[tullianus]

Often you can figure out what spacecraft/rocket a piece of debris came from with a good catalogue of orbits and some math - these are labeled "Debris." Often you just can't - these are labeled "Unknown."

The US Space Force does a lot of the object cataloging, and they occasionally will pretend one of their classified satellites doesn't exist, but there's only a handful of these.

[3pt14159]

> but there's only a handful of these.

Huge if true.

[tullianus]

Oh, there are plenty of US satellites with classified payloads/missions; I just mean that most classified US satellites DO have orbital elements listed in the Space Force catalog.

[aerostable_slug]

I'd add that it would be pointless to try to hide a fair number of them, given that they approach the size of school buses (no joke — the now-retired KH-9 was nicknamed "Big Bird" for good reason) and can be imaged on relatively consumer-ready optics. Some Russians made a nice stink a few years ago by using (IIRC) laser illumination to make some relatively high-res shots of American recce sats.

The interesting aspects of them have to do with how far off-axis they can function. This was the major consequence of loss of the Morison leak of the KH-11 shots of a Soviet carrier to Jane's Defense Weekly — the image revealed how far off-axis it could image and some clues to how it processed imagery.

[bagels]

Often not in the public catalog though.