Why load a warhead less powerful than the Mark IX?
Short answerSome missions require destroying a base or other target without destroying the planet, so the maximum yield is often the wrong effect.
NotesA viewer asks why the ship should carry anything less destructive than a Mark IX warhead. Maximum yield is not automatically useful when the actual objective is a base or another limited target. A planet-crushing weapon can make the desired political or military outcome impossible even when it destroys the aim point. A mixed magazine gives commanders proportional options instead of forcing every strike into the setting's highest level of destruction.