Like nearby Aventen, Caelax was named for an ancient philosopher and author. But where Aventen wrote for the military leaders of tomorrow, Caelax focused on those who feed, clothe, heal and arm the soldier. Her enormous tome, "Service" features a lengthy chapter on laws that formed the basis for the turian concept of citizenship tiers. Caelax is lower in temperature than Aventen, and its minerals were thus exploited first.
The turian defenses on Caelax are not completely destroyed, which is unusual. It may be that remnants of the scattered turian fleet regrouped using the planet for cover, and eliminated the satellite-hunting Reaper destroyers before their mission was complete. More likely, the destroyers found a way to compromise the defenses through wireless hacking, and the unmanned drones present now obey them.