Installation 05


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Installation 05, or Delta Halo as it is called by humans, is one of the seven massive Halo fortress worlds built by the Forerunner. It was also the second Ring discovered by the humans.

Details
Planet of Orbit: Substance

Monitor: 2401 Penitent Tangent

Status: After Halo 3, unknown. The heavy damage done to The Ark could have put the Halo out of standby, or it could be unaware of the Ark's status, and still be awaiting remote activation. Its buildings seem to be more 'ancient' looking than Installation 04. The aging of it could be due to the damage the Flood has done to it as well as the battles that take place, hinting that this is where the majority or the most intense of the Forerunner/Flood battles took place. It is also possible that each Halo, while similar in architecture (i.e angular design, and same basic functional structures), has a different style from the next, an example being 05's Control Room having similarity to 04's Control Room in purpose, but with a new look, including a spherical shape at the center of the building. This is different than both versions of Installation 04, which look almost exactly the same (being of the same style), and have the same surroundings. However, a combination of this and the weathering caused by battles with the Flood could be why Delta Halo's structures look so dissimilar.

The Installation is also smaller than Alpha Halo, described as being the size of a moon, rather than a planet. Whether this size difference is common among Halo installations, or whether Installation 05 represents a different Halo Installation model to Installation 04, is unknown, but it is likely that since Installation 04 was made specificly to study the Flood and its size would help slow the spread of Flood incase of emergency may be a reason.

Its terrain, with the exception of the Quarantine Zone, are mostly lakes and jungle.

History
It is assumed that Installation 05 was built around the same time as Installation 04, around 98,665 BC. It was activated shortly thereafter by the Forerunners, killing all sentient life in the galaxy and, presumably, destroying the Flood as well, with the exception of those specimens kept in the Halos for research. As of 2552, it had a record of 1.2 trillion simulated firings and one actual activation.

Flood Disaster
Hundreds of thousands of years prior to 2552, the Flood on Installation 05 escaped and evaded containment. It is possible that another alien race stumbled on the Installation and accidentally opened its Flood Containment Facilities. The Flood quickly grew out of control around the area of the Installation's Library. The Flood were kept contained by a Sentinel Wall built around the Library, but 2401 Penitent Tangent was captured. Without it, the Sentinels of the Halo lacked a controlling intelligence and so many of the structures around Installation 05 fell into disrepair, and most of the Installation came to look like a jungle strewn with ruins. It's possible that a central Flood Brain Form became so massive that it reached sentience and became a Gravemind residing on the installation.

At the time of the Human-Covenant War, a Gravemind was holding 2401 Penitent Tangent captive. Even with the addition of Forerunner Sentinel Majors and Enforcers, the Flood were able to remain loose, albeit contained within the Quarantine Zone by the Sentinel Wall. This stalemate is believed to be the cause of the slow decline into disrepair of the structures of the Installation. The Gravemind itself resided in the chamber directly below the Index Chamber in the center of the Library.

Discovery
In 2552, the High Prophet of Regret, a Covenant hierarch, discovered the location of Installation 05 during The First Battle of Earth. He made a Slipspace jump from Earth to the Halo, followed closely by the Human ship UNSC In Amber Clad.



When they arrived Master Chief tracked down and killed Regret, just as the Covenant city of High Charity arrived with hundreds or thousands of ships. The Covenant landed on the Installation and foolishly deactivated the Sentinel Wall. Flood were able to infect much of the Human and Covenant forces, even taking control of the In Amber Clad and High Charity. The Covenant Arbiter retrieved the Index, believing it to be necessary to begin the Great Journey, but he was almost killed by the Brute Tartarus. He fell into the chamber of the Gravemind, where he met the Master Chief, 2401 Penitent Tangent, a Prophet form of Regret, and the Gravemind. There they "edified" him of the true nature of the Installation. Meanwhile, Tartarus brought the Index to the Halo's Control Room. Starting The Battle for Delta Halo's Control Room. He activated the station, but was killed before it could fire. The Index was removed from the chamber, but the installation had a fail-safe protocol which activated and sent a signal to the other Halos, putting them on standby mode, ready for remote activation through The Ark. When Installation 05 was last seen, Flood were running loose as well as in High Charity and the surrounding fleet. The Flood appear to be in control of the Installation, as the Civil War of the Covenant has caused fighting between the remaining Covenant forces on the ring. The extent of the flood control in Delta Halo after Halo 3 is unknown, since they were never eradicated. With the Gravemind killed at the end of Halo 3, it is most likely that the Flood reverted to their original feral and disorganized state, and would be easily controlled by the Sentinels and Covenant forces present there although it is not for sure due to the unknown fate of 2401 Penitant Tangent. The UNSC AI Cortana had suggested that the Installation be destroyed via the use of a NOVA Bomb, but it is unknown if the idea was ever followed.

Astronomy
See full article: The Halos

The "Ringworld" of Halo is much smaller than Larry Niven's Ringworld, by a magnitude of 3,000. While the diameter of Niven's ringworld is close to the diameter of Earth's orbital of 300,000,000 km, the 10,000 km diameter of Halo is much closer to the diameter of Earth itself, which is 12,756 km. Ringworld has a star similar to our sun in its center, and Halo is orbiting a planet, but does not encircle it.