From Halopedia, the Halo wiki
The Tiara was a space station in equatorial geosynchronous orbit over Utgard, on the human colony Harvest. It supported the seven space elevators servicing the colony's capital city of Utgard, and functioned as an orbital port for passenger and cargo transport, as well as the storage area for the data centers of the AI Sif, who was in charge of Harvest's shipping operations and maintaining the Tiara's position.
The Tiara was not present in 2502, but was fully functional by 2524. During the First Battle of Harvest, a large engagement occurred inside the Tiara. The Covenant forces that arrived at the planet, from the cruiser Rapid Conversion, took control of the station and created outposts for its soldiers. The Jiralhanae left the Unggoy, from the cruiser, to guard all of the outposts, with Deacon Dadab in charge. Later in the battle, Harvest's human colonial militia attempted to retake the station. Harvest's civilians were being loaded up from the planet's space elevators into freighters attached to the station to escape Harvest. The militia engaged the Covenant soldiers with the Jiralhanae and Yanme'e actively looking for the humans, while the Unggoy attempted to hold their posts.
It, along with Sif, was destroyed in 2525 when Loki fired Harvest's mass driver from the surface of the planet, just before Harvest fell to the Covenant. The strands wrapped around Harvest, as per its rotation and the remnants of the Tiara fell into Harvest's atmosphere. In a state of grief, Mack, Harvest's agricultural AI, used the numerous JOTUNs under his control to bury the elevator strands of the Tiara, protecting them from plasma fire as Harvest was glassed by the Covenant.
The Tiara is described as two arcs separated by the carbon nanofiber strands that made up the space elevators of Harvest. The beam work connecting the elevator strands to the arcs resembled delicate filigree. Six beveled titanium spars ran the length of the facility. Avery Johnson estimated the station was about 4 kilometers long and its interior around 300 meters in diameter (13,200 and 990 feet, respectively). It possessed some form of artificial gravity as well. The station was protected from minor hull breaches by a layer of sealant foam between its double hulls.
List of appearances