Fighting
You can use your base defenses to fire at any enemy fleet within the system the base is in.
You can fire thru your fleets, and if your fleet is orbiting your base you can add battery fire to any attack by it attack any of your batteries. If your fleet is on orbit over one of your allies bases, you can also use his base's unshielded batteries.
Deflection Shields extend its shields to all ground batteries
Planetary Shields extend its shields to all owner in orbit fleets
[unfinished]
