The CIA’s Corona satellite program deployed a series reconnaissance satellites to spy on the Soviet Union and China between 1959 and 1972. The spy satellites would take pictures on films made by Kodak, since digital cameras were not invented until 1988. These films were sent back to earth in canisters as large as garbage cans. The canisters had parachutes that would deploy upon entry into the atmosphere. Special air-force units were set up to intercept these chutes mid-air. In case a pilot was unable to snag a canister, it would fall into the Pacific. It would then be retrieved by rescue swimmers. (Source)