tldr: satellites are retired by using up their fuel reserves in order to get them to burn out in atmosphere or "park" in a higher orbit. Some satellites have timers built in in case their receivers fail and do this automatically.
Essentially, when something goes wrong satellites stay in stable orbits as space junk, their batteries decay and become conductive so the sun starts powering directly when conditions are met, at this point we can catch telemetry from these space-age relics. Beyond cool.
Wow, after listening to these I have a lot more respect for the cheesy "beeps and boops" sound effects used in so many 1960s and 1970s movies to connote satellite stuff. Turns out they really did sound like that!
tldr: satellites are retired by using up their fuel reserves in order to get them to burn out in atmosphere or "park" in a higher orbit. Some satellites have timers built in in case their receivers fail and do this automatically.
Essentially, when something goes wrong satellites stay in stable orbits as space junk, their batteries decay and become conductive so the sun starts powering directly when conditions are met, at this point we can catch telemetry from these space-age relics. Beyond cool.