NOVA Bomb (Sith'ari)

"This is the prototype NOVA Bomb, nine fusion warheads encased in lithium triteride armor. When detonated, it compresses its fusionable material to neutron-star density, boosting the thermonuclear yield a hundredfold. I am Vice Admiral Danforth Whitcomb, temporarily in command of the UNSC military base Reach. To the Covenant uglies that might be listening, you have a few seconds to pray to your damned heathen gods. You all have a nice day in hell..."

- Vice Admiral Danforth Whitcomb's recording on the NOVA Bomb that detonated outside of Joyous Exultation

The NOVA Bomb is a United Nations Space Command weapon created from the combination of multiple nuclear warheads. At maximum power, it possesses the ability to render an entire Earth-sized planets lifeless.

Design and Mechanism
The bomb consists of nine hafnium-based nuclear fusion warheads encased in an ultra-dense shell of classified compostion. When detonated, the shell compresses and traps the blast of the warheads for a few fractions of a second, intensifying the blast and boosting the yield by approximately one hundred times. At maximum power, the device has a yield of approximately forty seven thousand megatons.

Each warhead has a yield of approximately 52.2 megatons and utilises the Induced Gamma Emission of hafnium's isomer 178m2 to produce the explosion. The exact amount of hafnium-178m2 contained in each warhead remains classified, but given the isomer's nature, is considerably less than the amount of uranium required to produce a similar blast in a conventional nuclear warhead.

During detonation, the hafnium-178m2 in each warhead is irradiated with a carefully tuned blast of X-rays at a classified frequency. This induces the hafnium to release all its stored energy in the form of an explosive blast of Gamma Rays. To further damage the target planet's ecosystem, the bomb is heavily salted with cobalt.

All these factors give the NOVA Bomb an unprecedented payload for its size. Its capability to destroy all life a planet has earned it the nickname "Planet-Killer". It should be noted that in one recorded event when a NOVA Bomb was detonated in the midst of a fleet close to a planet, it scorched one quarter of the planet's surface due to a concentration of thermal energy inside the planet's atmosphere; it also shattered a moon. It is the most destructive weapon in the UNSC's arsenal, and due to its status as a weapon of mass destruction, it is only deployed under very special circumstances.

History and deployment
First designed during the Human-Covenant War by the UNSC, it was intended for the NOVA Bomb to be used in space against Covenant fleets in an attempt to nullify the Covenant's enormous numerical and technological advantage. One was used to destroy the planet Minorca during the Covenant invasion in 2551. During the Battle of Reach, however, a number of bombs were left on Reach and "repurposed" by Admiral Danforth Whitcomb. He activated it and set the timer for ten days. His reasoning was that "either the Covenant pack those bombs up and take them home for study, a possibility that I hope to God happens. A bomb like that could crack their homeworld in two. Or, the bombs stay here and they'll stop the Covenant on Reach..." This NOVA Bomb ended up on the Covenant Carrier Sublime Transcendence and was accidentally detonated by a group of Huragok stationed aboard the Carrier. Immediately after Kwassass, a fellow crew member, deciphered Admiral Whitcomb's message, the Huragok, through their curiosity and frenzied obsession, fixed the circuitry of the bomb, detonating it despite Kwassass's attempts to stop them. The Huragok completed the detonation timer's circuit, which promptly resulted in its activation. The resulting explosion occurred between a Covenant outpost planet Joyous Exultation and its moon, Malhiem, scorching half of the planet and shattering the moon. The resulting winds on Joyous Exultation flattened cities and spawned tidal waves. Radiation flooded the planet and killed everything, penetrating the surface of the planet to its core. The NOVA Bomb explosion severely damaged three-quarters of the fleet that was there, totaling over 300 ships. Eighteen Destroyers, two Cruisers, one Carrier and the Flagship Incorruptible escaped the NOVA Bomb explosion due to a Slipspace jump en masse just seconds prior to the explosion. Other ships arrived to reinforce the Incorruptible arrived from Joyous Exultation later, suggesting that they escaped the bomb's detonation as a result of being positioned on the opposite side of the planet. The novel describes the explosion as though "a small star erupted between Joyous Exultation and its moon."

During the Battle of Installation 05, and the subsequent quarantine of the Installation and High Charity, the A.I Cortana requested that UNSC HIGHCOM deploy a NOVA Bomb around Installation 05 and High Charity to stop the outbreak of the Flood. This request was not granted due to the low number of warheads left and their need to protect the Inner Colonies. High Charity was not bombed and later landed on Installation 00. The Sangheili later glassed the surface of the ring to destroy the Flood. The Sangheili never discovered what exactly had taken place at Joyous Exultation. They reasoned that a Jiralhanae fleet had utterly destroyed Xytan Jar 'Wattinree's fleet and glassed the planet. The United Earth Government, however, realised exactly what had happened after hearing the Sangheili's account but chose to keep the information secret, knowing the terrible effect the information would have on the UEG/Sangheili alliance.

NOVA Bombs were deployed, albeit sparingly, during the War of Vengeance. The one-time capital of the Blood Covenant, Pious Ascension, was rendered utterly lifeless by a NOVA launched from a UNSC Prowler. The UEG had several reasons for deploying the bomb: other than totally destroying Pious Ascension, they scored a massive psychological blow to the Blood Covenant, showing them that they had a weapon of incredible power to which the Blood Covenant had no analogue. It also served the purpose of strengthening their alliance with the Sangheili Armed Forces, demonstrating to the SAF that the UEG could very easily destroy them if it so desired.