FERRET

Clandestine flights conducted during the Cold War to test Soviet and other hostile countries’ radar response to incursions of their airspace. The objective was to penetrate the hostile territory, monitor the local air defenses, and identify the location of radar stations, surface-to-air missile sites, and airfields operating interceptor aircraft. Ferret flights into Soviet airspace resulted in the loss of 12 aircraft and 69 aircrew between 1945 and 2000. A further 81 Americans died in incidents involving North Korean and Chinese air defenses over the same period, and in 1992 the  National Security Agency confirmed that 64  cryptographers had died on air reconnaissance missions during the Cold War.