Question about EMP shields


So I understand that it doesn’t make the ship immune to EMP weapons, but only gives it a chance to resist EMP hits. My question is if having multiple modules of EMP shields carries any benefit? Would multiple modules further reduce the chance? Can enough modules make the ship immune or only approach immunity, that is to ask, is the hit chance reduction additive or multiplicative?

The reason I’m asking is I’m considering options for dealing with the Orion Ambush survival mission when after surviving the plasma cruisers, my cruisers get swarmed by emp missle firgates and seem to get permanently EMP stunned. I did try fitting my cruisers each with an emp shield, but the benefit is marginal when they are getting hit by so many emp missles in succession. Sure, some are resisted, but enough arent that they are still practically stun-locked. I’m still in awe of CopperD’s high scores, so I’d like to figure out a strategy that can both deal with the plasma cruisers and the emp frigate swarm.


The hit chance reduction is additive, but the modules do not stack in a linear way, but with a 30% reduction for each additional module. You can see the effectiveness of a module by hovering your mouse over it on the design screen.
Maybe a better tactic is to shoot down the EMP missiles with point defence weapons.