The Manhattan Project espionage refers to a series of Soviet intelligence operations, beginning in 1942 and continuing through 1949, that gathered technical information about the American-led effort to build the atomic bomb. The most important single source was the German-born British physicist Klaus Fuchs, who provided Moscow with the design of the implosion bomb; the most politically explosive was the Rosenberg network in New York, which provided material of less technical importance. The Soviet program was substantial enough that the first Soviet atomic device, RDS-1, detonated on August 29, 1949, was closely modeled on the American Nagasaki design. For more on the famous-spies article; the Rosenberg case that the espionage produced is detailed separately.
Soviet intelligence work on the bomb began in late 1941, after the British MAUD Committee’s report reached the United States. The NKVD’s rezidentura in New York, under Anatoly Yatskov, was instructed in 1942 to identify and cultivate American scientists with access to atomic research. The first breakthrough was the recruitment of Klaus Fuchs in 1941, by an NKVD officer working in the United Kingdom. Fuchs, who was a member of the British Communist Party, was already an agent of the German Communist Party’s intelligence apparatus; he had been turned, in 1937, while a student in Bristol. After his transfer to the British atomic-bomb project, he was handled by the NKVD’s London station and, later, by the New York station.
The Fuchs case
Fuchs was the most important of the wartime atomic spies. He was a theoretical physicist of considerable ability; he was a member of the British team at Los Alamos from August 1944 to June 1946; he was a senior member of the theoretical-division group working on the implosion design; and he was privy to the most sensitive discussions of the design and the progress of the project. Between 1944 and 1946 he passed to his Soviet handler — a courier he knew only as “Raymond” — a series of technical memoranda on the implosion design, the plutonium production process — the predicted yield of the Nagasaki bomb. The information he provided was the basis for the first Soviet implosion design.
Fuchs was uncovered in late 1949. The British Security Service (MI5), informed by the Venona decrypts, had been working on the Soviet network since 1948. The identification of Fuchs was made by the FBI’s analysis of Venona, working in parallel with GCHQ’s analysis. On January 27, 1950, Fuchs was interviewed by MI5; he confessed. He was tried in a British court in March 1950, convicted under the Official Secrets Act, and sentenced to fourteen years’ imprisonment, the maximum at the time. He was released in 1959, after serving nine years, and emigrated to East Germany, where he became a deputy director of the Central Institute for Nuclear Research at Rossendorf, near Dresden. He died in 1988.
The case had a direct consequence. Fuchs’s confession identified Harry Gold, an American courier, as his Soviet handler in the United States. Gold identified David Greenglass, the Los Alamos machinist, as a second source. Greenglass identified his brother-in-law Julius Rosenberg as the leader of the New York network. The chain of identifications led to the arrests, in 1950, of Greenglass, Julius and Ethel Rosenberg, and Morton Sobell.
The Rosenberg network
The Rosenberg network included Julius Rosenberg, his wife Ethel, his brother-in-law David Greenglass, and several others. The most discussed, in the scholarship, is Julius’s own role. The Venona decrypts identify him as a member of a Soviet network — “Liberal” and “Antenna” — that was in contact with the New York rezidentura and that handled a variety of technical material. The most serious material the network provided was, in the assessment of most historians, more limited than the prosecution’s case claimed. Greenglass’s account, in which he claimed to have provided detailed sketches of the implosion lens, has been substantially undermined by the technical evidence: the implosion lens was a complex optical system that a machinist would not have been able to sketch accurately, Soviet implosion design was, in fact, based more directly on the Fuchs material than on the Greenglass material.
The most authoritative single work on the Rosenberg network is John Earl Haynes and Harvey Klehr’s Spies: The Rise and Fall of the KGB in America (2009), which uses the Venona decrypts, the post-1991 releases of Russian archival material, and the U.S. government’s own files. Haynes and Klehr conclude that Julius was a Soviet agent who did pass information about the atomic project, that the information was less significant than the prosecution claimed, and that the death sentence for both Rosenbergs was a miscarriage of justice. The case is, in their treatment, a clear case of a real spy case that was prosecuted in a politically overheated atmosphere, with an excessive sentence and an unfair trial on a key point (Ethel’s role).
Other cases
The Manhattan Project espionage also involved:
- Theodore Hall, a young American physicist at Los Alamos who was, on the evidence of the Venona decrypts, a Soviet source from 1944 to 1945. Hall was never prosecuted; he was identified by the FBI but was, on the evidence, never investigated with the same vigor as the Rosenbergs.
- Oscar Seborer, a British physicist at Los Alamos who has been identified in the Venona decrypts as a Soviet source. Seborer was also never prosecuted.
- David Greenglass, the machinist, whose case is detailed above.
- Morris Cohen and Lona Cohen, an American couple who were also involved in the New York network and who fled to the Soviet Union in 1951. They later lived in the United Kingdom as Soviet illegals until their deportation to the USSR in 1969.
The cumulative effect of the Manhattan Project espionage was real but more limited than Cold War mythology suggested. The Soviet program benefited substantially from the Fuchs material, but the program was also home-grown, staffed by a substantial body of Soviet physicists, and capable of independent work. The Soviet bomb was a Soviet achievement. The espionage accelerated it by perhaps two years — the figure most often cited, including in the work of the Soviet physicist and dissident Andrei Sakharov — but it did not produce the bomb.