High Quality Content by WIKIPEDIA articles! Adolf Georgievich Tolkachev Адольф Георгиевич Толкачёв (1927, Aktyubinsk, Kazakhstan – 1986) was a Soviet Union electronics engineer who provided key documents to the U.S. Central Intelligence Agency (CIA) over the years between 1979 and 1985. Working at the Soviet radar design house Phazotron as one of the chief designers, Tolkachev gave the CIA complete information about such projects as the R-23, R-24, R-33, R-27, and R-60, S-300; fighter-interceptor aircraft radars used on the MiG-29, MiG-31, and Su-27; and other avionics. The United States considered the most advanced airborne radar among the systems Tolkachev compromised was the passive phased array radar used by the MiG-31 Foxhound fighter. He was executed as a spy in 1986.