During Stalin 's purges , Berg was imprisoned for three years , but was freed and rehabilitated in 1940 , when Stalin became interested in developing radar . Berg was immediately appointed as minister of electronic technology of the USSR . He developed the Redut-K air-warning radar which was placed aboard the light cruiser '' Molotov '' in April 1941 . '' Molotov '' ´s device enabled her to play a key role in the air defense of Sevastopol in the first stages of Operation Barbarossa
Stalin 's purges
Great Purge
Aksel Berg