Can special traits, such as Countermeasures, Point defence, Fire Control be purchsed more than once per ship?
And if so, do they both work in a cumulative way, or would the additional systems in effect just be a backup if you were using the rule that allows specials to be destroyed?

For example, if a ship has 2 x countermeasures, is the a 2 modifier to hit it instead of one?
If a ship had double fire control, could it negate both long range and countermeasures at the same time?

Thanks,

Andy