Babylon 5 Starship Defensive Systems

While a wise Earth man once said ‘the best defense is a good offense’ there are some shipbuilders and purchasers in the galaxy who disagree – they would rather have better defenses hands down. Races like the Abbai, Brakiri, Humanity and the Pak’ma’ra have all but mastered the use of defensive fire, chaff rounds, flak cannons and the like in order to soften incoming attacks or stop them altogether.

Armor protects a ship from taking too much damage once it has already been hit, whereas defensive measures hopefully keep the ship from being hit at all. The idea being that if no weapons can get through the defenses, it will rarely need to worry about amour stopping damage at all.

Any ship can add defensive measures just as they would any other type of weapon or ship feature retrofit. Once in place the defensive component will act like a separate weapon system that can be fired as an ‘Interceptor’ or as an offensive tool. They are not designed to cause massive amounts of damage, so they are rarely useful against anything except fighter craft if used offensively.

Active defenses are commonly interceptor turrets or shield generators and require crew attention to work properly, but are generally effective against most types of weapons.

Defense Grids
Advanced Defense Systems
Shield Generators

Source
Babylon 5: Ship Builder's Manual (pages 66-69)
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