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UNSC WARNING: This document, Solid Light Barrier, is property of the UNSC and is Classified [NOVEMBER BLACK], protected under Office of Naval Intelligence Security Protocol 1A. Disclosure of its contents to, or access or alteration by, personnel with a clearance level lower than GAMMA THREE is an offense punishable by court(s) martial and imprisonment or execution for treasonous acts. Failure to disclose confirmed or suspected breaches of security will be treated as complicity, and is punishable by dishonourable discharge and/or imprisonment.
Lieutenant Commander Michael Pomare, Office of Naval Intelligence, UNSCDF Navy
ONI Seal 1

Contrary to popular belief, the phrase "energy shields" does not refer to a single continuous line of development. While the electromagnetic fields used by Covenant infantry and SPARTAN-II MJOLNIR are effective, systems used by Forerunner technology and limited Covenant systems make use of a vastly different mechanism - solid light. A phase transition induces a state change in photons, resulting it the photons behaving like particles rather than as a wave, and creating solid and almost invisible plane. While UNSC technology has a very poor understanding of the systems, reverse-engineering has produced some significant results - the energy shields introduced on UNSC starships after 2553 use solid light barriers for defense, deemed appropriate given the Covenant's expansive knowledge of electromagnetic shields; even earlier, the MJOLNIR Mark IV/Vajra II V-II/B, V-II/D and V-II/E used solid light barriers for defense, though the technology for smaller-scale versions of the system were never perfected and were eventually discontinued by 2557.


When the Covenant attacked Harvest, the UNSC assembled the single largest space fleet it had assembled since the Interplanetary War to respond to a threat of such magnitude. There are several reasons for this: for one thing, the UNSC hoped that the sheer numbers of the fleet would force the ship to back down, and perhaps return the new alien civilization to the negotiating table - a futile effort. Mostly, however, it was because the alien ship, in wiping out Battlegroup Heracles, had demonstrated that it used advanced directed energy weapons and a potent energy shield system for defense. When Cole's fleet engaged the enemy warship engaged the ship, they lost thirteen ships before the fleet managed to lower the enemy ships shields and inflict significant damage to it.

From then on, the primary advantage the Covenant would possess was their energy shield technology. For the most part, their DEW systems were about as effective as UNSC shipborne weaponry, and their users certainly had an inferior understanding of their own weapons; likewise, the advantages Covenant ships enjoy in slipspace technology were largely ignored by their ship captains. The single most important advantage the Covenant enjoyed was virtual immunity from anything the UNSC could hurl at their ships. Tactics would eventually be found to penetrate or circumvent the shields, but their effectiveness could not be denied, and ONI tasked Project TEMERITY, a sub-section of Naval Special Weapons, to study captured systems and attempt to reverse-engineer them for UNSC use. The history of energy shield technology from then on becomes long and mixed. Project MJOLNIR would go on to develop powerful and efficient electromagnetic shields, able to repel bullets and debris, and capable of interfering with plasma weaponry, though the shields would only see use on the MJOLNIR Powered Assault Armor series. Others experimented with a mixture of superheated plasma held in place by a magnetic field, similar to Covenant weaponry, but creating a solid barrier rather than a hurtling projectile. But in the end, it was the Solid Light Barriers developed by Project TEMERITY that might be claimed to have had the largest impact on UNSC shield technology.

While most projects preferred to focus on recovering, studying and reverse-engineering Covenant equipment, the often poor quality of the equipment from battle damage hindered most investigations. TEMERITY instead chose to direct their attention to anomalous technology present on a number of worlds within UNSC space; besides being the primary target of almost every Covenant attack, the technology predated both the UNSC and Covenant by hundreds of thousands of years, and was still centuries more advanced. Recovering a number of relics from Covenant hands, TEMERITY made significant gains, some of them quite startling. Solid light is not a new theory, or even a new technology - it has been used in quantum computers since the early 23rd century. But the application of it on a larger scale was deemed an almost revolutionary development. In particular, they developed the SLB-77X, a prototype solid light barrier generator. Equipped to the UNSC corvette Raven, the barrier, a single pane of solid light, proved more than sufficient for reflecting debris, and proved effective against most DEW types. The SLB-78X would be six generators working in tandem to create a three-dimensional "box" around the Raven, effectively protecting the ship from all sides. The power requirements for the system proved enormous, impractically so, and it was not until advances were made in that area in 2542 that the system was deemed a viable alternative to the MJOLNIR-driven electromagnetic shields that still proved difficult and unwieldy. Rather than a solid box, the SLB-82X would create a layer of solid-light that closely hugged the external hull in a spherical field to reduce the ship's sensor signature and improve integrity, with small panes able to be deactivated in the barrier layer to allow hull-mounted weaponry, such as the 50mm CIWS system and Archer missile pods, to fire at enemy ships. In 2552, the introduction of the SLB-83A had begun with the first field prototypes installed in the Ajax-Class Heavy Frigates. Less than a handful of ships equipped with the systems would survive the Fall of Reach, and of these most were destroyed during the Battle of Earth, but the series would be revived in the form of the SLB-85C, introduced in 2554 and made standard on all post-war ship designs.

The Forerunners, an ancient and technologically advanced civilization that disappeared approximately one hundred millennia ago, seem to have used solid light barriers much more extensively than the Covenant, who reverse-engineered their technology to produce their own. Solid light barriers are standard issue on most installations and facilities, used for holographic control panels and displays, "light bridges", and defensive systems on Sentinel and Protector units, while Enforcers are the only known unit to use electromagnetic shields. The Covenant seem not to have adopted such systems except in rare circumstances, preferring to rely on electromagnetic versions for personal energy shields, portable emplacements and starship defense. The Prophets use solid light barriers to an extremely limited extent, but such systems are fragile and temporary, used in conjunction with limited portable translocation devices. Even after the collapse of the Covenant, other races have been slow to adopt solid light barriers as defensive armaments - in the case of the Sangheili and Jiralhanae, these factions lack sufficient scientific knowledge to maintain, repair or replace their current technology, nevermind improve upon it; and even the Prophet-led New Covenant has been reluctant to replace a technology that has served it well for millennia. So far, humanity, and in particular the UNSC, is the only faction to use SLB technology in any significant capacity. Attempts were made to miniaturize the technology for inforporation into MJOLNIR Powered Assault Armour, but the inherent design flaws of solid light barrier generation would see them superseded by electromagnetic shields.


The unusual properties of light have long been theorised, with photons exhibiting properties of both waves and particles, a concept known as wave-particle duality, which some interpretations of quantum mechanics explain is a property inherent in all matter in the universe. The full range of applications such a technology could be used for are little understood - the obvious applications are as solid planes, where photons are induced to behave as a solid for the purposes of interacting with normally tangible objects. The exact process has been classified DECEMBER BLACK by the UNSC Office of Naval Intelligence, deemed sensitive to exploitation by external and/or hostile forces. The photons themselves are formed into polygonal panes, arranged in a geodesic form to further improve the integrity of the shield, interlocking to form a solid and enclosing dome. Problems inherent in the design lead to the UNSC replacing it with electromagnetic versions for personnel - the interlocking geodesic design meant that using it as a personal energy shield hindered mobility, with most armour types unable to rapidly disassemble or resize plates that needed to be removed to allow shape change to allow movement, and lead to energy conservation problems. It would eventually be adopted as stationary defensive equipment, and on starships, but so far only Forerunner units have been observed utilizing such devices in any significant strength.

Solid light barriers possess advantages that electromagnetic shields do not - they are far more durable than electromagnetic shields, and being stationary possess long-term generators that prolong duration of shield integrity; they are far less vulnerable to electromagnetic fields, the dominant weaponry of the Covenant and former Covenant races; and have superior deflection properties for solid projectiles. They are also capable of encompassing a much larger area around the user device or ship than electromagnetic shields, and the geodesic nature allows them to form elliptical or spherical protective fields, removing the potential for weak points in the shield. It is also less observable to enemy sensors, and not as susceptible to RADAR sensors - the wavemotion properties allow low-velocity objects, such as personnel or vehicles, to pass through relatively unhindered, but reflect or deflect high-velocity objects, such as accelerated particles, plasma shots, and kinetic projectiles, and to refract/diffract laser weapons, all useful properties in engaging the various races that use Covenant technology after its almost total collapse in 2552.


  • "I'm glad they took the V-II/A out of service - moving in it was like wading through mud if you had the shields on, and deactivating them for mobility left you open. I wish they kept the Drop Shield function, though."
  • "My platoon was pinned down by a Spirit lobbing plasma at us - we dropped a bubble shield, hooked it up to the field generator, and waited. They ran out of plasma before we ran out of shield. I know you're not supposed to run it for long, but it saved our lives on Earth!"
  • "Theoretically, you could use such a system for holographic purposes - projecting solid interfaces for personnel interaction. But why would you when you could just build an actual touchpad? I know the Forerunners worked wonders, but sometimes the sheer wastefulness and extravagance makes me wonder what they were thinking."
  • "Photons do not work that way! Good night!"