Perimeter defense

"Having now established a secure perimeter, we have made ourselves relatively safe from enemy incursions. But against the seemingly random attacks by Planet's native life only our array of warning sensors can help us, for the Mind Worms infiltrate through every crevice and chew through anything softer than plasmasteel."

- Lady Deirdre Skye, "The Early Years"

Perimeter Defense is a base facility in Alpha Centauri.

Effect
Increases defense multiplier of base by oneThis effectively doubles defense strength (or triples it when combined with a Tachyon Field)