When they return to their homebase, the Duke Military Zeus and escorts destroy them. They respawn, and the cycle repeats.
Moreover, these boarding ships carry pods but no marines! How am I supposed to get the
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"You have been duked" achievement? Tried mission-generated Carracks instead and managed one of them to collect boarding pods I've dropped, but they just don't launch marines. Can Duke's M7Ms pick up astronauts?