Babd Catha Forerunner vessel

"Commander, you're wondering what your Spartans died for? They died for this."

- Doctor Catherine Halsey

This enormous ship of Forerunner design was embedded within the Babd Catha Ice Shelf on Reach at some point before 2552. Positioned at a tilted angle, the ship was appeared to be roughly disk-shaped; as most of it was buried by a glacier, its true size is unknown. Parts of the ship were visible in an ice cavern underneath SWORD Base, as well as a nearby mountain range. The interior of the complex houses a holographic Forerunner data terminal of some kind.

History
The complex was home to one of Dr. Catherine Halsey's labs and had evidently been under excavation by the Office of Naval Intelligence for some time. By summer 2552, ONI had marked a number of artifact sites that seemed to form a trail leading from CASTLE Base, the site of the Menachite Forerunner complex, to the immediate region of SWORD Base, suggesting that the ship was outbound along this trajectory when it crashed.

According to Dr. Halsey, the complex held secrets that could turn the tide of the Human-Covenant War — a "latchkey" discovery that Halsey compared to the invention of the conical bullet and the Shaw-Fujikawa Translight Engine. However, when the Covenant began attacking the facility on August 29, 2552, the decryption was only partially complete. Using Wolf Spider turrets, SPARTAN-III NOBLE Team was able to hold off the Covenant for long enough until Halsey could finish the decryption. The complex, along with SWORD Base, was completely destroyed by an explosive charge.

Exactly what data Halsey discovered within the complex was never revealed, but the data apparently contributed to the discovery of Halo Installation 04.

Trivia

 * The ship was designed by Bungie environment artist Paul Russel.
 * In a commentary video for the multiplayer map Breakpoint, one of the map's designers presented the idea that the reason for the structure's tilted angle and unusual placement was a result of an accident with teleportation. However, he was quick to denounce the canonicity of the idea.

List of appearances

 * Halo: Reach