The identity of the spy of the Soviet Union, who managed to infiltrate the US nuclear bomb program in the 1940s and is perhaps the man who gave the most and most important information to Moscow about the atomic bomb, they reveal declassified US documents.
Oskar Szeborer, child of Polish immigrants, of Jewish descent, born in New York in 1921, studied electrical engineering at Ohio State University, was drafted in 1942 and ended up working on the Manhattan Project, the top-secret US program to create the first atomic bomb while he was also present at the first nuclear explosion test, named Trinity.
At the same time, however, Seborer was also a spy for the Soviet Union, with the code name "Godsend", i.e. the "Theostaltos", since for the Soviet nuclear program and because of the information he delivered it was literally that.
Historians Harvey Clare and John Earl Haynes, in a new paper, reveal the extent of Szeborer's espionage activity, with the information drawn from declassified CIA documents, which contain untold details about Szeborer, who defected to the USSR in 1951. . "It is exciting. We had no idea he was so important," Clare told the New York Times.
During his involvement in the Manhattan Program, Seborer helped build some of the most important components of the first nuclear bombs, such as the firing circuits, and was instrumental in helping the nuclear warhead shrink in size and be able to carried in a rocket.
In particular, Seborer designed an "incredibly complex" fusion detonator, which ensured a symmetrical spherical compression in the nuclear warhead, necessary to set off the chain reaction that gives the nuclear bomb its terrifying power.
Alex Wellerstein, a nuclear historian at the Stevens Institute of Technology in Hoboken, New Jersey, told the Times that the Soviets "spent a lot of time researching the firing circuit," noting that Seborer's contribution "must have been unique" among other spies who had infiltrated the Manhattan Project.
"I don't know if any of the other spies had access" to Seborer's secrets, he told the Times, noting that Seborer and his colleagues "may have filled in some gaps" by helping Soviet scientists.
For example, a June 1946 Soviet design for a nuclear bomb cited by Wellerstein, dated four months after Seborer left the Manhattan Project, shows that the firing circuit is clearly inspired by American design.
The CIA documents are dated 1956, four years after Seborer fled to the Soviet Union. Clare told the newspaper that the FBI found evidence of possible spying by Seborer in 1955, but although other Soviet spies such as Klaus Fuchs were arrested and their discovery made public, the 1956 presidential election coupled with yet another spying scandal , would embarrass the US.
However, the evidence against Seborer was also very sketchy. The documents do not detail his espionage work, only noting what he might have intercepted and handed over to the Soviets, based on the material he had access to. Additionally, he was already in the USSR, so even a criminal prosecution against him was unlikely.
"It's entirely possible - let sleeping dogs sleep," Clare said, adding "but you can't prove it." The paper by Clare and Haynes notes that an FBI informant in Moscow had reported that Seborer had stated that if he or his brother Stewart returned to the US, they would be sent to the firing squad "for what they had done".
In 1953, the US had executed two people suspected of espionage, Julius and Ethel Rosenberg, on charges of supplying the Soviets with plans for the Manhattan Project. The USSR detonated its first atomic bomb just four years after the American Trinity test in August 1949.