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Discoverer 21



Discoverer 21 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.

Like Discoverer 19, it carried no film capsule. Its purpose was to test whether the rocket engine could be restarted in space.

Alternate Names

  • 00084
  • 1961 Zeta 1
  • Discoverer21

Facts in Brief

Launch Date: 1961-02-18
Launch Vehicle: Thor
Launch Site: Vandenberg AFB, United States
Mass: 1110 kg

Funding Agency

  • Department of Defense-Department of the Navy (United States)


  • Surveillance and Other Military

Additional Information

Questions and comments about this spacecraft can be directed to: Coordinated Request and User Support Office

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