Today (11-12-22) residents near Cape Canaveral heard a distinctive double sonic boom that's usually indicative of a returning spacecraft. The Shuttle is retired and SpaceX had nothing on the menu. It turned out to be the Space Force's highly classified and totally mysterious X-37 returning after spending 908 days in space! That's approaching three years! (It still has "USAF" written on it.)
The military isn't talking about what these uncrewed mini-space-shuttles are doing up there for such long periods of time. So all we have is speculation. That ranges from spy cameras in the payload bay, to long-endurance battery and propellant management tests.
The military isn't talking about what these uncrewed mini-space-shuttles are doing up there for such long periods of time. So all we have is speculation. That ranges from spy cameras in the payload bay, to long-endurance battery and propellant management tests.