Energy shielding

Energy shielding is any protective technology that utilizes energy field-based means (such as electromagnetism or gravitics) to deflect incoming damage. Energy shielding can be either passive (always on) or active (activated only upon imminent impact), and may be designed to deflect either projectile- or energy-based strikes, or both.

Proto-shields
Proto-shields are a category of electromagnetic impeller systems used as an advanced type of non-explosive reactive armor. Developed during the mid-Covenant War based on old, long-mothballed designs, they use a targeted strong electrogmagnetic field to reduce the energy of incoming directed energy weapon attacks; against projectile-based attacks, they are useless. Since the mid-war, proto-shield development was a gradient with the later years of the war already seeing fairly successful solutions though the technology would only mature and gain widespread adoption in the post-war period.

When used in vehicle armor, they are usually known as shock plates, or jolt plates. By the 2550s, many UNSC vehicles incorporated such armor.

Scalable to starship scale, wherein they are known as dispersal field generators. The development of increasingly efficient fusion drives capable of higher accelerations also saw the introduction of a form of proto-shielding funnels meant to protect ships from microcollisions when traveling at high velocities, though these would be far too weak to do anything against Covenant plasma.

Strike shielding
Battery-powered shields, fall after a few strikes and need a battery recharge or replacement to replenish. Became increasingly widespread on various armor systems over the 2560s.