Self-destruct

There is more information available on this subject at Self-destruct on the English Wikipedia.

Cortana starts the countdown for the self-destruct as John-117 looks on aboard the UNSC Pillar of Autumn.

The self-destruct, also referred to as a scuttling sometimes in ships, is the explosive self-destruction of an object or vessel.

Overview

In the UNSC, the self-destruct is often an integrated mechanism present in starships and UNSC military bases and is used to cause a massive explosion to completely destroy itself in order to prevent vital navigational data and strategically-valuable information from falling into enemy Covenant clutches, as per paragraph five of the Cole Protocol. Self-destructs can take the form of reactor overloads or, alternatively, an explosive device to be detonated, usually an octanitrocubane charge or a nuclear weapon.

According to rumors, ONI installations would self-destruct if they couldn't confirm that the installation's authorized keeper was still alive.

Self-destruct mechanisms are also employed by the Covenant and their remnants in their ships, citadels and outposts. The Covenant were known to use a self-destruct to keep themselves from being captured in the event of a boarding action or as a method to get rid of boarders.

Forerunner installations employ self-destruct mechanisms as well. In the case of Requiem, the shield world's self-destruct resulted in the Epoloch system's star going supernova as well. In the case of Gyre 11, the ring was programmed to enter a course e which would result in a collision with a planet in several days.

While more informal, boarding parties have occasionally triggered a vessel to self-destruct by rigging a reactor overload or causing the engines to overheat such as Argent Moon and Ghost of Gbraakon.

The prowler UNSC Bad Moon Rising was prepared to use a hard self-destruct sequence if 343 Guilty Spark tried to take over the ship as he did the UNSC Rubicon.

Examples

Banished

Ghost of Gbraakon

After Pelican Echo 216 was captured by the Banished warship Ghost of Gbraakon, with Fernando Esparza and John-117 on it, the Master Chief scuttled the Banished dreadnought by destroying both cooling manifolds on the ship's bridge and then overheating the engines.

Covenant

Radiant Arrow

During the Skirmish over Netherop, the Shipmaster of the Covenant frigate Radiant Arrow activated the ship's self-destruct after it was boarded by SPARTAN-II Blue, Green and Gold Teams. The Shipmaster depressed a dead man's switch in order to give his crew time to abandon ship before detonating it. As the rest of the Spartans fled the ship, John-117 attempted to stop as many of the crew from escaping as possible. With his last breath, the Shipmaster released the dead man's switch, causing the Radiant Arrow to explode. However, John was able to escape using one of the ship's escape pods and only the Radiant Arrow's crew died in the explosion.

Retribution's Thunder

After discovering the Rubble, the Covenant destroyer Retribution's Thunder was betrayed and attacked by the Kig-Yar vessel A Psalm Every Day who wanted to take credit for the discovery themselves. With the ship disabled, Shipmaster Thel 'Vadamee ordered the self-destruct activated, killing the boarders. However, Thel and most of his bridge crew survived and were captured and taken to the Rubble.

Resplendent Fervor

After the CAS-class assault carrier Resplendent Fervor was cut in two during Operation: WARM BLANKET, the discarded rear half was set to self-destruct in an attempt to kill the Spartans attempting to rescue Dr. Catherine Halsey. However, the Spartans and Halsey successfully managed to escape from the explosion.

High Charity

In order to buy time to reach and fire Installation 08, Cortana instructed John-117 to destroy High Charity. The Master Chief destroyed the reactor pylons, triggering an overload of the city's backup reactor core. The Master Chief and Thel 'Vadam escaped in a crashed Pelican dropship as High Charity was destroyed by the resulting explosions, with only its broken outer shell and Unbreakable Spine remaining as burnt rubble. The Gravemind managed to escape, and immediately began rebuilding itself on Installation 08.

Pious Inquisitor

During the Skirmish on Pious Inquisitor, with the humans having killed several of Chol Von's crew and bearing down on the bridge, Von ordered Ril to detonate the ship's plasma torpedo reserves, choosing to destroy Pious Inquisitor over leaving it to the humans. As Chol and her team attempted to leave the bridge, the Spartan-II, Naomi-010, entered the bridge and killed Noit. Von and Bakz were able to flee from the Spartan. She and her remaining crew then made their way to a shuttle bay in order to escape. Kilo-Five wa