Space mine

Space mines, or naval mines are a class of naval weaponry employed by warships of the United Nations Space Command and Covenant. They function similarly to ground landmines, though are generally deployed in space to ward off the passage of other spacecraft.

Human space mines
For humanity, naval mines are a standard fitting aboard most warships of the CMA Navy and UNSC Navy. These weapons take the form of emplaced weapons that remain inert until a target passes within prxomity of them and activates their proximity sensors. Once triggered, the mine goes into standby and passively interrogates the target - if the critera for engagement is met, the mine will enter active status and engage its IFF beacon to avoid accidents and ensure that its detonation is done within legal limits established by the Unified Earth Government.

There are two known major naval mines in service within the UNSC Navy; the M1011 Moray and the M441 Hornet. The former of the two is a conventional explosive employed aboard smaller warships and larger strikecraft, including the and various iterations of the GA-TL1 Longsword. By contrast, the Hornet is a 30 megaton nuclear explosive employed aboard the much larger s, for use in seeding orbital space against capital ships. The use of nuclear mines aboard prowlers is a gambit for the captain of the vessel, as emerging from slipspace with the mines aboard risks emitting a burst of Čerenkov radiation - resulting in a captain having to weigh up whether to drop the mines into slipspace before emerging, or to risk detection.

Space mines can be useful in an ongoing space battle, as they can be deployed into the vector of an enemy fleet while they are distracted in combat. During the Onyx Conflict, used this to great effect to destroy a number of Covenant starship and prolong the survival of Admiral Carl Patterson's battlegroup.

Covenant space mines
The Covenant do not appear to place as heavy an emphasis on naval mines as humanity. However, they do have natively-developed space mine systems utilising antimatter as an explosive, similar in nature to Covenant antimatter charges. Several low-yield antimatter mines were used by the Mayhem during Operation: FAR STORM in 2555 to destroy a number of hostile Retriever Sentinels over Installation 00.

The Covenant are also capable of using plasma torpedoes for the same purpose as a naval mine, deploying thousands of self-targeting plasma torpedoes to encircle a given world and shoot down any spacecraft which attempts to breach orbit.

Netherop mine shell
In order to prevent rogue Fleetmaster Nizat 'Kvarosee from being rescued by the return of a loyal captain, the Silent Shadow had the Fleet of Swift Justice establish an orbital mine shell around Netherop which Nizat acknowledged was something that he himself would've done. Following the fleet's departure, Nizat witnessed the destruction of five vessels that were presumably trying to rescue him, ships that fell victim to the mine shell. The presence of the mine shell also kept the UNSC from being able to launch a rescue mission for Lieutenant Commander Amalea Petrov and her forces that had gotten stranded on the planet.

About a year after the Battle of Netherop, the UNSC sent a rescue mission. A Prowler sneaked into orbit and established contact with Petrov. However, the orbital mine shell destroyed both Pelicans that were sent to Netherop's surface. Not prepared to clear a full mine shell and unwilling twenty lives to save eight, the captain called off the mission, but he promised that a better-equipped mission would come back when it was feasible. True to the Prowler captain's word, the corvette came years later and worked to punch through the mine shell. On the third day, the Alpina made contact with the UNSC survivors and promised that a Pelican would collect them before the next evening, having apparently found a way through the mine shell. However, Nizat was able to use the Divine Hand to destroy the Alpina and the third rescue mission that came after it.

In November 2559, seeking a weapon that could destroy Cortana's Guardians, the Swords of Sanghelios visited Netherop. Arbiter Thel 'Vadam had high kaidon Olabisi Varo'dai coordinate an effort to dismantle the orbital mine shell in order to make it safe for his forces to land. Varo'dai's medium Covenant destroyer shepherded a swarm of Seraphs that flitted in and out of low orbit and used decoys and five-craft protective formations to laboriously clear out the mine shell. Observing the efforts to dismantle it, Thel was left wondering who had placed the shell around the planet in the first place. From their launching delay when a decoy passed one of the mines and their corkscrewing approach pattern, Thel was able to identify them as self-targeting s from early in the Human-Covenant War, but the Covenant World Registry made no mention of an orbital mine shell around Netherop, just the loss of the Radiant Arrow and the Steadfast Strike and that the Prophet of Truth had deemed the losses to be a sign of divine displeasure and forbade all Covenant vessels from entering the system. As observed by the Banished, by the time that the arrived, the Sangheili had spent three quarters of a cycle clearing out the mine shell and only needed another twenty units to finish the job. Once the orbital mine shell was finally cleared out, UNSC and Sangheili forces were able to descend to Netherop's surface, although the UNSC Pelicans were destroyed by Nizat with the Divine Hand.

With both the Created and the Banished closing in, Spartan Olympia Vale noted that the best that either the UNSC or the Sangheili could do was to reestablish the orbital mine shell in the hopes of securing the tel and its secrets until they had the strength to claim permanent possession.

After the Banished cleared out, the UNSC and Sangheili survivors were evacuated by an Owl to ten Condors in orbit. This included Petrov and her people that had been stranded beyond any hope of rescue for thirty-three years by the orbital mine shell and the Divine Hand. With the shell gone, Netherop was left open to outside access once again.

List of appearances

 * Halo: Ghosts of Onyx
 * Halo: Hunters in the Dark
 * Halo: Retribution
 * Halo: Oblivion
 * Halo: Outcasts