Installation 01

Installation 01 is one of the Seven Halo Rings. Very little is known about it but it appears to have a moon-like landscape.

In 2552, during the Battle of Installation 05, a signal was sent to this Halo from Installation 05, putting it on standby mode. A readout from Installation 05's Control Room showed that Installation 01 was fully prepared to fire on demand.

A more comprehensive readout was later observed on the Ark during the Battle of the Ark by the Arbiter, Master Chief and the Prophet of Truth. It once again displayed that Installation 01 was in standby mode, being prepared to receive the signal to fire. However, the Master Chief deactivated the installation before it could be fired.

Trivia

 * The surface looks very moon-like, similar to a barren desert.
 * No water surfaces can be seen or have not yet been detected.
 * The surface resembles that of the surface of Mars (in fact, the surface is a picture of Mars' surface), though it has not yet been confirmed what kind of surface it is. More examinations will be needed to confirm the surface's components.
 * This ring is often mistaken for Installation 07 because of the order of the rings in the level "The Covenant", although this is not true because Installation 05 is the 5th ring from the platform on which Truth and the brutes reside rather than the direction in which the player enters the area. The 5th ring from the entrance has a volcanic surface, and this one obviously does not as Delta Halo had an identical surface to Installation 04.
 * This ring is believed to be furthest from the Ark, while Installation 07 is the closet, since they are probably numbered from their position closest to the Ark.