Holotank

Holotank displaying Cortana.

The holotank, also referred to as a holo-projector, is a device used to project a hologram. A variety of different sizes and shapes of holotank exist, and the term is used to refer to both UNSC^[1] and Covenant^[2] devices. Small holotanks commonly used by AIs are often referred to as holo-pedestals.

UNSC

Holotanks are used to project a hologram of information and are sometimes reserved for AIs, though other information can be displayed, such as mission recordings and holo-vids. UNSC holotanks vary greatly in size and shape, ranging from small cylindrical pedestals reserved for AI avatars to large tables used to display tactical information.

Covenant

The Covenant commonly use holotanks on their starships, and they are plentiful in High Charity as well. AIs can also access the map data from the holotank's link to the Covenant information network and give directions verbally to anyone near the holotank. During the Battle of High Charity, Cortana entered one to aid John-117's passage through the city, remaining there long after the space station was transformed into a Flood hive. The Covenant also utilize portable holo-pedestals, to communicate over distance or in the battlefield. The Luminaries mounted on Covenant ships are typically linked to the bridge's holotank, which can display the information detected by the Luminary.^[2]

Gallery

Cortana displayed on the Pillar of Autumn's holotank.
A holotank in Dr. Halsey's lab underneath SWORD Base.
A large UNSC holographic table.
The Spirit of Fire's holotank displaying the Covenant shield on Arcadia.
Spirit of Fire's holotank displaying a diagram of Shield 0459.
A portable Covenant holo-pedestal displaying a hologram of the Prophet of Truth.
Ardent Prayer's holotank displaying the planet Reach.
Carter-A259 using another type of holographic display during a mission briefing.
A holotank in Cairo Station's Firing Control.
A Covenant holotank in High Charity displaying Cortana's avatar.
Andrew Del Rio looking at a holotank displaying a schematic of the UNSC Infinity.
Render of Cortana's holotank plinth in the Forward Unto Dawn in Halo 4.
Cortana's holo-sphere in the cryo-bay of the Forward Unto Dawn.
Cortana rising above her holotank in Halo 4: Forward Unto Dawn.
A disk-shaped holotank levitating inside a D79-TC Pelican.