Declass 3 (2013) = USGS Subset of Hexagon Missions - KH-9: 1971 - 1984
'Keyhole (KH) satellite systems- KH-9 acquired photographs of the Earth\'s surface with a telescopic camera system and transported the exposed film through the use of recovery capsules.  The capsules or buckets were de-orbited and retrieved by aircraft while the capsules parachuted to earth.  The exposed film was …