Sivvi, also known as the Thule Moon, was an asteroid that was captured by the gravity of Thule, becoming the planet's moon.
Upon becoming trapped in the planet's gravity, Sivvi was often referred to simply as the Thule Moon. Approximately 4,000 years before the Battle of Yavin, the Sith established a military training facility on the moon, using Sivvi's natural caves and tunnels to practice zero-gravity maneuvers.
During the Clone Wars, Sivvi housed a planetary shield generator to protect a base established by the Confederacy of Independent Systems on Thule. This generator was destroyed by Anakin Skywalker, piloting an All Terrain Experimental Transport, during the final stages of the Dark Reaper crisis, leading to a Republic assault on Thule itself.
- Star Wars: The Clone Wars: Prima's Official Strategy Guide
- Geonosis and the Outer Rim Worlds
- The Complete Star Wars Encyclopedia, Vol. III