Shiva-class nuclear missile

The Shiva-class nuclear missile is a UNSC ship-mounted thermonuclear weapon, outfitted with a varying payload of up to 750 gigatons.

Background
The Shiva Nuclear Missile, is a nuclear ordnance often but not always employed by the UNSC in ship to ship engagements with the Covenant. The use of nuclear weapons such as the Shiva, are only used when both UNSC forces are outnumbered, or tactical situations that demand the use of such. The UNSC will also often try to use nukes only when they can be sure casualties on their forces will be minimum.

Used on all warships in the UNSC including Capital ships, the Shiva is stored in a ships nuclear storage bay until it is time to be deployed, depending on the launch method, it can be loaded into a ships launch tube and launched on a small missile, somewhat in size to the modern day Trident missile. Once launched from the ship, its on board guidance system can guide the warhead to its intended target, however the warhead's course can be corrected mid-flight by the ships navigation officer or A.I. The warhead can also be fitted on C709 Longsword Interceptors for a low-profile insertion. The Shiva can be detonated by two methods, radio transmission code sequence, or a proximity fuse, whatever method is most effective for the situation. Space based nukes are preferred in combat situations with the Covenant because of the massive Electromagnetic Pulse or EMP, release by such warheads like the Shiva, this is most effective for disabling electronics aboard nearby enemy ships.

It should be noted that Covenant Capital ship shields have enough power to absorb a full thermonuclear blast from far away, but not directly. If the warhead detonates inside the shield, the effects of the blast is multiplied tremendously, due to the ship's shields containing the blast. This is demonstrated in the Battle of Reach by Captain Keyes while piloting the Pillar of Autumn. However, it should also be noted that because of the varying payloads, a lighter warhead may not be able to eliminate a covenant's shields even from close range.

Trivia

 * Shiva is the name of the Hindu god of both disaster and peace, who would destroy the world in order for it to be recreated.