Declassification
The Corona program was officially classified top secret until 1992. Then, on February 22, 1995, the photos taken by the Corona satellites, and also by two contemporary programs (Argon and KH-6 Lanyard) were declassified under an Executive Order signed by President Bill Clinton. The further review by photo experts of the "obsolete broad-area film-return systems other than Corona" mandated by President Clinton's order led to the declassification in 2002 of the photos from the KH-7 and the KH-9 low-resolution cameras.
The declassified imagery has since been used by a team of scientists from the Australian National University to locate and explore ancient habitation sites, pottery factories, megalithic tombs, and Palaeolithic archaeological remains in northern Syria.
The "CORONA Digital Atlas of the Middle East Project" hosts a large number of KH-4B imagery where users can view and download spatially corrected images.
Read more about this topic: Corona (satellite)