Sentinel manufacturing facility



Sentinel Constructor Factories are facilities that manufacture various types of Forerunner automatons, such as Sentinels, Sentinel Majors and Enforcers, or in case of Onyx, Onyx Sentinels. The appearances and sizes of these facilities vary greatly depending on their location.

Overview
There are several varieties of Sentinel factory. The most commonly seen are massive, floating structures that hover above battlefields. These facilities were used during the Flood outbreak on Installation 05, and could be seen in the sky above the Quarantine Zone around the Installation's Library.

Onyx contained a massive Sentinel factory located underneath its north pole, which produced the huge number of specialized Onyx Sentinels that made up the artificial planet's superstructure. The Sentinels in this facility were constructed out of molten ore spewed from a massive machine, which cascaded into a hollow tower. From the bottom of this tower tumbled millions of Sentinel components, which then were ferried to another part of the factory by energy beams. As they traveled, they assembled themselves into the three-meter long "booms" of the Onyx Sentinels. In the center room, there was a pyramid-shaped structure described as being "five times the height of the Great Pyramid of Giza", which was composed of the "eye" spheres of the Sentinels. Every six seconds a sphere from the apex of the pyramid ascended in a shaft of silver light. When the spheres emerged, they had been assembled into a complete Onyx Sentinel.

Another Shield World - type installation discovered by the crew of the UNSC Spirit of Fire had several types of underground Sentinel factories, which created standard Sentinels, Super Sentinels and Protectors.

Halo 2
These facilities float high above the ground, in an attempt to keep them somewhat safe from the majority of Flood if there is ever another major outbreak amid the Installation.

During Halo 2, they first appear in the level "Sacred Icon" when the Arbiter reaches the inner corridors of the Sentinel Wall.

There is an opening cleft in the structure that is similar to the opening where he first entered from the Phantom. In the distance, above the Library, there are two large floating objects. Once the Arbiter exits the wall, one of these objects is hit with a few Plasma Mortar shots (possibly fired from a Flood captured Wraith to slow down the Forerunner defenses) which then crashes down to the ground.

In the next level, you would be able to observe the same crashed structure being pounded by Wraiths and Scorpions and fight through it as Sentinels and Flood fight each other.

Onyx
Within the artificial planet Onyx, there was a Sentinel Production Facility which constructed Onyx Sentinels. This facility produced a new Sentinel every six seconds, quickly making enough Sentinels to combat any known threat. It was later destroyed by the Spartan-II's and III's to halt the production of Sentinels on Onyx.

The facility was vastly different from the ones seen on Delta Halo, being a massive underground room under Onyx's northern polar region. The facility was described as being so large that the arc of the planet's curve could be seen in the distance. Clouds of Onyx Sentinels hovered over the construction facility.

Halo Wars
In Halo Wars, there are Sentinel Factories but they are grounded, fixed structures where players are able to construct Sentinels, Super Sentinels or Protector Sentinels.