[manquer]

That makes sense,

I guess you can look at the orbit parameters ? I am assuming if the satellites are not yet on station they won't share the exact same plane as those that are in station. They are elevated over few months as they are spread to the right position I believe

[gpm]

Yes... or maybe better would be to monitor whether or not the orbital parameters for any particular object are changing over time. If they're still using the ion thruster they're not on station...

It would take a fair bit of work on making the heuristic robust, so I don't plan to do it. If you're interested in doing so feel free to download the source (just scrape it from the website) and go at it.