The space shuttle was funded and designed to meet Department of Defense specifications. Its cargo bay designed to ferry satellites up and to potentially return them back to earth.

https://www.space.com/34522-secret-shuttle-missions.html

https://launiusr.wordpress.com/2012/11/12/nasas-space-shuttl...

https://en.wikipedia.org/wiki/Category:Department_of_Defense...

The Hubble design was remarkably close to Keyhole:

https://space.stackexchange.com/questions/3448/was-hubble-re...

Keyhole satellites were seriously cool. Photos were taken on film, and the film reels were jettisoned over the ocean. C-130 transports would capture the payloads as they parachuted back to earth:

https://www.cnn.com/2016/09/01/us/declassified-spy-satellite...