Shields

Type 1 Shield:             Electro-Magnetic Toroid (EMT)

Theory/History:          

Electro-Magnetic Belts are naturally occurring torus’ of energetic charged particles (plasma) found around the majority of life giving planets and are held in place by the planet’s magnetic field.  E-M Belts are typically near to their associated planets polar aurora where particles strike the upper atmosphere and fluoresce.  The study of these E-M belts led to the successful creation of the first mirror fields, which were used to control the plasma flow required for controlled nuclear fusion.  This included the added benefit of blocking the hard radiation generated by the fusion reaction.

As races expanded into deep space this benefit and the mirror field generators were expanded to create the first Electo-Magnetic Toroid intended to protect the crew against the effects of interstellar radiation.  It was later discovered that a field of sufficient power proved effective against energetic weapons fire, absorbing and or deflecting most of the energy directed at it (Fig 1).  Since then the EMT has continued to evolve and be refined to the point where they are seen as the standard in combat shielding.

 Function:        

EMTs function by generating a coherent energy field consisting of negatively or positively charged particles trapped within a magnetic field around the craft in the shape of a torus.  The suspended particles are kept in a constant EM controlled loop around the craft at near relativistic speeds.  The thickness of the field, density and speed of the particles varies by shield class.  The immediate benefit of this shield is apparent as it protects the crew from harmful stellar radiation, without the need for heavy, thick, plate radiation shields.  Combat grade shields are further capable of protection against energy based weapons, deflecting or absorbing the incoming energy before it can interact with the ship.  However any kinetic energy inherent in the incident fire will transfer through the shield into the projector, mandating strong shock mounts on the shield generators (Fig2).           EMTs lose effectiveness as more outside energy impinges upon them.  Energy bolts striking the charged particles of the toroid alter and interrupt their flow.  Additional energy is then required to restore the flow to its original speed and shape, draining shield energy.  The charged particles can also be knocked out of the toroid flow, weakening the field until the particle volume can be restored. 

EMTs are not impervious to incoming fire and even in a fully powered state impinging energy bolts can overwhelm and breach the field (Fig 3).  These are the methods by which EMTs are overwhelmed and breached by hostile fire.  It should be noted that any energy beam or bolt that breaches the field without collapsing it will be displaced dependent on the strength of the incoming energy packet and of the field.  The incident energy will also have its course altered by the flow of the field. 
EMTs are considered of limited usefulness against Kinetic Kill weapons.  However the Electro-magnetic nature of the field can deflect ferrous or magnetically charged objects, just not as effectively as energetic bolts.  EMTs can even effect unshielded missile guidance systems and explosive warheads, causing loss of guidance control or premature detonation.

Application:   

In practice EMTs are set into a constant longitudinal or lateral spin around the projecting craft when used in space.  This is in order to cover the gaps inherent in the toroid shape (Fig 4).  The rotational speed of the toroid is unique and tunable to every projector; tuned to all onboard, sensors, communications, and weapons systems in order to prevent harmful interaction with the toroid.  Wherever possible the EM Field projectors that maintain the toroid are mounted external to the ship, but in cases where that is not possible (such as on strike craft), all equipment along the plane of rotation with the internal projector is heavily EM shielded. 


Figure 5. (Typical Fighter EMT Interference Diagram)

Combat ships normally employ multiple projectors in order to provide several layers of protection.  These ordinarily take the form of inner and outer toroid shells.  In the case of fighter scale craft however, the toroids are kept at approximately equal.  The individual projectors (usually two) are then displaced from each other creating the dual layer effect.  The unfortunate side effect of this is the formation of interference zones where the volumes of space where the toroids interact, disrupt the fields and create possible weak points (Figure 5).  This is due to the fact that the plasmas of each toroid are, by design, kept at polar opposites in order to maximize their effectiveness against incoming fire. 

Notes: 

  • Minimal lensing occurs to visible light when it passes through the field.  This can be easily corrected by adaptive optics onboard ship.  However it has caused concern amongst many individuals when they see inbound lasers impact their hull virtually unmolested not realizing that the field has absorbed/deflected the weaponized plasma charge.
  • Any kinetic energy inherent in the object impinging on the shield will transfer into the field projector, mandating the use of heavy shock mounts.
  • EMT fields will have no effect on objects of a purely kinetic nature that are not of a ferrous make up or otherwise charged.  These objects will breach the field with little to no additional effort.
  • EMT fields will effect and possibly deflect ferrous materials or objects with an EM charge.
  • Personnel should remain clear of active EMT Fields wherever possible.  Injury can occur should contact transpire, primarily in the form of plasma or radiation burns.
  • STL sensors, communications and energetic weapons used by any craft equipped with an EMT must be configured with control circuitry that will allow them to operate in tandem with the EMT.  In the case of weapons, timing circuitry is required in order to make sure that the weapons will fire through temporary gaps in the EMT field.
  • If an E-M Field projector is carried internally, all equipment along the projector’s rotational plane must be EM shielded in order to avoid EMI hazards.

Type 2 Shields:           Gravitational Deflector Field (GDF)

 Theory/History:

Shortly after the first Anti-Gravity Field (AGF) generator went into use in the transportation of heavy cargo scientists realized that the field it generated not only repelled it from a planet’s gravity, but that it repelled lighter objects that came close to it.  This was originally referred to as the anti-gravity wake effect because as an AGF equipped vehicle passed over loose soil or water it left a wake in its path much like boat passing through water.  It wasn’t much longer until the military realized that these same AGFs could deflect low velocity (relative) kinetic projectiles. 

Experiments ensued using these AGFs.  Engineers discovered that even low powered AGFs, when focused could deflect and or absorb the impact from kinetic projectiles.  This led to the creation of combat shield tuned AGFs.
However, any all-encompassing AGF capable of defending against larger scale kinetic projectiles was prohibitively heavy and power consuming.  Several different alternatives were discussed for this, including frequency shielding (which turned the fields on and off at regular intervals), plate projection (which used multiple lower powered projectors, each focused on different regions), and finally screens (which only activated when hostile fire was imminent).

The power problems associated with AGF based shields were never overcome, but as deep space exploration progressed AGF shields found a new life as Navigational Deflector Fields (NDFs).  These NDFs were mid-strength AGFs mounted to the front of long range exploration craft and were focused in such a way to push stellar debris out of the way of the ship.  This was found to be much more cost effective then traditional heavy armor plating, which had to be repaired and replaced often.
As seemed inevitable one of these long range explorers came under attack by hostile forces using kinetic weapons against which the ships EMTs were of little to no effect.  The captain of the ship ordered full power to his NDF and turned the craft towards the enemy, creating an effective barrier against the incoming weapons.  Engineers aboard the ship began to tune the focus of the NDF and were soon able to steer it in front of incoming projectiles, thus creating the first true Gravitational Deflector Field (GDF).

Function:

GDFs come in two types.  The basic Navigational Deflector Field (NDF), which is little changed from its original form, except for refinements in design which allow for a stronger field projection for minimal power consumption and, the combat level GDF.  As opposed to the EMT the GDF does not create an Omni directional barrier.  Instead GDFs focus on specific volumes of space around the projecting craft.  The most basic GDFs use the same technology inherent in AGF generators and project a screen of focused anti-gravitation waves away from the ship.  This creates a repelling effect against any and all incoming matter, slowing or deflecting the matter away from the projector.  More powerful GDFs use gravitons to create a similar effect but are reserved as deflectors as these GDF screens are manipulated to “bend” matter around the projector instead of deflect it away.

When used inside of a gravitational field an AGF floats because it creates a field of anti-gravitation waves that cancels out the gravitational waves in the gravity field, repelling the object with the lowest gravitational potential.  The same principal applies to the GDF.  The focused anti-gravitational waves, act against the incoming kinetic mass and because its gravitational potential is far lower then that of the projecting craft, repels it.  This repelling force works to slow the incoming mass and in the case of a mass impinging on the field directly can stop, and in some case reverse the direction of the mass if its kinetic energy is lower then the gravitational potential of the projected field (Fig 6). 

If the kinetic energy of the incoming mass is greater then the gravitational potential of the GDF however it will breach the field, though at a lower velocity due to its interaction with the field (Fig 7).  This can however result in the collapse of the field because the field will attempt to stop the incoming mass, drawing more and more power until it reaches a failure point.  For masses that impinge on the field at any angle away from perpendicular their velocity parallel to the plane of the field will not be affected by its interaction with the outwardly focused field and if the field is able to counter its incoming velocity will deflect it away (Fig 8).

 Application:

Fig 9. GDF types

As has been addressed it takes a great deal of energy to stop an incoming mass with a GDF.  As such, it is better to try and deflect it.  In practice this is how the majority of GDFs function.  Computer controls will manipulate the GDF such that the incident mass comes in at as great an oblique angle as possible.  In the case of NDFs the field is projected into a long ellipse in front of the craft, such that only mass striking the very tip of the field coming in is incident to it.  Combat field generators are computer controlled, the computer analyzing the vector of incoming projectiles and angling the field to allow for the strike at as an oblique an angle as possible.

GDFs have very significant power demands, especially when compared to EMTs.  An EMT typically has three operating levels, initial power on (which is the greatest power draw), sustainment (which requires relatively little power to keep the EMT in focus), and recharge (which can draw as much power as initial power on depending on the level of field disruption).  By contrast a GDF requires near constant power in order to generate its anti-gravitation field, project the field, focus it and continually replenish it.  This creates significant mass and energy penalties in the design of a starship, where mass and energy need to be kept at a minimum.

It is because of this that usually only combat starships are equipped with anything more then a NDF.  Light combat ships are equipped with a minimum of GDF projectors; these projectors are of a steerable type and are only activated during combat when hostile fire is expected.  At all other times, they are kept in a standby mode.  In order to save on mass, most fighter GDFs use the anti-gravitation wave generators built into their de-grav generators.  These de-grav generators are typically also combat certified making them useable as GDF projectors.  However these projectors are invariably mounted on the ventral surface of a fighter making them of little use for dorsal attacks.  To account for this additional projectors are mounted to the strike craft’s dorsal surface, but are fed by the de-grav generators anti-gravitation wave generators.  By contrast, capital scale starships are equipped with numerous GDF projectors with integral anti-gravitation wave and or graviton generators.  These projectors create overlapping fields of protection all around the capital ship, but require even more power to operate as a consequence (Fig 9).  Interference zones can also be created where to projected fields overlap, the vectors of the anti-gravitation waves often interfering and disrupting the gravitational potential of the region.

 Notes: 

  • Significant lensing effects can be observed when a combat grade GDF is operational due to gravitational distortion and are more noticeable in graviton based GDFs.  These effects are only visible when the GDF is at power however and adaptive optics are capable of overcoming all but the worst effects.
  • Any kinetic energy inherent in the object impinging on the field will be transferred into the field projector, mandating the use of heavy shock mounts.
  • Energetic weapons have been known to be effected by GDFs, but use of a GDF against energy based weapons is not advised due to the significant power demands required to counter energetic weapons.
  • Automatic cut offs should be installed in all GDF control software in order to prevent a GDF from burning itself out attempting to deflect a mass with too much kinetic energy.  This will however result in the mass breaching the field to be stopped by the craft’s hull armor, but will prevent the complete loss of the GDF projector.
  • Personnel and loose equipment should be kept clear of active GDF projectors as pulsing is possible which will repel any mass in front of the projected field.
  • STL sensors, communications and energetic weapons used by any craft equipped with an GDF must be configured with control circuitry that will allow them to operate in tandem with the GDF.  In the case of weapons, timing circuitry is required in order to make sure that the weapons will not fire into the GDF field.

NDFs should not be used in place of combat GDFs due to the high risk of failure against high kinetic energy projectiles.

shield locations
Figure 10. (Shield Projector Locations (typ)) (Designs under revision)

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