The activities around the then-classified Corona spy satellite program were disguised as a scientific program, and the satellites were called "Discoverer" in media releases. Each satellite carried a re-entry vehicle which contained the exposed film taken by the satellite's camera. The film buckets were ejected from the satellite over Alaska, and re-entered along a North-South ground track, ending near Hawaii. The USAF used modified C-119 and C-130 aircraft to catch the film buckets as they descended under their parachutes.
After the Corona program was declassified in 1995, the US National Reconnaissance Office released an oral history of the program, as told by the flight crews who retrieved the satellite payloads. It is now available as a free PDF download.