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?

They go to whatever planet the Warlord commits to. However, if you DON'T commit your Warlord to the first planet, then like any other Army unit, they DON'T return to HQ again at the end of the round. They remain at the planet and then refresh during the HQ phase (assuming they're still alive at the HQ phase).

Short answer: don't always pick first planet when you commit

Also, don't forget that you still get the card/resource bonus from them when you win a command struggle at the planet, even if they are exhausted. So if they are headed to a planet from the HQ with your warlord, that is probably a good thing.

oh...ok...I thought that their abilities were not usable if they were exhausted after arriving at a planet with the warboss ( like any other non-warboss army unit ) in much the same way that they cannot be used for their command icons when they're exhausted. Is there somewhere in the rules which states that a cards abilities can be used even when exhausted? If I've overlooked that I'd like to be able to know where it is so that i can display this to other players.

I actually forgot that too ktom (not played in a good while though).

oh...ok...I thought that their abilities were not usable if they were exhausted after arriving at a planet with the warboss ( like any other non-warboss army unit ) in much the same way that they cannot be used for their command icons when they're exhausted. Is there somewhere in the rules which states that a cards abilities can be used even when exhausted?

It's more the other way around - that there is nothing in the rules that says a card's effect can't be used when the card is exhausted (the way that the rules say a unit's command icons do not count toward a command struggle while it is exhausted).

However, the clarification that card abilities are active even when the card is exhausted (unless something specifically says otherwise) is on page 4 of the FAQ .