Three formerly classified U.S. reconnaissance satellites are going on public display at the National Museum of the U.S. Air Force, the Dayton, Ohio-based museum announced Jan.24.

The three Keyhole-class satellites — Gambit 1 KH-7, Gambit 3 KH-8 and Hexagon KH-9 — used specially designed film and cameras to take photos from orbit from the 1960s to the 1980s. The National Reconnaissance Office (NRO), whose very existence was once a secret, led development of the satellites.

The satellites will be displayed as part of the Air Force museum’s Cold War Gallery and will eventually be placed in the museum’s planned fourth building, which will house the Space Gallery, among other exhibits.

The three satellites made their public debut last September at the Smithsonian National Air and Space Museum’s Udvar-Hazy Center outside Washington during a short public exhibition coinciding with the NRO’s 50th anniversary gala.