> IMHO, space is big + satellites are hard to track, if they're highly-maneuverable or designed to be stealthy = possibility of launching untracked microsatellites that couple with space assets and wait for activation
From what I've read, I understand it to be more of the opposite: there's nothing to hide behind in space, and NORAD and NASA track nearly every piece of debris in orbit, not to mention satellites. So it would be hard for an adversary to do anything like that sneakily, even if there might not be any countermeasures (unclassified ones, anyway). I'm no expert, of course.
From what I've read, I understand it to be more of the opposite: there's nothing to hide behind in space, and NORAD and NASA track nearly every piece of debris in orbit, not to mention satellites. So it would be hard for an adversary to do anything like that sneakily, even if there might not be any countermeasures (unclassified ones, anyway). I'm no expert, of course.