Installation 08

"A replacement, for the ring you destroyed."

- The Arbiter observing the second Installation 04's construction alongside John-117.

The replacement for Installation 04 was a partially completed Halo Ring which began construction at the Ark after the destruction of the original Installation 04.

Background
This Installation was designed as a similar (if not identical) replacement to the previous Installation 04 in order to ensure that the Forerunner's Halo Network was intact, and therefore able to encompass the entire Milky Way galaxy.

Creation


Following the Battle of Installation 04 and its subsequent destruction, the Ark was notified, and an automated function began building a new replacement for the missing Installation's position.

The main weapon was built first with the surrounding circular metal structure after it. It is unclear how the Ark was able to create the new installation or what the source of raw materials for its construction was, as no insight is given to those functions of Installation 00. It is possible, though, that the materials came from the Ark's Core, a planetoid located at the center of Installation 00, as the core seems to have large areas torn away from the surface and is also located at the center of the Ark's foundry, where this ring was built.

Before it was released into space (presumably work was to finish there before being sent to Threshold to replace the original Installation 04 destroyed at the end of Halo: Combat Evolved) the Installation has a number of primary features available even though it was still not complete, these included the environment, atmosphere and main structures and the main weapon, though the ring structure was not yet stable enough to survive this weapon's discharge.

The ring was also not connected to the other Installations, allowing a tactical pulse to be fired without triggering the other 6 Installations. It is never revealed if this is an option available to completed installations as well although it is likely Installation 04 (II) merely had not been set up with this network yet, as it was incomplete; a logical precaution considering the effects of a misfire.

It is also never revealed how the Installation was intended to be placed back in the galaxy in a position where it would complete the Halo rings' coverage of the galaxy. Slipspace travel is a possibility, but this would require a Slipspace rupture of a truly colossal scale and it is unknown if the Ark or Halo would contain the systems necessary to produce such a large rupture. It is thought that since the storm over Earth before the Portal to the Ark was activated was similar to the storm over Threshold shortly after the original Installation 04 was destroyed, that there was a portal to and from the Ark on or near Threshold. This, however, is not confirmed.

Discovery
The new Installation was released into space just above the Ark, but it was still incomplete then. The Master Chief and the Arbiter decided that the only way to stop the local Flood infestation (which included the Gravemind from Installation 05) was to fire the incomplete Installation, which was out of range of the other rings.

The Chief headed to the Flood-controlled High Charity to retrieve Cortana, as she held the Activation Index from the first Installation 04.

After retrieving Cortana, during his flight from High Charity, the Chief destroyed the main reactor core (at Cortana's suggestion). This greatly damaged, but did not destroy, the Gravemind. Aided in his escape by the Arbiter, the Chief found a crashed Pelican on the exterior of High Charity and piloted it to the Control Room.

The Pelican crashed in a snowy valley near the Control Room, which was situated atop a high tower (as was the original Installation 04's). As the Chief and Arbiter made their way towards the tower, Flood dispersal pods descended from the sky and the Gravemind revealed that he was not yet defeated.

After battling to the top of the tower, aided by Sergeant Major Avery Johnson and his Spartan Laser, the team reunited with Guilty Spark.

Destruction
As they entered the Control Room, Spark stated that "this Installation would be ready to fire in just a few more days", and that "a premature firing would destroy the Ark," and the ring. However, due to the gravity of the situation, Johnson replied curtly "we don't have a few more days," and attempted to unite Cortana with the Control Core.

This was too much for 343 Guilty Spark, who regarded the Installation as his. He entered full Rampancy, (or he could have just been carrying out his original programming, which would have been to ensure the safety of Installation 04) and fired on Johnson with his enhanced Sentinel Beam, mortally wounding him.

The Chief rushed to Johnson's aid, but was knocked down by Spark's beam, which was then turned on the Arbiter, who was knocked out of the door, which closed. As Chief tried to get up, he was fired upon again. However, his shield took most of the blast. In the ensuing battle, when the Chief was cornered, Johnson fired his Spartan Laser on Spark before lapsing into unconsciousness; this stunned Spark. Johnson gave the Laser to the Chief with the words "Kick his ass." After three shots from the Laser, Spark exploded and the Chief was finally able to unite Cortana and the Core.

As Spark predicted, the ring was not ready to fire, and it began to shake itself apart and disintegrate. Master Chief attempted to save Johnson, but he replied with only "Send me out... with a bang." before closing his eyes. Master Chief and the Arbiter escaped through the first Phase Pulse Generator room and then to Johnson's Warthog. The vibration of the activation began to tear the Installation apart, causing explosive reactions all across incomplete sections of the installation. Master Chief and the Arbiter barely managed to reach the UNSC Forward Unto Dawn before the ring detonated. Cortana stated that the ring's explosion "did a number on The Ark."

Trivia

 * In the Control Room, the hologram of planet Threshold is missing and if the control room is viewed from above, it looks like an entirely black circle. If Threshold was present, it would have a blue center. This draws parallel to a glyph during the Iris campaign, which was missing the circle in its center compared to all the others.
 * The map Avalanche from the Legendary Map Pack takes place on Installation 04 (II). Note, the Ark and the Milky Way are missing from the sky background graphics.
 * This Installation would have had a Flood Containment Facility, just like the first Installation 04, although there would be no Flood to be transported to them at that time.
 * Unlike the first game, the first Phase Pulse Generator room is now accessible via a small path, instead of only by aircraft.
 * It is very possible that if the Ark survived the explosion from this Installation that it would be making a third one which may be in later games or books.