Plasma Armor is a powerful energy field which projects from ships serving the NSEA. The armor is specifically designed to protect any vessel that it's generating from, however after sustained hits over time, the energy that makes up the armor's durability will begin to dwindle until there is nothing left to protect the ship.
Galaxy Quest (1999)Edit
After retaking the Protector II from Sarris' men, Alexander Dane engaged the ship's plasma armor before flying into the Tothian Minefield. Once using the ship's metal to drag the mines, the Protector flew straight at Sarris' ship, accelerating at mach 4 and evading the opposing vessel before they crashed. By that time, the armor was almost completely gone, however they didn't need to re-engage as the mines destroyed the enemy vessel.