I love all the ranting about the Chinese Spy Balloon, when we know that both the U.S. and China have fleets of spy satellites that can probably provide a close-up of an ant's face on the ground from anywhere over the other's country. Talk about political theater. Jeez.
@lauren Close-up of ant's face requires, charitably, 100 μm resolution. Can't orbit below about 200 km; 300-800 km is much more common. 100 μm at 200 km is 0.5 nanoradians. To get an Airy spot diameter 1.22 λ/d of 0.5 nanoradians with blue light of λ = 450 nm, you need d = 1.22 · 450 nm / 0.5 nanoradians = 1100 meters. Is not plausible that either US or China has a spy satellite currently in orbit with an 1100-meter-diameter mirror, much less a fleet of them.
Additionally to neither country having the requisite rockets to launch a satellite the size of a small town yet, would be 19 arc minutes in diameter when it passed overhead, two thirds of the visual diameter of the sun or moon. Wouldn't help moving it to a higher orbit because the mirror would have to be proportionally bigger.
Photos you see of cities on Google Maps "satellite view" are mostly aerial photos, not satellite photos, for this reason.
@radehi Yeah, I know how this stuff works. I was making a point about all the balloon hyperbole, not presenting a scholarly discussion of U.S. surveillance capabilities. But hell, if you want to play that game, check out the ants from the movie "Them!" (1954).
