The platforms feature an array of medium and long range missiles as well as an extremely powerful particle beam weapon. On its own, a single Aegis has enough firepower to wipe out the entire eastern seaboard of North America. Collectively, the planetary defense grid has the potential to level up to 40% of the Earth's populated surface using its particle beam weaponry.
Morgan Clark had programmed these platforms to fire upon Earth after his death, in keeping with his Scorched Earth policy. Senator Crosby and her people were unable to override the system to keep the platforms from carrying out Clark's last vindictive act. The entire network was destroyed by John Sheridan's fleet before they could fire on Earth.
By 2266 a replacement network had been seeded in Earth orbit, and were used to try to prevent the Drakh plague ships from reaching Earth. While they were able to shoot down some of the Drakh ships, they were unsuccessful in keeping the Drakh from seeding Earth with their plague. 
|Earthforce Ship Classes|
|Olympus-class corvette · Hyperion-class heavy cruiser · Nova-class dreadnought · Omega-class destroyer · Advanced Omega-class destroyer · Warlock-class destroyer|
|SA-23E Starfury · SA-32A Thunderbolt · Stealth Starfury · Heavy Starfury · Badger-class Starfury|
|Earthforce One · Magnum heavy lifter · Breaching pod · Troop Transport · Kestrel Class Atmospheric Shuttle · Crew Shuttle|
|Aegis orbital defense platform · Life pod · Work pod · Gunship · Explorer class ship · Cotten class Deep Penetration Tender · Shadow Hybrid · Shadow hybrid fighter|