If I'm running the numbers right, then using the Hubble's maximum theoretic angular resolution of 2.8e-7 rad[1], something 400km up would still not resolve features smaller than 11.2cm. That's the absolute best, diffraction-limited case. Don't know how close we are to that on real-world optics.
There's probably a way to circumvent these limit by using multiple satellites working together[1], combining images to form a synthetic aperture[2], using an aperture mask[3], or a combination of any or all of those. Actually I'd be surprised if state-sponsored spy agencies were not already using this.
I forgot about synthetic apertures! IIRC the Event Horizon Telescope result had to include the model of what the black hole probably looked like to refine the image, it would be fascinating to see what could be done by a constellation of telescopes in LEO. Though the [3] link says that aperture masking only gets you to the diffraction-limited regime.
[1] https://opentextbc.ca/universityphysicsv3openstax/chapter/ci...