Orbital Defense Grid

The Orbital Defense Grid is the main defense for the planet Earth. Established by the United Nations World Defense, the grid is a web of interconnected satelltes that have sensor beams that fire from one satellite to the other. The grid has Defense Satellites and mines scattered around, most unpredictably. If a Chimera ship passes through a sensor, it is attacked by satellites and homing mines aswell as the planet's defense fleet. The Orbital Defense Grid is what has kept major invasions from Earth since the 1980s.