Nuclear espionage
George Koval – The American born son of a family that was from Belarus. He moved to the Soviet Union where he joined the Red Army and the GRU intelligence service.  He found his way into the US Army, and became a radiation health officer. He got information about the Urchin detonator used on the plutonium bomb that was dropped on Nagasaki, Japan.  His work was not known to the United States until 2007, when he was recognized after his death as a hero of the Russian Federation by Vladimir Putin.