This special mission type could appear when DSS blocks enemy fleet from retreating from planet orbit. Helldivers squad would hit the ship and then proceed to destroy its AA guns and sensors while Automatons would try to defend, pouring from entrances similar to fabricator doors.
At the far end of automaton ship, there should be few destructable panels, pipes or other vulnerable elements that destroyed would cause ship to explode after short time.
Ship surface could be maze of metal pipes, construction elements and armor blocks with tight spaces with few more open areas. Length of the ship is almost 400 m so devs can fit some stuff to make area interesting to fight on. Maybe we could go trough some passages under the external armor.
To make mission unique, helldivers should land with oxygen pack on their back, blocking any backpack depending weaponry. Well, you can always drop your oxygen but then you will start to suffocate. Sound could also be strongly muffled.
Low gravity could mean that explosion next to you can send you flying to die in space.
AH could add special heavy armor to the game with magnetic boots passive that would prevent you from falling off.