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 07 was fully prepared to fire on demand.
A more comprehensive readout was later observed in the Ark during the Battle of the Ark by Thel 'Vadam, John-117 and the Prophet of Truth, once again displaying that Installation 07 was on standby mode, waiting to receive the signal to fire. However, SPARTAN-117 deactivated the installation before it could be fired.
Installation 07 was the Halo that was in possession of 05-032 Mendicant Bias when it was stolen from the Forerunners. The Installation made its first appearance in Cryptum above the two San 'Shyuum Quarantine worlds and was used to eradicate the rebelling populaces whereupon the two humans Chakas and Riser were deposited on the surface of the ring world after being torn from the ship of their Forerunner companions Bornstellar and The Didact who were dropped to the besieged world below. Its diameter was originally 30,000 km as the other six rings that survived the Forerunner-Flood War, but was nearly destroyed after a failsafe collision course orbit with a Failsafe Planet, which reduced its diameter to 10,000 km. This was enacted by rogue Lifeworkers and presumably the Master Builder in order to stop 05-032 Mendicant Bias, in the event they failed or finished finding a cure for the Flood on the ring, in any genetic memories or observed immunities of humans. Thus, 05-032 Mendicant Bias enacted a plan to save the ring for the eventual use of destroying the Forerunners. Once 05-032 Mendicant Bias was eventually defeated in his plan, the Didact, out to save the life on the ring, ejected damaged sections of the Halo to reduce its size and allow it to pass through a small portal, which lead to the Lesser Ark. This was necessary due to Installation 07's severely drained power supply. At the command of the Didact, this Halo was sent through the portal after repairs were made one last time, holding the (presumably) Flood infected Forerunners processed by The Composer, the timelocked Graveminds (of which approximately ten had already developed), as well as any remaining species infected or otherwise; to remain untouched as a sacred tomb "to millions" for approximately the next one hundred and one thousand years.
- This ring is often confused with Installation 01 because it is the first ring from the entrance to the Citadel. Although, it is in fact the furthest ring from the Ark's control terminal and is the last ring to have its hologram light up during the activation sequence
- Like all Halo Arrays, Installation 07 gets its power from the Power Rooms which are connected to other Power Rooms placed around the whole ring. A power room on Installation 04 featured a large vertical Core and a dome-shaped roof, with large glass windows that run down the side. The energy which powers the Installation can be seen pulsating up through the core and then back down through the windows.
- The monitor of Installation 07 has the same numbers as Spartan-117, and it also has a reference to Bungies love for the number 7 (7^6 = 117649).
- It is supposed that this installation is actually a place infested by the Flood, and its surface should be affected and covered by a slimmy-tan colored mass they produce on the land (as seen in Halo: CEA terminal"343 Guilty Spark"). The yellowish surface of the ring supports this; it is possible that the Flood may have escaped quarantine on this ring, as it appears to be a surprisingly common event.
List of appearancesEdit