| Defense Perimeter | |
|---|---|
 Building in Beyond Earth | |
| Cost | 150 
|
| Maintenance | 1  Energy
|
| Requires | Defense Grid |
| Specialist slots | None |
| Effect | +40 City Hitpoints +10 City Defense |
| Notes | None |
History[]
In the late stages of Old Earth’s “Cold War,” various nations developed so-called “semi-automated ground environments” (SAGE) composed of networked computers and defense systems to serve as a unified defensive grid. The outer perimeter of colonial SAGE sites was composed of sensors, “soft” fortifications, magazines and autonomous weapons systems, all utilizing natural terrain barriers and all linked by computerized communications systems to a central command center. The second layer of the defensive perimeter was composed of fixed particle and beam weapons (later directed by orbital platforms) and telerobotic (later autonomously robotic) AFVs. The distance from the settlement of the defensive perimeter varied; some were but a few kilometers out, others many. The initial intent was to protect the settlements from the indigenous lifeforms, especially the speedy raptors and large Siege Worms. Although the soldiers were capable of tackling these beasts, the defensive perimeter could evaluate the threat and react to contain it until their arrival. As time passed and research on this planet progressed, and as the threat from the alien animals decreased but that from competing colonies increased, the defensive perimeters became more sophisticated and lethal. Long-range sensors and various radars, lidars and sodars were added, as well as uplinks to orbital surveillance satellites communicating directly with the now-autonomous computer networks overseeing the perimeters, although this raised security concerns among some colonists.