Mostly, but we have no idea (confirmed) what the Air Force's space plane does. We know it exists, we can track it while in orbit, but what it does do while there is not public. Also, the software and other capabilities of a lot of satellites are inferred but not 100% known.
So these birds are privately doing things in a public, ahem, space.
It's nothing new. There were numerous classifieds Shuttle missions 30+ years ago that are still classified. People have more or less figured out what these missions were, but they're still classified and and a lot of the details still aren't known.
Interesting anecdote from one of them (STS-27):
> The day after Atlantis landed, the 1988 Armenian earthquake killed tens of thousands in the Soviet Union. At an astronaut meeting Gibson said, "I know many of you may have been very curious about our classified payload. While I can't go into its design features, I can say Armenia was its first target!" As military astronauts laughed and civilians cringed, Gibson continued, "And we only had the weapon set on stun!"
(Turns out it was actually a synthetic aperture radar recon satellite, not an earthquake machine.)
So these birds are privately doing things in a public, ahem, space.