Nuclear weapon

There is more information available on this subject at Nuclear weapon on the English Wikipedia.

An atomic blast.

A nuclear weapon is a type of ordnance using nuclear fission and/or fusion as a source of energy. The yield of a nuclear weapon is measured in the amount of tons of "TNT" needed to generate an explosion of similar proportions.

Overview

Nuclear weapons are commonplace in the United Nations Space Command's arsenal and in select civilian uses. The UNSC uses nuclear weapons to great effect in space warfare, increasing their effectiveness with special payloads enhanced for vacuum use. Throughout the Insurrection and early on in the Human-Covenant War, space-borne UNSC nuclear weapons used proximity-fused warheads that relied on the detonation's direct radiation and thermal shock, which quickly proved ineffective against Covenant warships' energy shielding. As a result, the UNSC developed new types of warheads sporting nuclear-pumped X-ray lasers and Casaba Howitzer-type shaped-charge warheads known as "Spears", which focus the nuclear blast into a directed, relativistic plasma jet. Conventional nuclear weapons are still used in planetary warfare as tools of last resort. Some planetary nuclear weapons also have shaped-charge properties, such as the Mark 2550 Havok MFDD, a bunker buster warhead designed to direct its blast against underground targets.

Commonly, the casings of UNSC nuclear weapons such as the FENRIS nuclear warheads are heavily reinforced, both to contain radiation and to boost the thermonuclear yield for containing the detonation for a split second longer. The hardened cases also protect the nukes inside and prevent them from going off accidentally - it was noted that detonating a bomb next to a FENRIS warhead would barely scratch the casing. There are various grades for the types of nuclear weapons. An example is the excavation-grade HAVOK tactical nuclear weapon. While presumably not as powerful as a military-grade weapon, a single warhead is described as being powerful enough to turn Ivanoff Station "into a piñata" and was powerful enough to destroy Mantle's Approach and the Composer when detonated on the inside of the ship.

Nuclear weapons are also sold commercially, and are commonly used in asteroid mining. In 2511, an Insurrectionist suicide bomber used one such commercial explosive in a terrorist attack on the Haven arcology on Mamore, killing two million and injuring over eight million more.

An operational idiosyncrasy of nuclear weapons is the result of containing fissile material. Fissile materials, such as plutonium, emit a readily detectable Čerenkov radiation signature upon exiting slipspace that negates stealth measures. As a result, if complete stealth is required, prowlers are forced to jettison any on-board nuclear weapons before transitioning back to normal space to avoid detection. In addition, nukes launched from slipspace can easily be detected by enemy sensors, despite the use of stealth coatings or lead linings.

The energy shielding used in Covenant warships has been noted to dampen the electromagnetic pulse generated by the detonation of a nuke inside the ship. The SPARTAN-IIs used this to their advantage when they destroyed a Covenant cruiser during the Fall of Reach, without risking damaging the nearby orbital defense generators.

If nuclear arsenals are not available, especially during a situation where NOBLE Team needed one to destroy a Sh'wada-pattern supercarrier, one alternative is to use a Slipspace Drive in lieu of nuclear weaponry.

History

Nuclear weapons carried by a GA-TL1 Longsword.

The first space-borne nuclear weapons were used during the Interplanetary War in the 22nd century. However, they were not considered a viable weapon of space warfare for the next several hundred years; at the time of the start of the Insurrection in 2494 it was widely believed that fissile detonations in space were practically useless, as the vacuum of space severely reduces the explosive yield and the resulting electromagnetic pulse. As such, it came as a surprise to the UNSC when the Insurrectionists used a nuclear device in a space battle following the Callisto Incident, having hidden it in an asteroid in advance. When detonated, the nuke shattered the asteroid to molten pieces, which in turn destroyed one UNSC ship and severely damaged two more. The Jiralhanae used nuclear weapons during their global civil war to such a degree that it set their species back hundreds of years.

Engagements against the Covenant during the Human-Covenant War quickly proved conventional nuclear weapons' ineffectiveness against Covenant warships' shields, forcing the UNSC to develop more effective payloads. The frequent deployment of nuclear weapons in space engagements constantly kept the UNSC's nuclear stockpiles near depletion. This occasionally forced them to resort to using obsolete nukes or unorthodox solutions.

The Covenant did not generally use nuclear weapons, regarding them as "heretic" weapons. An exception to this were the Jiralhanae, who had no qualms about using captured UNSC nukes or any other UNSC matériel. However, following the end of the war, remnant groups of the Covenant have adopted more liberal policies in regards to human weaponry for practical reasons. Human-made nuclear weapons have subsequently fallen into the hands of Covenant terrorists and cultists.

UNSC nuclear ordnance

The nuclear mushroom cloud seen in the bombing of Nagasaki in World War II.

Small Fusion Destructive Devices

Small Fusion Destructive Devices (SFDDs) are the smallest category of UNSC tactical nuclear weapons and have a low yield. Only one such weapon is known:

• ERIS tactical nuclear weapon: a small portable nuke with a yield of ten kilotons.

Medium Fusion Destructive Devices

Medium Fusion Destructive Devices (MFDDs) are a rather inclusive category of portable tactical nuclear weapons, encompassing low destructive yields in the kiloton-megaton range. These weapons are used for both military and mining purposes, and are often contained in a cylindrical casing which can be affixed to a missile or detonated manually. MFDDs have a relatively simple and unimaginative operating architecture - consisting of a bare cylinder with a keypad. They were used during the Human-Covenant War by the UNSC as part of their fallback strategy, serving as territory denial for encroaching enemy forces or being used to destroy large concentrations of troop formations on worlds deemed unsalvageable.

Known MFDDs include:

• FENRIS nuclear warhead: a low-yield thermonuclear device, slated for decomissioning but brought back into service during the Covenant War due to high munitions expenditure.
• FURY tactical nuclear weapon: considered the closest thing to a "nuclear grenade", the Fury is a rugby ball-sized device with a yield of just under one megaton.
• HAVOK tactical nuclear weapon: a series of "clean" tactical nuclear weapons manufactured by Misriah Armory in over a dozen variants with a range of yields. Some Havok nukes may be used as nuclear landmines, or as warheads on strikecraft or starship-launched missiles.

Strategic and naval nuclear weapons

HORNET mine

Main article: HORNET mine

The HORNET is a 30 megaton space mine. The devices are designed to be more stealthy than an ordinary nuke and are carried aboard UNSC prowlers. Although like all nuclear weapons, they can be easily detected when exiting slipspace, they can be rendered practically undetectable by cooling them to near-absolute zero temperatures, same as that of interstellar space, in their launch chambers.

Nuclear Delivery Systems

Nuclear Delivery System is the formal term used by the UNSC to refer to its naval nuclear missiles, pairing a delivery vehicle with a separate, modualr warhead. The warheads are kept separate from the missile until they are specifically needed for combat, and may encompass a variety of specialised forms including "spear" nuclear shaped-charge warheads which use a fusion bomb to accelerate a plasma jet to relativistic velocities. Spear warheads use the kinetic force of the plasma jet as their damage mechanism, rather than the radiation or heat of the nuclear detonation.

Known nuclear missiles include:

• SHIVA-class nuclear missile: a versatile series of nuclear missiles carried aboard many ships and some bombers in the UNSC fleet.
• RUDRA-class nuclear missile: a nuclear missile that can be used by Sahara-class heavy prowlers. UNSC Port Stanley carried multiple "enhanced yield" Rudras in 2553.
• HARPOON-class nuclear missile: a large nuclear missile carried aboard the Paris-class heavy frigate.
• HYPERION-class nuclear missile: an extremely large nuclear missile carried aboard some UNSC frigates, used for attacking targets of strategic importance.

NOVA bomb

Main article: NOVA bomb

The NOVA is a strategic device designed under the purview of Vice Admiral Danforth Whitcomb, and undoubtedly humanity's most powerful weapon. It consists of nine nuclear warheads encased in a lithium triteride shell, which is compressed during detonation, boosting the yield "a hundred-fold". A single NOVA has enough power to cause complete devastation on a planetary scale, and can destroy orbiting moons and spacecraft.

To date, only two such bombs have ever been used: the first to destroy the Covenant colony of Joyous Exultation, and the second to destroy the colony of Glyke.

Gallery

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  An unidentified nuke used by Samuel-034 to destroy the Unrelenting in Halo: Fall of Reach.

List of appearances

Halo: The Fall of Reach (First appearance) Halo: The Flood Halo: First Strike Halo 2 Halo: Ghosts of Onyx Halo 3 Heroic Map Pack Halo: Contact Harvest Halo 3: ODST (Mentioned only) Halo: Legends Origins Halo: Evolutions - Essential Tales of the Halo Universe The Mona Lisa The Impossible Life and the Possible Death of Preston J. Cole Remember Reach Deliver Hope Halo: Reach (Mentioned only) Halo: Fall of Reach Covenant

Halo: Combat Evolved Anniversary Terminals Halo: The Thursday War Halo 4: Forward Unto Dawn Halo 4 Spartan Ops Halo: Escalation Halo: Nightfall Halo: Fractures Into the Fire (Mentioned only) Halo: Last Light Halo: Envoy Halo: Retribution Halo: Legacy of Onyx (Mentioned only) Halo: Silent Storm Halo: Battle Born (Mentioned only) Halo: Renegades Halo: Oblivion Halo: Edge of Dawn