Caveat: I am not a physicist, and my understanding of physics is limited to a New Zealand Sixth Form (equivalent to the twelfth grade) level, and what Wikipedia has taught me. And I was not very attentive during my Physics classes. If I have made a mistake or false statement, please point it out.

Sentinel Shielding

Small panes of either an electromagnetic field, magnetically contained plasma, or solid light, arranged into a geodesic shape around a Forerunner Sentinel.

When I look at the technology that Halo introduces us to, and I compare it to real life, I discover that while some artistic licenses may have been taken, the bulk of it remains true to real-life theoretical applications. The Spartan Laser, for example, is not beyond us - the US Army is testing the ZEUS-HLONS, coincidentally made by SPARTA Inc., a laser weapon mounted on top of a Humvee, designed to detonate roadside bombs, and while it has limitations that make implementation of it less than practical, it is a good sign that we are moving into a generation of technology once deemed too far fetched to be even considered outside of the borders of science fiction. [1] Yes, ladies and gentlemen, the next world war may be fought with lasers.

We may also be able to develop another of the staples of science fiction - the force field. The name is applied to basically anything that can stop physical and sometimes (but not always) energy attacks. But the actual implementation of such a system is often poorly defined, often relying on some made-up scientific principles. The early mentions date back to the 1920’s, in the works of E. E. Smith, and in 1912 when the characters of William Hope Hodgson's The Night Land are protected by something similar. But it is Star Trek and Star Wars that have made it famous. There seems to be no explanation for the exact physics of Star Wars shields, but Star Trek at least manages to scrape together something about concentrated gravitons. Elsewhere is hazier – Neon Genesis: Evangelion’s AT Fields are more spiritual than feasible, and the shields used by the Protoss in StarCraft are psionic generations. In almost every mention, shields are treated more as a MacGuffin – an object that serves only to move the story along.

To be honest, they really don’t need to bother with any of these explanations. Because humanity, right now, has discovered a small number of ways to create barriers that fit these criteria. And any of these could potentially be the source of the energy shields used by the Covenant, the Forerunners, and the UNSC.


The Chief gets his shields checked out by <random glowing testing device>. EM, plasma, or light?

There are theoretical proposals to generate a form of fake gravity in space – create an electromagnetic field through the surface of the ship which draws the objects within, including people, downward. Naturally the health effects of such a system are unknown, but shudder to imagine people suddenly finding iron pouring out of their feet. But why not do exactly the opposite – create an EM field along the outside of the hull? Theoretically, all matter has a charge (I think). Create a repellent field, and the matter will be repelled, like two positive magnet ends. In space, such a system would be extremely useful for deflecting micro-debris which, in the frictionless environment of space, would still carry significant momentum and therefore kinetic energy. Star Trek: Enterprise uses a similar system, before the creation of deflector shields, to repel unwanted shrapnel, and highlights the imperfections of such a system - in that for combat, given enough momentum any object will still penetrate it.

Given the Forerunner’s mastery of magnetic manipulation, and in turn the Covenant’s, it might be easy to conclude that this might be the method used. But the Forerunners and Covenant also mastered another technology – plasma. Partially ionised gases, and one of the more recently recognised states of matter, after solid, liquid and gas. The University of Washington and the Rutherford Appleton Laboratory are currently working on separate projects to launch a satellite that has a plasma “bubble” surrounding each, vaporising the multitude of debris left over from hundreds of space shuttle/satellite/probe launches, protecting the satellite from damage.[2][3] Given the mastery of these two principles, and the Covenant’s known use, if not preference, for plasma weaponry, I find this to be the most likely candidate for Covenant shields, especially on their ships. Rather than using magnetic fields to “deflect” debris, the magnetic field contains the plasma, which actively vaporises it. Halo: The Flood mentions that Covenant active camouflage gives off enormous amounts of heat, and that thermal vision can offset it. There is also the concept of Plasma stealth, which further reinforces this.[4] Things might get a bit hot, but Halo: First Strike confirms that Elites can turn their shields off when not expecting battle. Perhaps that’s why – to prevent overheating?

Shield wave 1

The Shields of a Spartan and Elite recharging. Compare the flickers with those of a light bridge when a character steps upon it, next time you play The Covenant.

The last concept is one that I find difficulty visualising the Covenant actively (or, given their pathetic understanding of the technology they use, knowingly) using, but would fully accept Forerunner use, and that is actual solid light. Photons made to behave as matter, rather than as energy.[5] Theoretically, it could lead to advancements in computer design. But Halo: The Flood describes perhaps the best description of a Forerunner application of solid light:

““I’m showing a lot of photonic activity,” Cortana said. “The excited photons have displaced the air around the light path.”
“Which means?”
“Which means,” she continued, “that the light has become coherent. Solid.””
— Exchange between the Master Chief and Cortana

For a long time, I’ve noticed a distinct similarity between the light bridges of the Forerunners, and the personal energy shields used by the Covenant and UNSC MJOLNIR armour. Light bridges are visible, while shields are not, but bridges are meant to be walked upon. Nobody likes walking in thin air. Shields are a defensive feature, and as such would need to be invisible not to impair the user’s vision or give his location away to the enemy.

Such a leap would be centuries ahead of the Covenant, never mind the UNSC, and its development would be long and difficult. The fact that the UNSC have been studying the Covenant’s technology for twenty seven years and are only just now beginning to incorporate shields into their forces leads me to believe that the UNSC at least have followed this path of development. The fact that it fades from vision when not actively in use also seems to imply control over photons, at least over the visual spectrum.

Regardless of what method is used, the power requirements would be enormous. I don't imagine this being a problem for the Forerunners, and would be manageable for the Covenant, but the fact that MJOLNIR suits need small fusion reactors to generate their shields speaks volumes about how far UNSC understanding of shield technology has progressed, and its implementation. "Bubble Shields" are already being distributed among the UNSC Marine Corps for limited defence, and in a few months, the UNSC may finally be able to field ships that are able to use shielding for the first time. But until they build up their infrastructure enough that they can do anything, I think MJOLNIR is as far as we can go with human shield technology in the near future of the Halo universe.

I’m not exactly sure how much thought Bungie put into the shield technology their characters, but we know from the detailed explanations of Eric Nylund, Robert McLees and Joseph Staten that they at least deliberated over the slipstream navigation technology they use. Why not shields? It might be worth sending off an Email to Frank O’Conner, current Field Master of Microsoft’s Halo-lore Legion, inquiring as to his take on Halo shields. I would be very interested in his response. For the moment, I’m going to leave this to a blog, rather than incorporate any of this into the article – I’m not going to make assertions that may turn out to be completely off-base. What opinions do you hold? Are there any with alternate theories? Improvements or corrections to be made?

For those of you unfamiliar with the technical jargon, I’ve included links to further information in the references section. Read about the HLONS, especially – I find it fascinating that a modern military force is using lasers in the field, while the UNSC is still trying to work out the kinks.


  4. Plasma Stealth
  5. Solid Light
  6. ’’Halo: The Flood’’, pg. 84-85