If I have a void pirate or rogue trader card at the first planet and they go to the HQ how does it work as far as ever being able to be used for their bonuses in the proceeding command struggles? They go back to any other planet with the warlord exhausted, and thus would not be usable in the command struggle in the turn they arrived in ( or any other one thereafter as far as I can see? ).
Do they just get discarded once the planet they're on is scored or otherwise disappears?