My dad was involved on our end of spying on the Soviets with our satellites. They were usually placed in polar orbits so they would pass over the entire globe eventually as the earth rotated below them. In the 60s digital imaging was not developed enough to get high resolution so they used conventional film cameras shooting different film, sensitive to different wave lengths. The IR film could pick up all kinds of heat patterns from objects that were no longer there. Once the film was exposed it was moved to a capsule, ejected to de-orbit and recovered on reentry. Radio frequency data was also recorded by other satellites and "downloaded" to tracking stations to be recorded and later analyzed. Commands to control the satellites were "uploaded" to the birds as they called them. That was the first time I had ever heard the use of those two terms, (upload/download) that now are part of everyday Internet jargon.
