Defense Outposts

Defense posts protect the planet from attacking starships. Cost of building a defense post is 10 megacredits and one supply unit. The maximum number of defense posts you can build on a planet is limited by the size of your colonist population.

Defense posts will screen the planet's industrial activity from long range sensor sweeps by enemy ships. The odds of detection are (100 - NUMBER OF DEFENSE POSTS * 6.66 )%.
The number of fighters that a planet can launch to defend the planet from enemy ship attacks equals SQR (NUMBER OF DEFENSE POSTS). Fighters from a planet are regenerated after each attack.
When there is not enough manpower on the planet to maintain structures on the planets surface the structures will decay at a rate set by host. The rate is the number of undermanned structures that can be lost in a single turn. If it is set to 3 than up to 3 of each type of structure can be lost in a single turn on a planet that does not have enough colonists to support. This applies to mines, factories and defense outposts.