Installation 02

Installation 02, also known as Epsilon Halo, is one of the seven ring-shaped superweapons that comprise the Forerunners' Halo Array. Located in the Norma Arm on the near-opposite side of the Milky Way galaxy from Installation 04, Installation 02 features a water-based environment with rocky outcroppings and large ice floes.

Construction and early history
The Forerunners had Installation 02 constructed by the Foundry of Installation 00 approximately around the same time as the rest of the Halo Array, circa 97,445 BCE during the Forerunner-Flood war. The array was designed by the Forerunner Builders to combat the parasitic Flood by eradicating them and all sentient life in the Milky Way. After the rings were built, Installation 02 and its fellow Halos were distributed from Installation 00 to positions across the galaxy through slipstream space portals.

Afterwards, the Halo Array was fired and eradicated all sentient life from the galaxy. The Forerunners proceeded to reseed the galaxy with life from the species that were preserved on the Halo installations. Like its fellow installations, Installation 02 became home to dormant specimens of the Flood that were intended to be used to help find a cure to the parasite in the future. With the Flood defeated, the surviving Forerunners exiled themselves from the galaxy.

Human-Covenant War
"Fail-safe protocol: In the event of unexpected shutdown, the entire system will move to standby status. All remaining platforms are now ready for remote activation."

- 343 Guilty Spark, after the Halo Array is placed into standby mode

On November 3, 2552, during the Battle of Installation 05, Chieftain Tartarus of the Covenant activated Installation 05, though United Nations Space Command and Sangheili forces managed to terminate the firing sequence before the Halo could fire. As per fail-safe protocol in the event of an unexpected shutdown, a signal was sent to Installation 02 and the rest of the Halos from Installation 05, placing all Halos of the array on standby mode, ready for remote activation from Installation 00. A readout from Installation 05's control room showed that Installation 02 was fully prepared to fire on demand.

However, during the Battle of Installation 00 on December 11, 2552, the UNSC and allied Sangheili forces fought to prevent the Covenant from firing the Halo Array from the Ark, as Installation 02 and its fellow Halos were still in standby mode and was prepared to receive the signal to fire. Eventually, Master Chief Petty Officer John-117 succeeded in deactivating Installation 02, as well as the rest of the array, before it could be fired.

Post-Covenant War
In March of 2555, monitor 000 Tragic Solitude of Installation 00 utilized a captured human to activate the Halo Array's firing sequence, triggering a countdown set for the Halos firing in five weeks from March 8, 2555. After discovering the countdown on Installation 07, the UNSC and Swords of Sanghelios launched a joint operation to Installation 00 in which a team destroyed Tragic Solitude and ended the Halo Array's firing sequence.

Description
Like its fellow ring installations of the Halo Array, Installation 02 is approximately 10,000 kilometers (6,200 miles) in diameter and has a surface width of 318 kilometers (198 miles). Installation 02's environment is comprised of large oceans with outcroppings of rock, as well as far-reaching ice floes. The installation was capable of wiping out all sentient life in a 25,000 light-year range, along with its fellow Halo installations.

Trivia
The surface of this installation, as depicted in Halo 3, is similar in appearance Ganymede's surface.

List of appearances

 * Halo 2
 * Halo 3
 * Halo Legends
 * Origins
 * Halo: Combat Evolved Anniversary
 * Terminals
 * Halo 2: Anniversary
 * Terminals
 * Halo: Hunters in the Dark