The early spy satellite cameras were cutting edge for the era, in both their makeup and the resolution of the pictures they took. Going back to those spy satellites in the CORONA program, each camera system aboard was between five feet and nine feet in length with a resolution of roughly 40 feet from an orbit of 100 miles up. The resolution of their images would improve over time as would their coverage of the Earth. By the end of the program on May 31, 1972, the CORONA program had photographed 750 million square miles of the Earth’s surface!
Satellite cameras that could provide panoramic pictures and make it easier to spot Soviet missile silos, made their way to space in the early 1970s. The HEXAGON KH-9, satellites for instance utilized optical bar cameras to do just that while taking pictures of objects two feet across or smaller. Its tour of duty would end in 1986 having taken 877 million square miles of pictures.
