>Look as recently as the Manhattan Project' It didn't stay too secret, Soviet atomic spies penetrated the program. Emil Julius Klaus Fuchs for example was con

>Look as recently as the Manhattan Project' It didn't stay too secret, Soviet atomic spies penetrated the program. Emil Julius Klaus Fuchs for example was convicted of supplying information from the American, British, and Canadian Manhattan Project to the Soviet Union during and shortly after the Second World War https://www.wikiwand.com/en/Klaus_Fuchs https://www.wikiwand.com/en/Klaus_Fuchs https://www.wikiwand.com/en/Atomic_spies https://www.wikiwand.com/en/Atomic_spies has other info about the spying attempts during the time.