Discoverer 11 was a USAF photographic surveillance satellite designed to assess how rapidly the Soviet Union was producing long-range bombers and ballistic missiles, and where they were being deployed. It was part of the Corona program which was also used to produce maps and charts for the Department of Defense and other US government mapping programs.
The satellite used a film canister that was returned to earth in a capsule (a.k.a. bucket) for evaulation. These capsules were designed to be recovered by a specially equipped aircraft during parachute descent, but were also designed to float to permit recovery from the ocean. All film were black and white. Discoverer 11's film capsule recovery failed.
The Discoverer program was managed by the Advanced Research Projects Agency
of the Department of Defense and the U.S. Air Force. The primary goal of
the program was to develop a film-return photographic surveillance satellite
to assess how rapidly the Soviet Union was producing long-range bombers and ballistic missiles and where they were being deployed, and to take photos over the Sino-Soviet bloc to replace the the U2 spyplanes. It was part of the secret Corona program which was also used to produce maps and charts for the Department of Defense and other US government mapping programs. The goal of the program was not revealed to the public at the time, it was presented as a program to orbit large satellites to test satellite subsystems and investigate the communication and environmental aspects of placing humans in space, including carrying biological packages for return to Earth from orbit. In all, 38 Discoverer satellites were launched by February 1962, although the satellite reconnaissance program continued until 1972 as the Corona project. The program documents were declassified in 1995.