The Planetary Defense System is a weapon featured in Jak 3. It is found in the center of the catacombs. The Precursors designed the weapon to strike down any Dark Maker ships that approach Earth, it is powered by the eco power sphere, which combines the power of both light eco and dark eco by combining the power of four of each color's eco crystal and amplifying the power. It is stationed around the Precursor core, and when first revealed, contains a large oracle statue, a platform, and the larger barrels themselves.
The Planetary Defense System is first mentioned by Veger some time after Jak returned to Haven City. He mentioned that the Precursor Monks gave him the knowledge to activate the system, though he noted that he would only activate it if he were begged to do so. When Jak looked through the astro-viewer the first time, the Precursors told him that the system was the only hope for defeating the threat of the Dark Makers.
Near the end of the game, the weapon finally charges up and destroys the Dark Maker ship, eliminating the bulk of the threat except for a Dark Maker terraformer that Cyber Errol crash landed into the Wasteland before the ship was destroyed. Jak later destroys the terraformer and Cyber Errol.