered detonating the bomb at ground level, but decided to erect another tower, delaying the test by two months. Finally, on August 29, 1949, Kurchatov was ready to test the first Soviet atomic bomb, a plutonium bomb designated RDS (Reaktivniyi dvigatel Stalina—Stalin’s Rocket Engine)-1. RDS-1 was based on the U.S. design for a plutonium implosion weapon, from information provided by Klaus Fuchs. The test had a code name: Pervaya Molniya (First Lightning).21 But the United States had no idea that lightning was about to strike.
WHILE U.S. INTELLIGENCE AGENCIES would provide no advance warning of the test, it was not for a lack of trying. Even during World War II, despite the rosy perception of the Soviet Union shared by many in Franklin Roosevelt’s administration, America’s ostensible ally was also an intelligence target. The Venona project—the interception of Soviet diplomatic traffic and the sometimes successful effort to read that traffic—started during the war years, and would provide critical information about Soviet espionage, including atomic espionage, during the 1940s.22
Not surprisingly, with the defeat of the Axis enemies, and as relations between the United States and the USSR deteriorated, the Soviet state became the primary focus of the American intelligence effort. In addition, one of the war’s lessons, freely available to all nations, was that an atomic bomb was not just a possibility, but a capability that could be attained by countries with sufficient expertise and resources. The United States would be concerned in the decades that followed with what other nations were doing, if anything, to acquire an atomic capability. In 1946, the primary concern was the Soviet Union.23
In 1946, the resources that the U.S. government had at its disposal to investigate Soviet progress in the atomic energy field were, in comparison to those that would become available in succeeding decades, limited. It had two primary means of collection: human intelligence and communications intelligence. After President Harry Truman’s dissolution of the OSS in October 1945, the Strategic Services Unit (SSU) was established within the War Department. It absorbed the OSS secret intelligence and counterintelligence branches, along with some of their personnel—including Moe Berg. Communications intelligence remained the responsibility of the army and navy (and also became a responsibility, after its creation in 1947, of the air force).24
Throughout 1946 the SSU sent Leslie Groves reports about foreign developments in the atomic energy field. On the next to last day in January, Lt. Col. Selby M. Skinner, the SSU’s liaison officer, reported that “a very good source” had recently told the SSU of “a secret Czech-Russian Treaty by the terms of which . . . the uranium production in Jachymov [Joachimsthal] goes to Russia.” While the SSU held the source in high regard, it still credited the reliability of the information as no more than moderate.25
That same day the SSU also passed on some information that had been received from Berg. The former baseball player reported that Peter Kapitza had invited Neils Bohr to visit Russia, but Bohr “will not himself go to Russia.” Based on his conversation with Lise Meitner, Berg concluded that she would not accept any offer from the Russians, and passed on her belief that her friend Gustav Hertz “most likely went to Moscow against his desires.” She also asserted her certainty that there would be no collaboration between the Russians and the Danes, information Berg believed she obtained from Bohr.26
By February, an SSU agent in the eastern zone of Germany provided information on where Hertz and other German scientists could be found. Von Ardenne’s group was residing in one of the small communities between Anaklia and Poti on the east shore of the Black Sea. Another agent reported that Hertz, Thiessen, and Vollmer were living on another stretch of the Black Sea coast, between Sukhumi and Poti. The agent also informed his SSU contacts that since their housing and laboratories were still under construction, Hertz and his colleagues had not done any work as of early November 1945.27
On March 5 the SSU conveyed information from a “reliable” source that there were contradictory reports about whether there was any mining activity going on at Joachimsthal, and Czech officials were refusing to discuss the mines. The source doubted that machinery at the mine could have been quickly restored to operational status or that the “great number of rail cars” needed to ship enough ore to get even meager returns were available. In addition, the source had observed no activity pointing toward an investment of much-needed capital for the mine. A March 15 report conveyed claims that a mining engineer had made to the same source—that the mining area was not occupied by the Russians, that the mines were idle, and that the laboratories were “absolutely idle.”28
Lt. Col. Edgar P. Dean, a member of Groves’s staff based at the American embassy in London, was not uncritical of SSU reports. In commenting on an earlier one, he characterized an SSU comment as “pure imagination,” while dismissing another paragraph in the same report as revealing “ignorance of facts and only conjecture.” But Dean was impressed by the March 5 report, describing it as “the best single report to emerge from the welter of contradictions [in] the last five months.” However, an apparently knowledgeable official, whose exact identity is unknown owing to the illegibility of his signature and absence of a letterhead (although the “Top Secret” marking survived), wrote to senior British atomic intelligence official Eric Welsh that while he agreed with the first two paragraphs of the report, the claims concerning the machinery, the lack of a suitable number of railcars, and the need for new capital “appear to me to be complete nonsense to anybody who knows the facts.”29
Sometime in May, Lt. Col. Peer de Silva of the SSU counterintelligence (X-2) branch sent the unit’s headquarters a Ramona report—Ramona having replaced Azusa as the code word indicating atomic intelligence—on Peter Kapitza. The information obtained, de Silva noted, was of “doubtful authenticity.” It claimed that the Soviet government had established laboratories for Kapitza and “allows him unlimited credit at the Soviet State Bank.” The SSU source also claimed that Kapitza was head of the “atomic bomb research committee,” a position actually held by Beria. De Silva’s characterization of the information in the report did not prevent the intelligence community from believing, at first, that Kapitza was the head of the atomic bomb effort.30
June brought two more SSU reports on possible Soviet exploitation of scientists and resources. One concerned the physics and chemistry institutes in Vienna, whose activities had been investigated by Moe Berg. It noted that the top two officials of the Radium Institute had been flown to Moscow for questioning and returned to Vienna, after turning down jobs in the Soviet Union. The director of the Radium Institute was, however, providing instruction in nuclear physics to Soviets in Vienna. A second letter informed its readers that a Soviet general had interviewed a Manchuria-based geologist, inquired about the presence of uranium mines in Manchuria, and was told of ones that had been discovered. He proceeded to quiz the geologist on the quality of the minerals, the tonnage capacity of the mine, and how much had been mined and where the product was taken.31
That the Manhattan Engineer District was still very interested in Soviet attempts to mine uranium ore was evident by a report completed in early December 1946. “Russian Mining Operations in the German-Czech Border Region” was written by intelligence analyst Henry S. Lowenhaupt, who had obtained a doctorate in chemistry from Yale in 1943. During his time at Yale he had worked part-time on uranium enrichment by chemical methods. After basic training at Oak Ridge, he was assigned to work for Groves in Washington, and in 1945 began to focus on foreign nuclear-related activities. In late 1946, now a civilian, Lowenhaupt was still at the beginning of a long and distinguished career in intelligence.32
His nine-page, single-spaced report covered nine different sites and, as he acknowledged in the opening paragraph, was a compilation of “probably reliable” to “possibly reliable” intelligence because “not one single absolutely reliable informant has submitted a report on any area mentioned.” The report provided no overall assessment of Russian mining activity, although it did note that, with the exception of Joachimsthal, which been turned over to the Czechs under a secret agreement, all of the uranium mines were under direct Soviet operational and security control.33
A FEW MONTHS after Lowenhaupt completed his report, he became an employee of the Central Intelligence Group (CIG), although his job remained the same. Established by President Truman on January 22, 1946, the CIG was given the mission of coordinating the intelligence reports and estimates of the government’s other civilian and military intelligence units, employing personnel from those other organizations. In July, the CIG established the Office of Special Operations to conduct espionage and counterintelligence operations, and in October that office assumed the mission of the SSU, with a limited number of SSU personnel joining the new office.34
A little over six months after the birth of the CIG, on August 1, legislation established the Atomic Energy Commission (AEC) in place of the MED. Lt. Gen. Hoyt Vandenberg, the CIG’s director, sought to preempt any AEC takeover of the atomic intelligence mission, suggesting that the personnel and records of Groves’s foreign intelligence section be transferred to his central intelligence organization. Such a transfer would have to be approved by the National Intelligence Authority (NIA)—the four-person committee, whose members included the secretaries of war, navy, and state and Truman’s military adviser, that had been established by the president to supervise the CIG.35
By mid-August, Vandenberg had transformed his proposal into a draft NIA directive on the coordination of atomic intelligence activities, which was discussed at an NIA meeting on August 22, after acting secretary of state Dean Acheson blocked its approval, unsure of whether the AEC would continue to have access to the information needed in its search for uranium ore. While there was strong support for the proposal, Truman, who was away from the capital, wanted to consider the issue further when he returned. Additional delay followed owing to opposition to Truman’s choice to head the AEC, David Lilienthal, and the president’s desire to wait until all members of the AEC had been appointed before considering the intelligence issue.36
Groves’s doubts that Lilienthal and his staff could be trusted to handle his organization’s intelligence files responsibly was one reason why he supported the idea of turning his intelligence section’s personnel and files over to the CIG. In a November 21, 1946, memo to the AEC, Groves argued that it was “vital to the security of the United States that foreign intelligence in the field of atomic energy be maintained and strengthened.” Since the CIG was responsible for the coordination and direction of all foreign intelligence activities, and the best nucleus “upon which to build” its atomic energy intelligence component was the MED Foreign Intelligence Section, it followed that the CIG should absorb the section. The AEC, as Groves envisioned the arrangement, would be the recipient of the CIG’s collection and analysis of information on ore deposits and discoveries, mining activities, and foreign scientific developments that the AEC needed to know about to perform its mission.37
By the time the NIA convened for its ninth meeting, on February 12, 1947, the issue was ready to be resolved. The meeting was attended by George C. Marshall, the recently approved secretary of state, Robert Patterson and James Forrestal, the secretaries of war and navy, Fleet Admiral William D. Leahy, Truman’s representative, Vandenberg, and a number of observers. It was agreed that the AEC would be able to examine the files to be transferred to the CIG and retain those on uranium deposits. With that matter settled, the NIA approved the transfer of the MED’s intelligence files to the CIG. By February 18, Henry Lowenhaupt was officially an employee of the CIG, and before the end of March the Foreign Intelligence Section had become the Nuclear Energy Group, Scientific Branch, Office of Reports and Estimates, Central Intelligence Group. Its primary responsibility was to prepare “estimates of the nuclear energy capabilities and intentions of foreign nations.”38
The transfer to the CIG would only be the beginning of several years of organizational turmoil for Lowenhaupt and his colleagues. On July 26, 1947, Truman signed legislation transforming the CIG into the Central Intelligence Agency (CIA), which was no longer dependent on other agencies for its personnel or funding. By December, the AEC had established its own Intelligence Division, an action that had been urged earlier that year in a report on atomic energy intelligence by Sidney Souers, Vandenberg’s predecessor as director of central intelligence. Then, on March 5, 1948, less than a year after the nuclear energy group had been established in the Office of Reports and Estimates (ORE), the group was transferred, without any change of mission, to the Office of Special Operations and became its Nuclear Energy Branch. Finally, on the last day of 1948, in response to an outside review prepared by Allen Dulles and two colleagues that criticized the agency’s scientific intelligence effort, director of central intelligence Roscoe Hillenkoetter reattached the nuclear energy unit to the scientific branch of the reports and estimates office and transformed the branch into the Office of Scientific Intelligence (OSI), which would be home to the agency’s nuclear intelligence analysts for decades to come.39
The creation of a nuclear energy group within CIG/CIA was one of three major developments in the nuclear intelligence area in the late 1940s. In December 1947, Maj. Gen. Albert F. Hegenberger returned to the United States from his assignment in Japan, where he had served as commanding general of the First Air Division. On December 5 he was assigned to the Special Weapons Group, an organization that reported to the air force’s deputy chief of staff for materiel and interacted with the Armed Forces Special Weapons Project (established in light of the AEC’s supplanting of the MED, and headed by Groves) and the AEC on matters concerning atomic bombs. Nine days later, Maj. Gen. William Kepner, the Special Weapons Group commander, established a new section within his group, designated Section One, and named Hegenberger commander. By the end of July 1948, Hegenberger’s unit, AFMSW-1, was transferred to the office of the deputy chief of staff for operations, and thus became AFOAT-1: Air Force Deputy Chief of Staff for Operations, ATomic Energy Office, Section 1.40 AFOAT-1 was to play a key role in tracking the nuclear activities of foreign nations, employing different methods than the CIA and other intelligence agencies.
Late 1947 also witnessed the creation of an interagency committee that would assume a significant role in the analysis of nuclear intelligence. Despite his initial reservations, Rear Adm. Thomas Inglis, the chief of naval intelligence, along with Hillenkoetter and the army and air force intelligence chiefs, signed a memorandum on December 31, establishing the Joint Nuclear Energy Intelligence Committee (JNEIC). The committee would eventually meet on an almost weekly basis and collaborate with the CIA’s Nuclear Energy Branch in preparing studies of foreign nuclear programs.41
THROUGH JULY 1949, the analysts at the CIG/CIA, JNEIC, the AEC’s Intelligence Division, the Joint Chiefs of Staff (JCS) Joint Intelligence Committee, and the military intelligence services had been the beneficiaries of whatever intelligence could be obtained by the United States and Britain concerning the Soviet nuclear effort.
A March 1947 letter, written by Nikolaus Riehl’s secretary, was intercepted and confirmed that Riehl was at Elektrostal near Moscow, along with others who had worked with him at the Auer Company. Early 1947 also saw the defections of four German atomic scientists who had traveled to the Soviet Union for job interviews and had been returned to East Germany. One, Dr. Adolf Krebs, reported that the Hertz group was working on isotope separation problems at Sukhumi while von Ardenne’s institute was located nearby. He also told his debriefers that Max Vollmer was working on heavy-water production (which came as a surprise), with Riehl and his group producing uranium metal. In addition, he revealed that the former director of the Joachimsthal mine was heading a group near Tashkent, in Central Asia, searching for uranium.42
U.S. knowledge of uranium mining in Czechoslovakia benefitted from both British and CIA collection activities. In 1946, Britain had discovered that one ten-ton freight car of uranium ore was being shipped from Joachimsthal to Elektrostal every ten days. In addition, the Soviets required the former Bitterfeld plant of I. G. Farben to turn out thirty tons of highly pure metallic calcium each month, enough for the manufacture of sixty tons of uranium metal. Sources within the Soviet program furnished specifications on the amount of impurities permitted in the calcium; that information established beyond a doubt that it was for atomic use. CIA clandestine collection efforts produced a bill of lading for three freight-car loads of calcium from Bitterfeld to Post Box 3, Elektrostal, which proved that there was a uranium factory at Elektrostal producing the metal in quantity and employing methods at least partially developed by Riehl. It also led to the conclusion that the Soviet program included a functioning or planned reactor to make plutonium for nuclear weapons, since the metal being produced was not needed to enrich uranium but was required for the production of plutonium in a reactor.43
In 1948, British interrogation of a former German prisoner of war revealed the existence of the plutonium facility (Chelyabinsk-40) near Kyshtym, one of a number of POW reports on Kyshtym. A copy of the report was passed to the U.S. naval attaché in London and to a representative of U.S. naval intelligence in Germany. Reports from U.S. sources in Europe noted that some leading Soviet physicists and chemists had been assigned to the facility. That same year, a POW told his American interrogators of the Soviet gaseous diffusion effort, and that it was in a primitive stage.44
During 1948–1949, U.S. intelligence efforts also yielded new information on mining in Czechoslovakia. The new data, provided by a single source who was considered reliable, indicated that the Soviets were extracting between five and eight times as much uranium as Britain had thought likely, and between four and six times as much as British experts believed possible. Further intelligence, from intercepted letters and refugee reports, confirmed the source’s claims.45
Beyond reports from spies, refugees, and former POWs, communications intelligence was obtained by the military communications intelligence (COMINT) agencies. By August 1949, those agencies consisted of the Army Security Agency, the Naval Security Group Command, and the Air Force Security Service. There was also the Armed Forces Security Agency, established that May to coordinate and supervise the military-service efforts.46
In the latter half of April, central intelligence chief Hillenkoetter, in a memo to the executive secretary of the National Security Council, urged that the communications intelligence effort against the Soviet atomic energy target be stepped up (along with an increased use of other collection methods). Secretary of defense Louis Johnson directed the JCS to review the issue. In June, he was informed by the JCS and the U.S. Communications Intelligence Board (the interagency committee that supervised the communications intelligence effort) that “for many months the production of information regarding the atomic energy program of the USSR has been accorded the highest priority in the COMINT field.” He was also advised that “no more effort can be diverted from other highly important problems without serious detriment to those problems.” According to one account, communications intelligence had produced “some useful intelligence about Soviet work in the field of atomic energy.”47
Former air force intelligence officer Spurgeon Keeny recalls that there was “a lot” of communications intelligence on Soviet atomic energy activities. Keeny had been drafted in 1948, and received a commission in the air force. He finished college during the war, received his master’s degree in physics from Columbia in 1946, and was a member of the first class of the Russian institute at Columbia. His background made him a logical candidate for the service’s Directorate of Intelligence, located in the Pentagon. He recalls that a number of factors contributed to the availability of communications intelligence—the geographical breadth of the Soviet Union, which resulted in an absence of landlines and the widespread use of radiotelephones, as well as “lots of plaintext” transmissions. The intercepted communications, along with the assorted varieties of human intelligence, and the examination of Soviet scientific literature, meant that early on in the Soviet program, the United States “knew [the] location of most main activities.” Kyshtym, Keeny recalls, was identified even before the British provided the United States with that information.48
Intelligence from human and technical sources provided valuable information on where Soviet and German scientists were working on an atomic bomb, and what they were doing at various sites. But it did not answer what was, at the time, the burning question: when would the Soviets have an atomic bomb? Even Lavrenti Beria did not know for sure, although he had far more information available to him than U.S. intelligence analysts. That extra information would surely have helped American analysts in their effort to provide a reasonable estimate of an initial Soviet nuclear capability. The lack of complete information was reflected in American estimates in two ways: the differences between intelligence agencies as to when the Soviets were most likely to have the bomb, and the range of years given in individual estimates as to when the Soviets might end the U.S. nuclear monopoly.
In 1946, the CIG, noting that “our real information . . . is relatively meager,” judged that the Soviets would first test a bomb sometime between 1950 and 1953. That same year, the air intelligence element of the Air Staff (at the time, still part of the U.S. Army) suggested that the Soviets might detonate a bomb toward the end of 1949. In July 1947, an analysis by the three major service intelligence organizations produced some agreement—including the observations that some details of the Hanford plutonium production plant may have been provided to the Soviet Union via espionage, that the Soviets did not yet have a working reactor, that the Soviet Union lacked skilled engineering and experienced technical personnel, and that uranium ores available from many areas within the Soviet Union or Soviet-controlled territory were of low uranium content. There was disagreement, however, in a key area. The intelligence chiefs of the army and navy believed that the Soviet Union “could not have atomic weapons now,” could possibly have them in 1950, and would “most probably” have them during 1952. The assistant chief of the Air Staff for intelligence concluded that the Soviet Union might already have an atomic weapon and would most probably have one between 1949 and 1952.49
In 1948, the JCS’s Joint Intelligence Committee estimated mid-1950 as “the earliest date by which the Soviets [might explode] their first bomb,” and mid-1953 as “the probable date.” That July, the Estimate of the Status of the Russian Atomic Energy Project, provided to President Truman by Hillenkoetter, echoed the committee’s finding. It confessed that “it continues to be impossible to determine the exact status of or to determine the date scheduled by the Soviets for the completion of their first atomic bomb,” but agreed that “on the basis of the information in our possession, it is estimated that the earliest date by which it is remotely possible that the USSR may have completed its first atomic bomb is mid-1950, but the most probable date is believed to be mid-1953.”50
By early 1949 the air force had concluded that 1950 was the earliest date. In March, Willard Machle, the CIA’s director of scientific intelligence, informed Hillenkoetter that the JNEIC “has sufficient data to make the following estimate”: “mid-1950 is the earliest possible date for Soviets to complete their first atomic bomb, and mid-1953 is the most probable date for completion.” Machle noted that the estimate was based on three conclusions: that the Soviets did not begin development of an atomic bomb until late 1945, that they were attempting to build a plutonium bomb, and that they had sufficient uranium for the operation of one plutonium reactor.51
He went on to explain that the mid-1950 date was based on the U.S. British, and Canadian experience with atomic energy, while the mid-1953 date was the result of comparing Soviet and Western industrial performance in other fields of similar size and complexity. He also noted that “during the past years information has been received which furnishes a picture of the organization of the Soviet atomic energy program and certain localities involved.” He cautioned, however, that the “available information as well as uncertainties inherent in industrial development make it impossible to state with greater accuracy the dates cited above.”52
MUCH, MAYBE ALL, of the uncertainty surrounding the timing of the first Soviet bomb test would have been eliminated if the United States (or Britain) had a high-level spy in the Kremlin or KB-11, or if it had been possible to eavesdrop on conversations between Khariton and Kurchatov or Kurchatov and Beria. Instead, the Americans had to settle for the hope that any Soviet atomic detonation would be detected shortly after the fact, and that it would be possible to acquire intelligence on the nature of the explosion, including the type of bomb (uranium or plutonium) and its power.
That hope centered on an interim system for the long-range detection of atomic explosions that had been established after World War II. Rather than depending on the word of a spy, an intercepted communication, or the photograph of a mushroom cloud, the system relied on the inevitable by-products of an atomic detonation to announce its occurrence, by-products that could be detected by having the right equipment in the right place at the right time.
In 1945 and 1946, believing it unlikely that the Soviet Union would develop a bomb but not test it, Leslie Groves, then still head of the Manhattan Project, and Gen. Curtis LeMay, the Army Air Force’s research chief, initiated separate projects to determine if an atomic detonation could be detected from outside of Soviet territory. They were not the only early advocates of investigating the feasibility of long-range detection. Officers from each of the services, including Edwin Siebert, the head of the army’s G-2, also suggested the need for a detection system.53
The possibility of detection emerged from the data produced by the July 1945 Trinity test. Two Met Lab scientists, Anthony Turkevitch and John Magee, suggested, with the Krakatoa volcanic explosion of 1883 in mind, that debris from an atomic explosion might be blown around the world, debris that would carry the radioactive fission products of the detonation. To test their hypothesis, a B-29 was modified to carry an air scoop on top of the plane’s fuselage. Connected to the scoop was a tube that led to a perforated metal cylinder lined with soft tissue paper, similar to the paper used in air filters at the Trinity test site.54
In the aftermath of the Hiroshima blast, five flights were flown, at altitudes between 15,000 and 30,000 feet. Two flights originated from Wendover Field in western Utah, a site designated W-47. The first, on August 10, was completed when it landed in Bakersfield, California, while the other went on to Seattle after landing in Bakersfield. Another two flights departed from Seattle to Alaska and returned, and the fifth, on August 15, arrived at W-47 from Seattle. After each flight the paper was removed and checked for radioactivity.55
An analysis of the data completed that fall led to the conclusion that radioactive dust had been detected and that it “seems reasonable that the activity observed is due to the fission products from Hiroshima”. This conclusion may have been drawn without proper consideration of the greater volume of dust that resulted from the Trinity test as well as the flight paths of the B-29s, which took them over the Hanford reactor site. In any case, the analysis concluded that the type of air filter employed “would seem to be a practical means of detecting an atomic bomb explosion almost anywhere with proper meteorological conditions.”56
At about the same time, the Army Air Force began exploring another potential means of long-distance detection of atomic bomb tests, an effort designated Project Mogul. It was inspired by geophysicist W. Maurice Ewing’s wartime discovery that at a depth of four thousand feet in the ocean there was a layer of water through which sound waves could travel unlimited distances without contact with the surface or ocean bottom. In October 1945, Ewing suggested to Gen. Carl Spaatz, the Army Air Force’s commander, that a similar channel might exist in the atmosphere.57
That observation led Col. Roscoe C. Wilson, Spaatz’s deputy chief of staff for research and development, to initiate a program to explore the feasibility of monitoring such a sound channel for signs of a nuclear detonation thousands of miles away. Since it was believed that the channel was located at approximately 45,000 feet, and B-29s were only capable of flying at little more than 30,000 feet, it would be necessary to place the sonic detectors on balloons that could float at a constant altitude. Such balloons did not exist at the time, and one early part of Mogul included research on how to make them a reality.58
Key factors in developing long-range detection methods were the atmospheric tests the United States was conducting to improve its own nuclear arsenal and to evaluate the vulnerability of its forces to atomic attack. Operation Crossroads, conducted on Bikini atoll in the Pacific, was one instance. On July 1, 1946, a flotilla of thirty-eight obsolete U.S. and Japanese ships, ranging from battleships to submarines, was the target of a 23-kiloton bomb detonated 520 feet above them in an attempt to determine just how vulnerable such ships were. A second bomb would be detonated underwater on July 25. Another element of Crossroads, consistent with Groves’s interest in developing monitoring techniques, was to evaluate possible ground- and air-based detection methods.59
Microbarographs located on Pacific islands recorded sonic data, while Geiger counters on those islands measured radioactivity at ground level. Air operations included drones flown into the atomic cloud to gather dust and air samples, and aircraft capable of measuring airborne radioactivity tracking the cloud out to about 500 miles. B-29s, carrying filters capable of collecting the minute dust particles that a detonation would produce, were deployed to sites in the Pacific (Guam, Okinawa, and Hawaii), on the West Coast (Spokane), and elsewhere (Tucson, Tampa, and Panama), ranging 1,600 to 8,000 miles from ground zero. Each day, the aircraft patrolled at 30,000 feet and the filters were examined for signs of the blast.60
The results of the Crossroads experiments indicated that much work needed to be done. While seismographs in California detected the underwater July 25 explosion, they failed to record the airburst of July 1. In addition, seismographs were not capable of distinguishing between a low-yield atomic explosion and a large-scale conventional one. In a September 18 memo to Groves, Maj. Philip G. Krueger concluded that “it is possible by monitoring the air currents at various points around the world to determine if an atomic bomb has been detonated in the air.” Detailed analysis of wind conditions might make it possible to determine the direction to the blast, and, “by additional judicious reasoning,” approximately when and where it occurred. However, Krueger noted two limitations: very high counts of radioactivity were required to conclusively establish that a bomb had been detonated, and positive results could be most reasonably expected when the blast occurred at a distance of 2,000 miles or less. Thus, at the time, none of the methods tried could promise an unambiguous means of detecting a Soviet test that took place deep within Soviet territory. Col. Lyle E. Seeman, the associate director at Los Alamos, noted that “no instruments exist at present to insure success.”61
Long-range detection was also of interest to General Vandenberg, director of the CIG. About the time Krueger completed his memo, Vandenberg sent one of his own to Groves, requesting information about the performance of experimental long-range detection techniques and seeking recommendations on what could be done to develop a reliable detection system. When Groves replied several months later, he told Vandenberg that the instruments and procedures for long-range detection required further development.62
The following spring, as research on long-range detection continued in secret, another prominent official suggested that such programs should be pursued. This time it was a member of the AEC, Commissioner Lewis L. Strauss—a lifelong Republican who owed his position, in part, to Truman’s need to appear nonpartisan in his appointments to the new body. Strauss had joined the naval reserve in 1926 as a lieutenant commander, and spent fifteen years as a reserve officer attached to the Office of Naval Intelligence (ONI). When war came, he was called to active duty, but with the Bureau of Ordnance. He left the navy, at the end of the war, as a rear admiral. When he joined the AEC in 1947, he gave up a position that was far more lucrative than any government job, a partnership in the Wall Street firm of Kuhn, Loeb, and Company.63
In an April 11, 1947, one-paragraph memo to his fellow commissioners, who also were unaware of what was being done elsewhere in the government to develop a long-range detection program, Strauss wrote that “it would be interesting to know whether the intelligence arrangements of the Manhattan District made any provision in the past for the continuous monitoring of radioactivity in the upper atmosphere. This would be perhaps the only means that we would have for discovering that a test of an atomic weapon has been made by any other nation.” He went on to suggest that if the CIG had no such system in place, the commissioners might want to recommend that it develop one and, in the event of the CIG’s refusal to do so, that the AEC might consider taking action on its own.64
Strauss followed up his memo in meetings with Vandenberg and Colonel Seeman, but was kept in the dark about the status of the effort. He came away dissatisfied and approached army secretary Kenneth C. Royall, army chief of staff Dwight Eisenhower, and secretary of the navy James Forrestal—in Forrestal’s case to determine if his service could fly monitoring missions in the Arctic and off the Asian mainland. While the navy had a very limited number of planes that could perform such a mission, the Army Air Force’s Air Weather Service was already flying WB-29s in the areas suggested by Strauss.65
A big step toward establishing a full-scale detection program came on May 21, when representatives from the army, navy, AEC, CIG, and the Joint Research and Development Board met as the Long-Range Detection Committee, organized in response to a March memo from Vandenberg. By the time of the meeting, Vandenberg had become the air force’s chief of staff, but the initiative continued under his successor, Roscoe Hillenkoetter. The committee identified three basic objectives for a detection system: determining the time and place of all large explosions on earth, obtaining samples of the explosive products from water or air or both, and establishing the nature of the explosions by chemical and radiological analysis of the samples collected. Techniques that were considered worthy of exploration included monitoring sonic and seismic activity at terrestrial stations, detecting sounds via an underwater system, and collecting samples using ships and aircraft equipped with containers and filters. The committee also concluded that air-sampling operations to provide data on the existing levels of radioactivity could be started without delay. In addition, the group suggested that direction of the project should be the responsibility of the Army Air Force.66
The next year was filled with the usual bureaucratic maneuvers involved in establishing new activities—exchanges of memos, committee meetings, and disputes over the division of responsibilities. Groves claimed that his Special Weapons Project was most capable of analyzing any data obtained by a monitoring network. AEC Chairman Lilienthal responded to a June 30 memo by Hillenkoetter, which estimated that it would take two years to have a complete monitoring network in place, with a memo of his own. He told Hillenkoetter that the AEC regarded it as essential that “a working arrangement, even though less than ‘complete,’ for the detection of atomic explosions in other parts of the world be established without much delay.” In contrast, in January 1948, James Conant, chairman of the Research and Development Board’s Committee on Atomic Energy, informed board chairman Vannevar Bush that his committee had “grave doubts as to whether [Hillenkoetter’s] optimistic view [in his June 30 letter] is justified.”67
Some of the difference in viewpoints as to when the United States could and should have a viable long-range detection program was due to varying degrees of access to information, and different assumptions. The belief that detection capabilities were more advanced than they actually were and a fear that a Soviet bomb might be imminent led some, such as Lilienthal, Strauss, and Le May, to press for quick action. Groves and others knew that more work had to be done before any form of detection could be reliable, and they mistakenly believed, because of their knowledge of another highly secret program, that a Soviet bomb was not imminent.68
Some of the anxiety of those pushing for a detection capability was diminished when the issue of assigning responsibility for the monitoring effort was settled. After meetings between senior officials, it was agreed that the Army Air Force was best equipped to handle the mission. On September 16, following the instructions of the secretary of war, Eisenhower sent a memo to Spaatz, instructing him to assume “over-all responsibility for detecting atomic explosions anywhere in the world.”69 That order would result in the formation of AFMSW-1 and its successor, AFOAT-1. What remained was to develop adequate technical detection capabilities and create a network based on those capabilities.
Work had continued on some potential detection capabilities while the issue of an institutional home for the long-range monitoring program was being debated. In November 1946, New York University was awarded a contract for the development of balloons that could loiter for as long as forty-eight hours at a predetermined altitude between 33,000 and 66,000 feet while carrying sonic detection equipment. The university’s director of research, Capt. Athelstan Spilhaus, a geophysicist, had served during the war under Col. Marcellus Duffy, now the officer in charge of Project Mogul.70
Spilhaus assembled the Constant Level Balloon Group, which included his wartime assistant, Charles Moore. Between June 4 and July 7, 1947, the group launched eight trains or clusters of polyethylene balloons from the Army Air Force base in Alamogordo. Each balloon carried a low-frequency microphone, of which the capability to pick up distant, preset explosions was tested. Some balloon groups operated at maximum altitudes of over 48,000 feet; others, in the range of 15,000 to 19,000 feet. Further development followed, and by the end of the year balloons meeting Mogul requirements were available.71
Another opportunity to test assorted potential long-range detection techniques came in April and May 1948, when three bombs (X-Ray, Yoke, and Zebra) were detonated on Eniwetok. The tests were designated Operation Sandstone, while the Special Weapons Group’s monitoring effort was code-named Operation Fitzwilliam.72
The arrangements for Fitzwilliam were in large part the work of Dr. Ellis A. Johnson, the scientific director for AFMSW-1. A graduate of MIT, he had spent a few years there as an instructor before moving on to the Carnegie Institution’s department of terrestrial magnetism in 1935. On loan to the Naval Ordnance Laboratory to work on magnetic mines, he was at Pearl Harbor on December 7, 1941. While there he solved the problem of American submarine torpedoes that failed to explode when they hit their Japanese targets. After the war he returned to Carnegie, but took a leave of absence when invited to join the new monitoring organization.73
The scientific program that Johnson and his colleagues developed involved testing the three primary candidates for employment in long-range detection—radiological, seismic, and sonic—while exploring the potential of other, exotic techniques.* Attempting to observe a light flash reflected off the dark side of the moon after an explosion was one of those techniques. Measuring the magnetic effects of the dynamo action in the ionosphere caused by the pressure waves from a detonation, and detecting a blast-induced “dimple” in the ionosphere were the others. The complete test program consisted of nineteen projects, carried out by eight different agencies, dispersed halfway around the world.74
The primary element of the radiological experiments were the air-sampling missions conducted by the Air Weather Service. Along with the regular flights of filter-equipped aircraft that took off from bases in Guam and elsewhere, the weather service employed eight WB-29s on special sampling missions. The aircraft, based at Kwajalein, were fitted with radiation intensity recorders as well as with a device to collect atmospheric gas samples and filters to collect airborne particles. WB-29s also flew from bases on both coasts of the United States as well as in Bermuda, the Azores, and North Africa.75
One participant in the far-eastern segment of the aerial sampling program, designated Operation Blueboy, was Arnold Ross, the chief radio operator for Flight C of the 373rd Reconnaissance Squadron, Very Long Range Weather. In a 1985 letter, Ross recalled, on the basis of the personal logbook he had kept, that
we left Lagens [in the Azores] on the 14th of May and proceeded to Wheelus Field, Tripoli, Libya. Using Wheelus as home base . . . we flew high altitude (35,000 feet) missions through Egyptian airspace, up to the Turkish border, through the Mediterranean area, and on one occassion, on 30 May we flew a 15 hour mission from Wheelus to the Cape Verde Islands. On all of these missions, the filter box was used, with filters being changed every hour on the hour. When removed from the filter box they were placed in a lead lined container, and upon completion of Operation Blueboy on 6 June 1948, the containers were returned to Washington.76
All together the Fitzwilliam air-sampling missions involved 466 sorties and 4,944 hours of time in the air. The area of coverage stretched from the polar regions in the north to the equator in the south, and from Manila in the Pacific to Tripoli in Africa.77
To test the feasibility of seismic detection, a team from the Coast and Geodetic Survey operated short-range diagnostic seismographs on the Runit, Parry, and Aniyaaii atolls in the vicinity of Eniwetok. Naval Ordnance Laboratory seismographs were installed at eight different sites in the Pacific, including on Kwajalein and Eniwetok. Both the ordnance lab and the Army Signal Corps established networks of sonic sensors. The navy detectors were located at six of the eight seismograph sites, while the signal corps network included five sites that extended from Japan to Germany (with sites in Hawaii, California, and New Jersey in between). Each army station was equipped with an array of twenty or more acoustical sensors.78
The air force’s sonic detection equipment was carried on the Project Mogul balloons. For each of the three detonations, balloons were launched from progressively more distant sites to test the feasibility of sonic detection. The launch from Kwajalein (450 miles away) was followed by launches from Guam (1,200 miles) and Hawaii (2,750 miles). Mogul balloons were also launched from bases in New Mexico and Alabama.79
Naturally, the exploratory efforts for more exotic detection methods were less extensive. Two Army Signal Corps teams, hoping to detect the optical signatures of the detonations after they bounced off the moon, set up on Guam and Eniwetok, with telescopes coupled to photoelectric detectors and cameras. The search for electromagnetic effects took place on Eniwetok and Kwajalein, where naval ordnance personnel deployed high-sensitivity magneto meters. The search for an ionospheric dimple was confined to Kwajalein, where an ionospherograph—a pulsed radiotransmitter that periodically swept the frequency band between 1 and 25 megahertz—had been installed. Back in New Mexico, some Los Alamos scientists set up photoelectric recording equipment to determine if there was a notable change in the sky’s illumination due to a nuclear test over 5,000 miles away.80
For most of the techniques tested in Fitzwilliam, the results were poor or worse, particularly with regard to distant atmospheric tests. The 49-kiloton blast of April 30, designated Yoke and the largest of the three, could not be detected by seismometers more than 500 miles from the site of the blast. Sonic detectors worked better, but their range was still too limited to detect tests in the Soviet heartland. The Yoke test was detected at 1,700 miles while the 18-kiloton blast of May 14 was detected at 1,000 miles. The data produced by the Mogul balloons was no better than that from the sonic detection devices on the ground, equipment whose operation did not involve the operational and security problems associated with balloons. As a result, the effort was abandoned.81
None of the exploratory techniques appeared to be useful. If any light ricocheted off the moon as the result of the tests, it was not detected. The magnetic experiment also came up empty, “with no indication of magnetic phenomena recorded,” according to the team leader. The search for an ionospheric dimple never got a chance after it was discovered that the ionospherograph interfered with the radio control of the drone aircraft as well as the telemetry of other experiments. And the photoelectric equipment in New Mexico gave no indication of increased illumination in the sky on the one occasion when the devices were operational—at the time of the third test.82
The good news was that airborne radiological detection showed promise. Ground-based equipment for detecting the radioactivity proved to be relatively insensitive if located more than approximately 600 miles from the blast. The problem, according to an analysis of the results, was “the small concentrations of debris” that fell back to earth more than 600 miles from the test site. The results using aircraft were quite different. A variety of radiation detectors, when carried by aircraft flying at altitudes of 25,000 to 35,000 feet, proved capable of detecting and tracking radioactive clouds of atomic debris to distances of about 2,000 miles from Eniwetok.83
While the results indicated that airborne detection devices could be used to track a radioactive cloud, they could not unequivocally establish its cause, which might be from a reactor accident or a nuclear explosion. Another approach, collecting the airborne dust created by a detonation, was also tested because it allowed the fission products to be subjected to chemical and physical analyses to establish that an atomic bomb had been tested. Here the results were particularly valuable and impressive. Samples collected over Tripoli, about 12,000 miles from the test site, were successfully subjected to radiochemical analysis. It was also discovered that debris brought back to earth by rainfall as far as 9,000 miles from the detonation site, gathered at radiological ground stations equipped with precipitation collectors, could also be analyzed to confirm an explosion and details of the device.84
While rainfall collection was far cheaper and less dangerous than airborne monitoring, it also depended on a certain amount of luck. The radioactive cloud not only had to pass over a rainwater collection station, but also had to do so at a time when nature contributed some rainfall. In contrast, launching aircraft was a matter of choice, not chance. Based on analysis of the fission products of the Sandstone tests, Ellis Johnson was able, on July 8, to tell members of the AEC that “the Air Force was confident of being able to detect by radiological means an atomic airburst.”85
Johnson and his staff envisaged creation of an interim radiological detection system based on airborne monitoring, with experimental sonic and seismic detection networks being added in the future. But failure to obtain approval from higher authority outside of the monitoring organization for research projects he considered vital, including the initial airborne network, led him to resign as technical director. It would not be until the spring of 1949 that the Joint Chiefs would formally give their blessing to the creation of an interim long-range detection system, by which time Johnson’s successor had also resigned over the multiple reviews by multiple committees that forced multiple revisions of the AFOAT-1 program.86
The process of establishing an interim network had begun well before final JCS approval. Shortly after the Sandstone tests and the detection effort concluded, Johnson had transformed the set of radiological ground stations into the network that would be part of the interim detection system, closing two Pacific stations (at Wake Island and at Henderson Field, Guadalcanal) and moving their equipment to a new station at Lagens Air Force Base in the Azores. Each of the twenty-four ground stations, located in a huge arc extending from Guam northward to Alaska and then southward to the Canal Zone, was equipped not only to detect radioactivity but also to gather airborne debris. One very simple piece of equipment was a shallow tank that collected rainfall. The interim network also included six sonic stations operated by the Army Signal Corps. Originally there were stations in Alaska, Hawaii, California, New Jersey, Germany, and the Philippines, although the network may have undergone some revision before August 1949.87
In July 1948, AFOAT-1 assigned the code name Workbag to Air Weather Service participation in the monitoring program (the entire monitoring effort was first code-named Whitesmith, and subsequently Bequeath). Four Air Weather Service reconnaissance squadrons, with about fifty-five filter-equipped WB-29s, formed the backbone of the interim detection network. The WB-29s flew from Guam, Alaska, California, and Bermuda. Collectively their efforts covered the Northern Hemisphere from the pole to the equator and from Korea to as far west as Libya, excluding only the North Atlantic region.88
Two other contributors to the atomic detonation detection capability at the beginning of August 1949 were the U.S. Navy and the United Kingdom. The navy’s effort, Project Rainbarrel, was initiated by Herbert Friedman, a Naval Research Laboratory (NRL) physicist. As a result of his work with the radiation detectors established at naval monitoring stations as part of the navy’s own detection efforts, he discovered that rainfall could carry with it the debris from an atomic detonation. Based on his suggestion, Peter King, head of the laboratory’s chemistry division, and Luther Lockhart, another NRL chemist, developed a method of separating some of the rainfall-carried debris for chemical analysis. The navy was already operating naval stations at Manilla; Honolulu; Kodiak, Alaska; and Washington, D.C.—all equipped with two devices, one that constantly recorded the level of gamma radiation while the other collected airborne radioactive material. In April 1949, the Kodiak and Washington stations were equipped with a rainfall collector—a rooflike aluminum structure 2,500 square feet in area that rested on ten-foot-high posts. Along the perimeter were runoffs that permitted water to flow into storage tanks. If there was no rain to carry the debris into the tanks, “roof scrubbing” would be conducted to collect the dry fallout.89
When informed of the Sandstone tests, the British rushed to establish an interim network of their own. After a subsequent meeting between military representatives of the United States, Canada, and the United Kingdom, during which the subject of monitoring was discussed, the British followed up by establishing radiological ground stations at airfields in Scotland, Northern Ireland, and Gibraltar, while Royal Air Force bombers at those bases were fitted with filters similar to those carried by WB-29s. By the summer of 1949, British monitoring aircraft were conducting routine missions covering the North Atlantic, flying from Gibraltar (code-named Nocturnal) and Britain (Bismuth).90
The final piece of the network were two laboratories, located in Berkeley and Boston and operated by Tracerlab, a private contractor that had been established in March 1946 to manufacture equipment for measuring radioactivity. The company would first become involved with the long-range detection program in February 1948, and would take part in the Fitzwilliam operation. Its laboratories provided the crucial radiochemical analysis of the debris collected by aircraft and ground stations.91
JUST AS LESLIE GROVES, Robert Oppenheimer, and assorted Los Alamos scientists were present at the Trinity test site in July 1945, Beria, Kurchatov, and other key figures in the Soviet program could be found at Semipalatinsk in late August 1949. One key difference though was that neither Oppenheimer nor his scientific colleagues had any reason to believe that they would be shot or wind up in a prison camp if the test failed. The same could not be said for Kurchatov, Khariton, and their associates.92
Beria, their potential executioner, had arrived at the test site during the second half of August to review preparations. On the night of August 28 and into the next morning, he, Kurchatov, Khariton, and others watched the bomb be put together. By about two o’clock in the morning, it was almost fully assembled and was wheeled out of the assembly area toward the platform where it was to be detonated. Kurchatov made his way to the command post, while Beria headed off to a cabin near the command post and slept for a few hours. The device was raised to the top of the platform, where the final assembly was completed.93
Very early that morning, Kurchatov gave the order to detonate “Stalin’s Rocket Engine-1.” One witness recalled that “on top of the tower an unbearably bright light blazed up. For a moment or so it dimmed and then with new force began to grow quickly. The white fireball engulfed the tower and the shop and, expanding rapidly, changing color, it rushed upwards. The blast wave at the base, sweeping in its path structures, stone houses, machines, rolled like a billow from the center.” Another of those present recalled that “the steel tower on which the bomb had been hoisted had disappeared together with the concrete foundation . . . in place of the tower there yawned a huge crater.” Beria responded to the successful test by embracing Kurchatov and Khariton and then kissing each on the forehead.94
After returning to his hotel, Kurchatov prepared his handwritten assessment of the test. He was able to report that the goal of a 20-kiloton blast had been achieved. For the next two weeks, analysis of the test results continued at the site of the blast. The levels of radioactivity in the air and in the soil were measured, the path of the radioactive cloud was tracked by aircraft, and cars journeyed into areas where debris had fallen to the ground to determine the extent to which the soil had been contaminated.95
WHILE THE UNITED STATES would have no opportunity to examine the results at the test site, or read Kurchatov’s report, the radioactive cloud could not be contained inside Soviet borders. By late August the airborne segment of America’s interim detection network had been operating on a routine basis for several months. The filter-equipped WB-29s of the 375th Weather Reconnaissance Squadron (WRS) normally flew every other day, along two tracks. One, designated Ptarmigan, involved a 3,500-mile journey, from Eielson Air Force Base at Fairbanks, Alaska, to the North Pole and back. Loon Charlie, the second track, was longer by 100 miles and took the plane and its crew from Eielson to Yokota, where a new crew took over and flew the plane back to Alaska. Together, the tracks flown by the WB-29s put them in position to collect airborne dust traveling eastward from any point in the Soviet Union.96
By September 3 there had been 111 instances in which the radiation count on filter paper carried by a WB-29 had exceeded 50 per minute, a number that resulted in an Atomic Detection System Alert. Each of the first 111 alerts had been explained by natural occurrences—volcanic explosions, earth-quakes, or normal fluctuations in background radioactivity. But Alert No. 112 was the real thing.97
On September 3, a WB-29 piloted by 1st Lt. Robert C. Johnson flew for thirteen and a half hours from Japan to Alaska, at eighteen thousand feet, on the return segment of a Loon Charlie flight that had taken off from Misawa owing to special circumstances. While the flight was uneventful, its aftermath was not. Postflight analysis showed that a filter paper exposed for three hours had a radioactivity measurement of 85 counts per minute. The second filter paper was checked and yielded 153 counts per minute. When word of these developments arrived at AFOAT-1’s well-guarded Data Analysis Center at 1712 G Street, N.W., in Washington, D.C., sometime after dinner on the third, it produced an increase in activity at AFOAT-1 and in the air. Technical director Doyle Northrup and members of his staff were summoned to the center to examine the data. Flights from Alaska to Hawaii and from California to Alaska were scheduled for Sunday and Monday, September 4 and 5, respectively. Subsequently, a special mission covered portions of the Beaufort Sea, to the north and east of Alaska. On Monday evening a report arrived from Japan stating that at ten thousand feet and just to the east of Japan, a filter paper on a WB-29 that had taken off from Guam on a routine weather reconnaissance mission registered over 1,000 counts per minute.98
By the time the aerial monitoring of First Lightning ceased, the Air Weather Service had flown ninety-two special air-sampling flights. In addition, British Royal Air Force planes had also contributed. On September 10, with President Truman’s approval, Britain was informed that a mass of debris-laden air would be passing north of Scotland. A special flight was launched that day from Scotland and journeyed to the Arctic Circle before returning with more debris. Two days later, a routine flight from Gibraltar collected fresh evidence and other special British flights followed. All together, the aerial sampling effort produced over 167 radioactive samples with counts of 1,000 per minute or more.99
Other components of the interim network were checked to see if they yielded any information on what the Soviets had done. The air force’s ground-based filter units produced positive results from Fort Randall in South Dakota, Shemya Island in the Aleutians, and a station in northern Japan. Naval research stations also contributed to the pool of data and debris that analysts would examine. Starting on September 9, gamma ray detectors on a station on Kodiak Island, Alaska, indicated a rise in background radioactivity. The following day air monitors at the NRL in Washington also detected increased radioactivity. Two collections of rainfall from Kodiak, covering the periods September 9–12 and September 13–17, were found to contain large amounts of debris.100
Two elements of the interim network, at first appearance, provided no confirmation that a detonation had occurred. The Army Signal Corps’s network of sensors showed no acoustic waves associated with an explosion, just as the Coast Survey’s seismic network yielded no evidence of seismic waves indicating an atomic blast in the Soviet Union. Such data would have allowed a more precise determination of the location, time, and yield of the Soviet test.101
The initial readings of the filters left much to be done. Beyond verifying that a detonation did occur, there were the questions of when and where, and whether the device was a uranium or a plutonium bomb. The analytical effort spanned the country and the Atlantic, and included some of America’s most renowned scientists.
Beginning on September 6, air force couriers began delivering filters to Tracerlab’s Berkeley laboratory. Lab director Lloyd Zumwalt recalled that “we worked on them through the night.” It was not long before their analyses revealed the presence of fresh fission products on the filters. That the products appeared to have been created simultaneously indicated that they were more likely the result of a bomb than a reactor accident. On September 7, Zumwalt was also able to tell William Urry at the data analysis center in Washington that it was likely a plutonium bomb. By September 10 Tracerlab had concluded that the bomb had been detonated between August 26 and August 29 and that it was a plutonium bomb containing a large amount of uranium, indicating a uranium tamper was employed to help create a chain reaction by reflecting neutrons back into the plutonium.102
The NRL also quickly began to analyze samples produced by the aerial collection effort, and on September 14 its scientists provided an oral briefing to Maj. Gen. Morris Nelson, who had been Hegenberger’s deputy and became his successor at AFOAT-1. The NRL scientists identified the fission products of five elements, but suggested that they should cease work on the air force samples and begin investigating the larger samples that had been produced by the navy’s rainfall collection effort.103
Doyle Northrup also decided to ask scientists at Los Alamos to conduct their own radiochemical analysis of the samples, and on September 10 a filter sample was sent to their radiochemistry group. Weeks before the Los Alamos report arrived in early October, it had become apparent to almost all the experts examining the data that the United States had detected the Soviet Union’s first atomic bomb test, which would be designated both Joe-1 and Vermont.104
There were some high-level doubters who did not believe, or did not want to believe, that America’s atomic monopoly had come to an end. One of the skeptics was secretary of defense Johnson. Another was Truman’s national security adviser Sidney Souers, who hoped there had been a reactor accident. As a result of such doubts, General Nelson asked a panel of scientists, with no air force affiliation, to examine the data. The prestigious group included Vannevar Bush, who had left government service to return to the Carnegie Institution in Washington; former AEC commissioner Robert Bacher; J. Robert Oppenheimer; and Adm. William Parsons, a member of the Military Liaison Committee to the AEC. They were chartered by Gen. Hoyt S. Vandenberg, former intelligence chief and now air force chief of staff, to meet on September 19 to review AFOAT-1’s data and conclusions.105
When the group assembled at 10:00 a.m. on September 20, Bush, who served as chairman, along with Oppenheimer and his colleagues, heard largely oral presentations about the analyses and conclusions of the British, Los Alamos, and NRL scientists. Additional presentations were made by members of the AFOAT-1 staff, and Northrup submitted a three-page memo. The essence of the memo consisted of eleven “facts bearing on the problem” and six conclusions. The facts included the key Tracerlab findings concerning the likely dates that the material was fissioned, the composition of the material, and the presence of uranium, as well as the first results from the Los Alamos and NRL analyses. The memo also reported on the British flights and their results. The main conclusions were those reached earlier in the month: the Soviet Union had detonated a plutonium bomb with a uranium tamper, sometime between August 26 and August 29.106
Estimates of the location of the test site were produced by the six-member Special Projects Section of the U.S. Weather Bureau, one of many small units located in nonsensitive agencies that did very sensitive work during parts of the Cold War. The section was headed by Lester Machta, who held a doctorate in meteorology from MIT. Established in late 1946 or early 1947, it studied the movement of air currents, to assess potential exposure to fallout from U.S. nuclear tests. It included several recruits from the University of Chicago, including Kenneth Nagler and Lester Hubert. Hubert recalls that he was finishing graduate school, where he had studied wind patterns at high altitudes in the Pacific and South Pacific, when he was recruited.107
Based on three possible test dates (August 27–29), the meteorologists produced a series of probability contours, such that for a given date all points within the contour had an equal probability of having been the point of detonation. Their work led to the conclusion, based on AFOAT-1’s estimate that August 27 was the most likely date for the test, that the test site could be found between longitude 35° and 170° east, an enormous expanse of territory that included points west of Moscow and as far east as places in Siberia. The most likely site was somewhere near the northern part of the Caspian Sea.108 That conclusion had two implications: the blast could have occurred almost anywhere in the Soviet Union, but not outside it.
The panelists were convinced by what they heard. The next day they sent a copy of Northrup’s report, along with a cover letter, to Vandenberg. In their letter they told him that it was their unanimous belief that the phenomena detected were “consistent with the view that the origin of the fission products was the explosion of an atomic bomb whose nuclear composition was similar to the Alamogordo bomb,” and echoed Northrup’s memo with regard to the dates and location of the blast.109
Vandenberg passed the letter and attached memo on to Johnson, along with his own memorandum, before the day was out. He told the defense secretary, “I believe an atomic bomb has been detonated over the Asiatic land mass during the period 26 August 1949 to 29 August 1949. . . . Conclusions by our scientists based on physical and radiochemical analyses of collected data have been confirmed by scientists of the AEC, United Kingdom and Office of Naval Research.”110
The following day, Truman, who had received a number of reports on the event over the preceding two weeks, read the Vandenberg memorandum. On September 22 the NRL report was completed and, based on the analysis of collected rainwater, provided further confirmation of the detonation. Then, at eleven o’clock on Friday morning, September 23, after consultations, a review of the evidence with the JCS, receipt of recommendations from Johnson and the AEC, and notification that the United Press would have the story on the street in an hour, Truman told the American public, “We have evidence that within recent weeks an atomic explosion occurred in the U.S.S.R.” He went on to note that such a development had been expected and cited a statement he made in 1945 to that effect. He closed with the observation that “this recent development emphasizes once again . . . the necessity for truly effective enforceable international control of atomic energy.”111
The next day the headlines and substantial portions of the news sections of the New York Times and Washington Post were devoted to the president’s announcement and related stories. “Truman Reveals Red A-Blast” was the Post’s headline. Both papers noted that there was no claim that the Soviet Union had a bomb, although high-level officials warned against assuming that the explosion was the result of a reactor accident. There was also discussion of the various means by which the United States might have detected the blast. The Post noted that some scientists believed the omission of an exact time of the explosion might have been due to its detection by radiological, rather than seismic or sonic, means, although it is unlikely that such information would been revealed even if the United States had it. William L. Laurence, the scientific correspondent for the Times, contributed an article on the Soviet bomb having arrived several years ahead of the schedule predicted by U.S. intelligence and national security officials.112
Identifying the reasons why the Soviet Union shattered the American nuclear monopoly ahead of when the Americans estimated the Soviets “could” have a bomb, much less when it was “most likely” to have one, is not difficult. Some, like Leslie Groves, were privy to the secrets of the Murray Hill Area and Combined Development Trust—projects to locate and purchase as much high-grade uranium ore as possible before the Soviet Union could obtain any—knowledge that had influenced their estimate of when the Soviet Union would break the U.S. nuclear monopoly. They believed that the combination of the trust’s acquisition of the ore and Soviet inability to extract sufficient bomb material from low-quality ore ensured a prolonged U.S. atomic monopoly.
But the analysts at the CIA and the Joint Staff were off in their estimates for other reasons: uncertainty as to when the Soviets began their program, the inability to penetrate the highly secret world of the Soviet bomb program, the lack of complete knowledge about the success of Soviet atomic espionage efforts, and perhaps a failure to appreciate, despite the example of Los Alamos, what a group of highly qualified nuclear physicists could accomplish if given the resources they required. The conditions that the Germans had lacked—scientists who understood how to build a bomb, a country that was not under assault, and the availability of the required resources—were present in the case of the Soviet Union.
The CIA’s failure to provide advance warning of the Soviet test predictably resulted in some tough questioning by some of the legislators who served on the Congressional Joint Committee on Atomic Energy (JCAE). During an executive session on October 17, Hillenkoetter told his audience some of what the JNEIC and CIA had concluded about the Soviet program, including the existence of three water-cooled reactors that used graphite as a moderator. Hillenkoetter could not provide a definite answer as to whether there were other reactors, but he told the congressmen, “We think that that is all they have.” He also estimated that more than 150,000 individuals were involved in the program. Both Hillenkoetter and Dr. Walter F. Colby, the chief of the AEC Intelligence Division, reported that the United States had not picked up any traces of large-scale efforts to separate U-235. Hillenkoetter also acknowledged, in response to a question, that the CIA had not been able to acquire very many, if any, Soviet documents.113
One committee member was particularly concerned with the lack of warning. Senator Eugene Millikin was “very much interested in why we were taken by surprise on the Russian explosion” and observed that “it seems that we muffed it at least a year and maybe longer.” In defense, Hillenkoetter responded, “I don’t think we were taken by surprise,” and then proceeded to explain the reasons for the surprise, including the lack of solid information on when the Soviet program started. Millikin was not satisfied by the admiral’s comments, observing, “We apparently don’t have the remotest idea of what they are doing until after they have done it. . . . I just get no comfort out of anything that the Admiral has said to us. We have not had an organization adequate to know what is going on in the past and he gives me no assurance that we are going to have one in the future.” His judgment was shared by AEC chairman David Lilienthal, who noted at the time, “In my opinion our sources of information about Russian progress are so poor as to be merely arbitrary assumptions.”114
The implications of a Soviet bomb were profound. By mid-1950, the CIA had revised upward its estimate of the Soviet atomic bomb stockpile. It was now projected that the Soviets would possess 10 to 20 bombs by mid-1950, 25 to 45 by mid-1951, 45 to 90 by mid-1952, and 70 to 135 by mid-1953. And U.S. defense spending would have to be adjusted upward as well. Omar Bradley, who was chairman of the JCS at the time, recalled that “the news came as a terrible shock to Louis Johnson. It caught him with his economy ax poised and in mid-air for yet another blow. He swung and continued to swing for some months, but . . . it was clearly a time to build our military forces, not pare them.” Part of that buildup, Lewis Strauss argued, should be a vigorous program to build an H-bomb.115
The lull between Soviet tests would last two years and one day after President Truman’s announcement of Joe-1. Although there may have been a lull in Soviet testing, there was no lull in U.S. attempts to gain further insight into the status of the Soviet atomic energy program. Sometime after the first Soviet test, the CIA contacted a retired mining engineer who had worked in Kyshtym before the 1917 revolution. While there he had overseen many mining operations and had accumulated papers and photos of Kyshtym as well as detailed maps of the entire area. He no longer had the papers in his possession, but was able to tell the agency’s representatives where to find them—in the collection of his papers at Stanford University. The former engineer was also former president Herbert Hoover.116
Additional help in understanding the Soviet program came sometime in 1950 when a colonel in the the Ministry of Internal Affairs (MVD) defected. Icarus, as he was code-named, had worked in the Moscow office of the First Chief Directorate and later at a Soviet-run uranium-mining operation in East Germany. He was able to tell his CIA debriefers the names and addresses of the Soviet Union’s “atomic representatives” in Berlin—information that allowed the agency to begin an extensive investigation of their activities, an investigation that would bear fruit in later years. By mid-1951 the CIA had acquired a sample, manufactured in East Germany, of material used in U-235 production.117
The agency was also able to report that a fifth large Hanford-type plutonium production reactor might be under construction and that between 340,000 and 480,000 persons were working full-time on the Soviet atomic bomb effort. There was considerable uncertainty, however, in a number of areas, according to the JCAE staff. While the CIA “appears to have established the location of many Soviet project sites with some certainty (largely through the aid of refugees from Russia) . . . relatively little is known about the kind of plants actually established at these sites.” In addition, estimates of the number of graphite and heavy-water reactors and the size of U-235 plants “are based in large measure (the Committee staff understands) upon the amount of raw materials assumed to be on hand.” While the CIA’s information on raw materials in Eastern Europe and European Russia was quite good, “there is no proof that the Soviets have not discovered rich uranium sources in Siberia.”118
The two technical components of the detection system that had moved beyond the formative stage remained the key elements of the monitoring effort in the early 1950s. The Army Signal Corps continued operating the acoustic stations and providing reports to AFOAT-1. By May 1951 the United States was sampling the air masses moving out of the USSR and over the Middle East. Flights were conducted once every seventy-two hours over a limited flight path from Dhahran, Saudi Arabia, to Lahore, Pakistan—a frequency that was not sufficient to intercept all the clouds moving out of the area. The lack of backup ground filter units in the Near East made the deficiency more serious. At the time, Britain was in the process of equipping with filters the Royal Air Force Transport Command aircraft that flew daily round-trips between London and Singapore, with stops in Libya, Iraq, Pakistan, and India.119
A SECOND ELEMENT of aerial atomic intelligence operations was even more sensitive than test detection. Its genesis can be found in Luis Alvarez’s idea to monitor Germany for signs of xenon-133, to determine if a plutonium production reactor was in operation. That gas was not the only noble gas emitted as a by-product of plutonium production. Krypton-85 was another. It also does not occur naturally in the atmosphere and is only found there if some nation put it there. If the United States could determine the amount of krypton-85 emitted from Soviet reactors, it would be possible to estimate the amount of plutonium produced, since the number of grams of plutonium produced is directly proportional to the number of grams of krypton-85 produced by the fission of U-235 in a reactor. In the process of dissolving uranium to recover plutonium, krypton-85 gas is released into the atmosphere along with the dissolving gases in an amount proportional to the number of grams of plutonium recovered.120 An estimate of the amount of plutonium produced could help determine the number of plutonium bombs that might be carried on Soviet bombers.
In June 1950, the Ad Hoc Committee on Atomic Energy, reporting to the Intelligence Advisory Committee (which consisted of the chiefs of America’s major intelligence organizations), recommended maintenance and active support for such an effort. Since U.S. spyplanes could not overfly Soviet reactors to obtain direct readouts of the level of krypton-85, the effort required a more complex approach. It required that U.S. and British analysts, based on the results of aerial sampling, determine the worldwide level of krypton-85, which had stood at zero in 1944, and subtract from it the contribution due to non-Soviet reactors. What was left was the Soviet contribution. By late March 1951, scientists determined that it would be possible to calculate the post-1945 releases of krypton-85 from the Hanford facility as well as from the reactor at Chalk River, Canada. If, as expected, the British began plutonium production later in the year, it would be necessary to add that amount to the U.S. and Canadian totals. In addition, AFOAT-1 and the AEC had worked out a method of measuring the worldwide level of krypton-85, and it was expected that before the end of the year it would possible to estimate that level to within 5 percent of the true value. On July 1, the Research and Development Board’s committee on atomic energy estimated that by mid-1952 it would be possible to produce a quantitative assessment of Soviet krypton-85 production “with a precision equal to ten percent of U.S. generation.”121
BY 1951, there had also been some progress in expanding the network of ground stations used to gather atomic intelligence. In July 1950, the first ground filter units, designed to trap radioactive debris, were produced and installed at McClellan Air Force Base in California, at Eielson in Alaska, and on Guam. Beginning in 1950, the Special Weather Unit, under the control of the air force, began operations at Puerto Montt in Chile, and was probably involved in similar operations. Near the end of 1950, or early the next year, the first seismic station dedicated specifically to the Atomic Energy Detection System, as the AFOAT-1 monitoring network was called, was installed near College, Alaska. In April 1951, Team 301, which operated both seismic and acoustic equipment, began operating in Ankara, Turkey.122
That was only the beginning of several attempts, some immediately successful, to establish such facilities on allied territory. In September 1951, Frederik Møller, the director of the Norwegian Defense Research Establishment (NDRE), received a request from Colonel McDuffy of the U.S. Air Force, requesting permission for an American team to search Norway for suitable sites for seismic and acoustic detection stations. The stations would be operated for two years by an American staff and then turned over to Norway. In Washington that month, the Danish ambassador was told during a meeting at the State Department that the United States was interested in installing a ground filter unit at Thule, Greenland.123
MEANWHILE, AS THE U.S. and allied intelligence services tried to uncover their secrets, Soviet bomb designers worked to improve the plutonium bomb design that their spies had stolen from the United States—something they believed, even before the August 1949 test, could be done. Sometime in 1949, Yakov Zeldovich, at the time head of the theoretical department at Arzamas-16, and three of his colleagues—E. I. Zababakhin, Lev Altshuler, and K. K. Krupnikov—drafted a proposal for a bomb that would halve the weight of the plutonium bomb while doubling its yield. V. M. Nekrutkin suggested a different means of producing implosion, which made it possible to significantly reduce the bomb’s diameter.124
The result of their work, RDS-2, exploded at 9:19 on the morning of September 24, 1951, at the Semipalatinsk test site, with a yield of just over 38 kilotons. Joe-2 was followed by Joe-3 less than a month later. On October 18, RDS-3, dropped from a Tu-4 Bull bomber rather than placed on a tower, detonated with a yield of 42 kilotons. The successful tests resulted in Kurchatov and Khariton each being named a Hero of Socialist Labor for the second time.125
The data collected on the September 24 blast by U.S. detection systems was reviewed by a panel reporting to the Defense Department’s Research and Development Board. The panel, which included Oppenheimer and Bacher as its members, concluded that “there was a fission explosion on 24 September 1951 . . . in the vicinity of Lake Balkhash.” The conclusions as to the time and place of the detonation were based on its detection by the experimental acoustic network, which had exhibited improved performance since 1949. While the time was correct, the center of Lake Balkhash is about 350 miles from Semipalatinsk—but still far closer to the actual test site than “somewhere near the Caspian Sea” as estimated in 1949.126
The panel also reported on the preliminary analysis, which indicated that “an implosion weapon using plutonium was fired.” Further, the scientists concluded that at the time of their review there were no indications of U-235 having been employed and the results were “inconsistent with the presence of any large amounts of this material.”127
The October test would be followed by another lull, one that would last for almost two years. But while there was no testing activity, the Soviet program continued to develop during that time, just as it did during the period between the first and second tests. In 1949 the gaseous diffusion plant at Sverdlovsk-44 had been unable to produce uranium enriched to more than 75 percent, requiring the electromagnetic separation facilities at Sverdlovsk-45 to be employed to raise the enrichment level to 90 percent. In 1950 the technical difficulties at Sverdlovsk-44 were overcome and the plant was able to produce tens of kilograms of uranium each year, enriched to the 90 percent level. In July 1950 the second of the Chelyabinsk-40 production reactors became operational, an event that would be repeated by four additional reactors by the end of 1952. To further augment the plutonium production capabilities of Sverdlovsk-44 and Chelyabinsk-40, yet another facility was established in 1950. This one, Krasnoyarsk-26, was located on the Yenisei River, about thirty-one miles to the northeast of Krasnoyarsk.128
In December 1951 the Soviet Union moved toward mass production of atomic bombs when the Avangard Electromechanical Plant (Plant 551), established in 1949 to produce twenty RDS-1–type bombs a year, and located near Arzamas-16, produced its first bomb. The year 1951 also witnessed the completion of the second gaseous diffusion plant at Sverdlovsk-44.129
THE SOVIET TESTS of 1951 would be followed by another hiatus, which also lasted about two years before being shattered by a dramatic Soviet advance. During that interval the United States experienced both success and setbacks in building its network to monitor future tests.
In January 1952 Norway’s Møller replied to McDuffy and informed him that due to political considerations, his country’s minister of defense demanded that the stations be partly staffed by Norwegians. The original plans then underwent substantial revision, with five stations becoming two “micro-meteorological research stations,” and received the defense minister’s approval. However, for reasons that are not clear, the plan would lay dormant for several years.130
The request to the Danish ambassador proved more successful. In October 1952, Team 220 was established at Thule Air Base. A few months earlier, in May, a mobile seismic station, Project Rockpile, was set up in Korea. A number of seismic-monitoring devices were also located in Iran. The operation, known as B/65, involved at its peak three officers and thirteen enlisted personnel above and beyond those assigned to the air attaché’s office, which was employed as a cover by the AFOAT-1 personnel.131
However, by the end of 1952 the shah’s continuation of power in Iran seemed problematic. The air force’s Directorate of Intelligence expressed concern to the air attaché in Iran about the security of the AFOAT-1 operation. As a result the seismic and acoustic instruments covertly located at four sites on a hunting preserve were removed. However, to avoid the “impression of lack of confidence in the shah,” the instruments were replaced by dummy boxes and the removal was made to appear as a routine overhaul.132
Despite such setbacks, the detection organization commanded at the end of 1952 by Brig. Gen. Donald Keirn, a former liaison officer for the Manhattan Engineer District, had grown to eight hundred employees. It also utilized the services of hundreds of other personnel and dozens of additional agencies both in the air force and outside of it.133
Late 1952 also saw an organizational change that would prove important to the atomic intelligence effort. On October 24, 1952, in a top-secret, eight-page memorandum on communications intelligence activities, President Truman abolished the ineffective Armed Forces Security Agency (AFSA) and transferred its personnel to the National Security Agency (NSA), created earlier that day by a draft of National Security Council Intelligence Directive No. 9 (which would be formally issued in December).134 Whereas AFSA was unable to exercise significant supervision over the military COMINT agencies, NSA, as befitted its name, would serve as a national manager—and atomic intelligence was one of the most national of intelligence requirements.
FOR MUCH of his time at Los Alamos and after, while others were consumed with developing an atomic bomb and then improving it, Edward Teller focused on the possibility of an even more destructive weapon—a hydrogen bomb or “Super.” The explosive force of such a bomb would come, not from fission, but fusion. Two isotopes of hydrogen, deuterium (extracted from water) and tritium, would be fused to form a nucleus of helium and a neutron. The energy released in the process would be far greater than that released from fission, with bomb yields in the megatons rather than kilotons. On January 31, 1950, President Truman publicly authorized the development of such a bomb, and in March issued a secret directive that labeled the project “a matter of the highest urgency” and authorized the production of up to ten H-bombs a year.135
Between his initial proposal and Truman’s authorization of the project, Teller had produced a number of alternative designs for the bomb. Ultimately, he would have to share credit with mathematician Stanislaw Ulam. A 1951 suggestion by Ulam, and its modification by Teller, resulted in the concept of radiation compression—using the radiation (X-rays) rather than the shock wave from an atomic bomb to compress the thermonuclear fuel. Compression would make the fuel burn faster, ensuring that heat production out-stripped heat loss in the fuel. Their design also involved separating the fission bomb (the primary) from the thermonuclear fuel (the secondary) and using the bomb casing to channel the radiation produced by detonating the primary toward the thermonuclear fuel of the secondary.136
On November 1, 1952, Mike, as the test of the device produced according to the Teller-Ulam theory was designated, resulted in the incineration of the Pacific island of Elugelab, substituting a crater about two hundred feet deep and a mile and a half wide. The yield of the explosion was more than 10 megatons, exceeding expectations by 50 percent—an “outstanding success,” as Lewis Strauss would write several months afterward. For the test, the deuterium was maintained in a liquid state by a massive refrigeration system, which turned the device into a 50-ton, two-story “bomb”—not something one could load onto a bomber.137
Just as Edward Teller began thinking about a hydrogen bomb before design work for the first atomic bomb had been completed, Soviet physicists considered the possibility of employing fission as the first step in producing a fusion reaction. The first was Yakov Frenkel, who headed the theoretical department at Ioffe’s institute. He raised the issue of a fusion bomb in a September 1945 memo to Kurchatov, who was already aware of the possibility because of his access to the intelligence on the American efforts provided by the NKVD and GRU. That month Soviet intelligence obtained reports on aspects of the “classical Super” that Teller had proposed. Another intelligence report from 1945 provided information on means of boosting the yield of a fission bomb through the fuel used in a hydrogen bomb.138
Kurchatov instructed Khariton to investigate, in collaboration with Zeldovich and two other physicists. On December 17, Zeldovich read their report, Utilization of the Nuclear Energy of the Light Elements, to the Technical Council of the Special Committee. Khariton and his colleagues recommended setting off a nuclear explosion in a deuterium cylinder through “nonequilibrium combustion.”139
In the succeeding years, while Kurchatov and Khariton continued working on the primary task of developing an atomic bomb—first by copying the U.S. design and then developing their own—Soviet physicists at home and intelligence officers abroad continued their investigations concerning fusion. In London, on September 28, 1947, Soviet intelligence officer Aleksandr S. Feklisov met with spy Klaus Fuchs and posed ten questions, the first of which concerned the Super. Fuchs told Feklisov of the studies being conducted by Teller and Enrico Fermi. A little over a month later, in early November, Zeldovich reported to the First Chief Directorate the latest research results of the group that he headed (which had been established in June 1946). Their report mirrored American thinking of the time, in that it envisioned the shock wave from a fission bomb igniting the thermonuclear fuel.140
The program escalated in 1948, with Zeldovich being placed in charge of operations at KB-11 in February, Fuchs delivering materials containing new theoretical information on the Super in March, and the Council of Ministers approving a resolution in June that ordered the Sarov design bureau to investigate, both theoretically and experimentally, all possible advanced atomic and hydrogen bombs. The resolution also mandated a role for the Physics Institute of the Academy of Sciences of the USSR. The hydrogen project was given the code name RDS-6. Another resolution directed that a special theoretical unit be established at the physics institute under fifty-three-year-old Igor Tamm, who had organized the institute’s theoretical department in 1934—and would share the 1958 Nobel Prize with two other Soviet physicists for his work on the “Cerenkov effect.”141
Among those working in Tamm’s group was Andrei Sakharov, who at age twenty-seven was Tamm’s junior by well over two decades and had joined the Academy of Sciences physics institute in 1945, three years after graduating from Moscow State University. In September and October 1948 Sakharov came up with an idea, analogous to the “Alarm Clock” concept conceived by Edward Teller—a bomb consisting of layers of fusion material (lithium-6 deuteride) placed into concentric shells of an enlarged implosion device—apparently without any access to intelligence about Teller’s notion. The Sloika, translated as “Layer Cake,” also would rely on alternate layers of deuterium and U-238. In January, Sakharov issued his report on the new concept, which drew strong support from Khariton. Sakharov then found himself being ordered by Beria to attend an almost weeklong series of conferences held in Sarov in early June to review the status of the atomic and hydrogen bomb projects. It was Sakharov’s first visit to the secret city, where he would spend eighteen years of his life. The key result of the conference was a scientific research plan that called for work on both Sakharov’s Layer Cake design and on the Truba (Tube)—the name for the Soviet version of the classical Super. Sakharov himself would devote himself solely to finding ways to transform his idea into reality.142
His idea took another step toward being transformed into an actual weapon the following February, when the Special Committee passed a resolution, “On Measures to Develop the RDS-6.” The First Chief Directorate, Laboratory 2, and the design bureau at Sarov were instructed to organize further theoretical, experimental, and design work to construct both the Layer Cake (RDS-6s) and the Tube (RDS-6t). Khariton was appointed as director of operations for their construction, and Tamm and Zeldovich were named his deputies. The RDS-6s was to have a yield of 1 megaton and weigh up to 5 tons.143
A variety of measures were investigated to produce the thermonuclear fuel needed for the bomb. The fuel was not deuterium and the expensive, hard-to-produce tritium that had originally been thought necessary. In November 1948 Vitali Ginzburg, a member of Tamm’s group, suggested that lithium deuteride, a compound of lithium-6 and deuterium, was a preferred alternative. Not only would lithium deuteride, a chalklike solid, be easier to handle than tritium and deuterium, but lithium-6 would produce the required tritium during the explosion when it was bombarded by neutrons. At Ioffe’s institute in Leningrad, Boris Konstantinov developed an effective and cheap method of obtaining lithium-6, but one that required a new plant. A member of Lev Artsimovich’s group at Laboratory 2 eventually developed a method for separating lithium isotopes and produced enough lithium-6 to fuel the Layer Cake device. The process for producing the required deuterium was developed at the Institute of Physical Problems in Moscow, which had been established in 1934 as consolation prize for Peter Kapitza when he was forbidden to return to the English laboratory where he had spent the previous thirteen years.144
On June 15, 1953, Tamm, Sakharov, and Zeldovich signed the final report on the development of RDS-6s, which estimated that the device would explode with a force of between 200,000 and 400,000 tons of TNT. This time the Soviet scientists did not have to fear Stalin’s reaction if the test did not live up to expectations, since the Soviet dictator had died two months earlier. And by the end of the month they no longer had to worry about Beria, who was arrested on June 26 by Stalin’s successors and charged with assorted offenses, including being a “bourgeois renegade” and “agent of international imperialism.” His arrest was followed first by his replacement by Viacheslav Malyshev, deputy chairman of the Council of Ministers, and then by his execution. The First Chief Directorate became the Ministry of Medium Machine Building.145
Even if Stalin and Beria had been around, they would not have been able to complain about the results of the first test of Sakharov’s bomb. When it was tested at Semipalatinsk on August 12, 1953, it produced an explosion measured at 400 kilotons, at the very top of the estimated range. Sakharov recalled that he had taken a sleeping pill the night before and turned in early. He rose, along with the others who were there to witness the test, when alarm bells at the hotel went off at four in the morning. Two and a half hours later he reached his station, about twenty miles from his bomb, where he was to watch the test with other young scientists from Sarov.146
In his memoirs Sakharov recalled the moment of detonation and the aftermath:
We saw a flash, and then a swiftly expanding white ball lit up the whole horizon. . . . I could see a stupendous cloud trailing steamers of purple dust. The cloud turned gray, quickly separated from the ground and swirled upward, shimmering with gleams of orange. The customary mushroom cloud gradually formed, but the stem connecting it to the ground was much thicker than those shown in the photographs of fission explosions. More and more dust was sucked up at the base of the stem, spreading out swiftly. The shock wave blasted my ears and struck a sharp blow to my entire body; then there was a prolonged, ominous rumble that slowly died away after thirty seconds or so. Within minutes, the cloud, which now filled half the sky, turned a sinister blue-black color.147
THE LAYER CAKE was certainly different from the standard fission bomb, American or Russian. Whether it was truly a thermonuclear bomb was another question. At the time it was the position of the Joint Atomic Energy Intelligence Committee (JAEIC), as the JNEIC had been rechristened in late November 1949, that “a field test of a device involving a thermonuclear reaction is within Soviet capability at any time.” But that judgment was not based on hard evidence. In March 1952 air force secretary Thomas Finletter had characterized U.S. intelligence on the subject as “meager.” At the beginning of 1953 the JAEIC and CIA issued an estimate which stated that “there is no evidence of thermonuclear development activities at the present time.” Among the factors considered were the individuals involved in the Soviet bomb program. The only concrete warning came courtesy of Soviet premier Georgi Malenkov, during an August 8 speech to the Supreme Soviet, when he claimed that the United States no longer “had a monopoly” on the hydrogen bomb.148
Then, on August 12 the United States detected seismic signals and subsequently collected airborne, and possibly rainfall, debris that indicated a possible Soviet test. When AEC chairman Lewis Strauss returned to Washington on August 19, after a trip to New York, and conferred with other members of the commission, acting director of central intelligence Gen. Charles Cabell, and acting secretary of state Walter Bedell Smith, he discovered that two possibilities needed to be eliminated before the United States could be sure that the Soviets had tested an atomic or thermonuclear weapon: that the signals were not the result of a concurrent earthquake in the Greek islands and that the debris did not originate with a previous U.S. test. Strauss was assured by AFOAT-1 representatives that they would have definitive information that afternoon.149
At six o’clock that evening Strauss received a call from Cabell, who told him that a report on the scientific findings would be ready at about 8:30 that night and that he would bring it to his office. The meeting that began at 8:30 included Strauss, several other commissioners, Cabell and three other members of the CIA, State Department representative Gordon Arneson, and AFOAT-1 technical director Northrup. Northrup told them that while his organization’s conclusions were incomplete, there was no doubt that a fission and thermonuclear reaction had taken place within Soviet territory. At 10:30 Strauss received a call from a member of the AEC staff who informed him that Moscow radio had announced that the Soviet Union had tested an H-bomb in the last several days.150
The following day, Strauss told the world, “The Soviet Union conducted an atomic test on the morning of August 12. Certain information came into our hands that night. Subsequent information on the subject indicates that this test involved both fission and thermonuclear reactions.”151
A panel of scientists whose charter was to review information from Soviet atomic and nuclear weapons tests took another look at the data. The Foreign Weapons Evaluation Panel was better known as the Bethe Panel, taking its name from chairman Hans Bethe, who had left Los Alamos to return to teaching and research at Cornell, his first position in the United States after arriving from Germany in 1935. While no longer a government employee, he still played a major role in advising the national security bureaucracy on weapons and intelligence issues, and was instrumental in developing techniques to distinguish between a fission explosion and a thermonuclear blast. The panel also included Enrico Fermi, Richard Garwin, who for over forty years would play a key role as an outside adviser to U.S. intelligence organizations on technical issues, and Lothar W. Nordheim.152
Bethe and his colleagues examined the seismic and acoustic data that had been obtained as well as the data that had been produced by subjecting the debris to mass spectrographic and radiochemical analyses. Seismic data was considered the best means of estimating yield. Even so, analysis of that data indicated a yield of between 500 kilotons and 2 megatons, with the most likely value being 700 kilotons. Acoustic data indicated a somewhat lower yield.153
The first of the general conclusions about “Joe-4,” and undoubtedly the key conclusion, based on analysis of the debris, was that “there must have been a substantial thermonuclear reaction.” But the presence of a substantial thermonuclear reaction did not make the device a true thermonuclear bomb, in the view of Bethe and others. The JCS Joint Intelligence Committee concluded in October that the test represented the Soviet counterpart to Teller’s Alarm Clock bomb rather a true hydrogen bomb. In his report Bethe noted that its conclusions were “subject to considerable doubt” and that “it is a bold undertaking . . . to determine both the composition and the geometry of a bomb which you have never seen,” while also writing that “certain conclusions are much more firm than others.” One of the conclusions he considered firm concerned the proper classification of RDS-6s. Almost thirty years later, he would write that “this was not a true H-bomb . . . it was not the real thing.” Richard Garwin agrees, noting that the test was “the first large scale burning of thermonuclear material, [but] not radiation implosion by any means.”154
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* Seismic techniques involved detecting the waves that would pass through the earth’s surface in the event of nuclear detonation. Such techniques were already in use for detecting earthquakes. Sonic techniques detected the sound waves created in the atmosphere from a detonation.