ship-guardian Causes the ships listed in this sexpression to not be killable by weapons. Use with caution!!!! Takes 1 or more arguments... 1+: Name of ships to make unkillable.
Allows ships to take damage but not be destroyed; their hull becomes invincible once it reaches 1%, although all other subsystems can still be damaged. This is useful for situations where the realistic effect of a ship being damaged is required, but the ship must also survive. Simply making a ship invulnerable once it goes below a certain hull strength is not as reliable, as the ship may be destroyed anyway if it takes too much damage too fast just as the invincibility is coming into effect. If you want to keep a ship's hull above a certain percent, use ship-guardian-threshold.
Note that if you use this as a tactic to keep plot-critical wingmen alive you will end up with a battlefield strewn with disabled fighters. If you dislike this, there are many ways to solve the problem in SCP (but you don't have many options in Retail). For example, you can use ship-subsys-guardian-threshold on the engines. If you want to limit a ship's combat capability once it is damaged (so that the player doesn't become too dependent on invulnerable wingmen), disable the ship's weapons when its hull is badly damaged using turret-lock, lock-primary-weapon or lock-secondary-weapon, or, for fighters, simply destroy the weapons subsystem.