You may build and store up to 60 fighters in a starbase and you may put fighters on board any starship equipped with fighter bays. The fighters onboard a starbase will be used to defend the base and planet against attacks from enemy starships.
If a planet comes under attack the fighters on a starbase and the fighters on the planet's surface are launched against the attacking ship. Defense posts on the planet's surface and the defense weapons on the starbase will be fired against the attacking ship. The higher the defense strength of both the planet and the starbase, the greater number and power of the planetary beam weapons.
The defense_factor = 100 + starbase_defense + planet_defense
You can compare this defense factor with starship defense factors, which are equal to the empty hall mass of the ship.
Defense factor is the resistance to enemy fire, in both shield strength and damage resistance after the shields are down.
The number of beam weapons that a planet/starbase has equals the square root of one third the defense factor.
number_of_beams = SQR( defense_factor / 3 )
The tech level of the beam weapons is the square root of one half the defense factor or the beam tech level of the starbase, which ever is higher.
tech_of_beams = SQR( defense_factor / 2 )