The structure referred to as Sentinel Base was situated on a moon located within a far-flung system found in the Arkanis sector of the Outer Rim's territories. Like the other Sentinel bases, it existed to safeguard the construction efforts related to the Death Star battle station.
The design of Sentinel Base was that of a pre-made station, intended for deployment to its designated location on the Sentinel moon through the use of a starship. What began as a confined garrison base eventually expanded into a sizable complex featuring interconnected domes and hangars, with additional modules that were either pre-built or assembled on-site, along with an adjacent landing field and a deflector shield generator. Given its strategic significance, it typically benefited from the protection of a fleet composed of several capital ships and smaller vessels, including the frigate known as the Salliche, the tug named Fremond, and the Imperial-class Star Destroyer called Core Envoy.
The original modules for Sentinel Base, a pre-fabricated garrison base, were transported by a Victory-class Star Destroyer in 21 BBY, during the period of galactic conflict known as the Clone Wars. Its purpose was to oversee the delivery of supplies and otherwise protect the highly classified Galactic Republic project that was under construction in the neighboring Geonosian space.
Following the transition to the Galactic Empire, the Imperial Military assumed control of the base, continuing its function of supporting the construction of the battle station, which had by then evolved into the Death Star, throughout the Empire's reign. Initially, it was under the command of Vice Admiral Dodd Rancit, but by 17 BBY, he was replaced by Moff Wilhuff Tarkin by direct order of Emperor Sheev Palpatine himself.
In 14 BBY, a group of rebels attacked the base utilizing outdated Separatist technology, including a cobbled-together warship. Tarkin and his forces were victorious, although the capital ship managed to escape before it could be rendered inoperable.