From The Vault
Alien Turrets (simply called Turret ingame) are the alien equivalent of Automated Turrets, encountered on board Mothership Zeta.
In contrast to Automated Turrets, only ceiling-mounted versions of this turret exist. While they cannot be shut down or frenzied via a terminal, it is possible to remotely detonate them using nearby switches aboard the Mothership. They explode in a blast of green plasma, similar to a Plasma Grenade, when detonated via switch and can be frenzied if their targeting chip is shot at. They are unable to shoot directly below them.
[edit] Appearances
Alien Turrets appear in the Mothership Zeta Fallout 3 add-on.