Save the Turrets is a challenge in the Eridium Blight worth 10 Badass Ranks, taking place at the beginning of The Talon of God story mission. It is unique among area-specific challenges in that it may only be attempted or accomplished once per playthrough.
While Claptrap opens the security door to Hero's Pass, two Auto Cannons (or turrets) materialize, initially hostile. Claptrap hacks them to become allies, and protecting them from destruction completes the challenge.
The Vault Hunter can damage and destroy the turrets while they are hostile, preventing challenge completion. Exiting the game to redo the mission is also possible if at any point a turret goes down.
An alternate method is to simply hang back near the New-U Station by Claptrap's waiting point. Some boxes provide cover, and while Surveyors may still fly close by, the waves of Loaders may be killed at long range. At this distance the turrets do not appear, and so the mission skips their conversion into allies. The challenge is completed once the area is clear; although the Vault Hunter should proceed with caution as the turrets do appear and fire when approaching the open door to Hero's Pass.