Installation 06

Installation 06, also known as Gamma Halo, is one of the seven Halo installations that survived Mendicant Bias' assault on the Forerunner capital.

Activation
In 2552, during the Battle of Installation 05, a signal was sent to this ring from Installation 05, putting it on standby mode. A readout from Installation 05's Control Room showed that Installation 06 was fully prepared to fire on demand.

Deactivation
A more comprehensive readout was later observed on the Ark, showing the inner section of the ring to be covered in what appears to be barren rock during the Battle of the Ark by Thel 'Vadam, John-117 and the High Prophet of Truth. It once again displayed that Installation 06 was on standby mode, waiting to receive the signal to fire. However, John-117 deactivated the Installation, and the others in the Halo Array before they could be fired.

Trivia
The surface seems to be similar to a rocky or moon-like terrain. The Halo Encyclopedia however states that it "appears to be a ring world covered in dense forest or jungle, similar to portions of Installations 04 and 05" but that "no recordings of its surface indicate any major water sources, so how this environment maintains viability remains unknown." This is further complicated by the Encyclopedia's basic description of the ring, which states that it has "tundra surface."