Pretty much explained in the title, but the tooltip doesn't clarify if Rapid Decay is shield penetrating. I assume it is since the damage is physical. I observed these numbers on a battleship in an old Federation Patrol mission as proof of the missing shield pen:
[2:19] [Combat (Self)] Your Rapid Decay I gives 567 (3628) to Talon Battleship's Shields.
[2:19] [Combat (Self)] Your Rapid Decay I deals 403 (2801) Physical Damage to Talon Battleship.
the damage is consistent on all ticks (567 (3628) to shields and 403 (2801) to hull)
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