Corona declassification (1995)
The US government declassified roughly 860,000 images from the Corona spy-satellite program (1959-1972), making the first high-resolution overhead imagery of Earth public. The release also confirmed a reconnaissance program Washington had long denied.
Researchers gained decades of historical landscapes, and the public saw what spy satellites had captured at the height of the Cold War.
Declassification helped normalize civilian access to satellite imagery and opened the field for commercial operators.
Every widening of public satellite data—Corona's release, free Landsat, Planet's open TLE feed—has expanded civilian access to what was once military-only.
