* Had a completely unarmed ship and told it to attack a Pirate Base (which I had made mad). Command completes immediately. No attack.
* Gave turret a command and told the ship to attack again. Same result.
* Loaded missiles into the ship. Same result.
* Loaded one gun to turret, turret command 'None', no missiles. Ship proceeds to attack. One installed gun only. No command to use it. Next time I look, the 3 GJ shield of Base is gone and hull has scratches. Single gun. Weak gun. Disabled gun. And the ship still hits really hard.

* Uninstalled the gun. Ship continued its attack. Okay, the 'Attack ..' checks on start if the ship has a gun, but not again. No more damage to Base.
* Transferred Firestorms to the ship. One launches immediately and almost wipes out the Base. Couple seconds later second missile vanishes from the hold, and so does the Pirate Base.
Conclusions:
* Turret commands are not required for ship to use installed weapons OOS.
* Attack power of the ship is a complete mystery.
* 'Attack ..' requires installed gun.
* Missiles are consumed OOS.
* Missiles do damage OOS.
Other observations:
* Only small fraction of Xenon ships has Missile firing probability other than 0%.
* Strong patrol ships are known to die, but not often.
* Xenon Patrols and Pirates can carry Hammerheads.
* Xenon Patrols and Pirates can quickly destroy even 5--7 GJ of shields.
All that seems suddenly very logical. Missiles.