Star Trek Shields

Perhaps one of the most referenced fan sources in the Vs debates is Mike Wong's Star Trek shielding page. In this page he references many episodes, giving a brief description of how each leads to his conclusions. Here, I shall attempt to explain the many errors he has made in this page. All his original wording is quoted in yellow. To see the original site please click here.

Energy Handling Limits

First, by way of explanation: when entering the orbit of a star, the stellar radiation will strike the ship based on its distance from the star, its luminosity, and the ship's projected surface area, in the direction facing the star. Imagine taking a silhouette of the ship; the area of this silhouette is what the radiation from the star "sees". Now, a GCS is roughly 610m long, and 130m high when viewed from the side. If we assume that it is a rectangle, then its projected surface area is 78,000 m² (note that this is a very generous estimate- the ship is obviously not a solid rectangle when viewed from the side). In order to determine its rate of stellar bombardment, we take the star's luminosity, and divide it by 4(pi)(r²), where r is the radius of the star plus the ship's distance from the star's surface.

This is his first serious error on this page. Unfortunately, he applies his conclusions here to the rest of his arguments. Mike generously assume the area affected will be a box of roughly the same dimensions of the Enterprise. Obviously, this is very generous - if we are simply considering the ship itself. As the images below show, the box does have a far greater surface area than the ship. However, Mike appeared to have forgotten that he is discussing the effects of radiation on the shields of the Enterprise. Unlike Star Wars shields these are not hull-conforming. Infact, they extend quite a distance from the ship. In the video capture image below the shields have a height of almost 600m, and extend beyond the front of the ship by over 200m. If we assume the shields extend from the rear of the ship by a similar amount, then the length of the shields will be over 1000m. This gives an approximate shield area of (pi)(length/2)(height/2) = 470,000m^2, or nearly six times what Mike has used above. If the ship is projecting its dorsal or ventral silhouette it will be an area of over 600,000m^2. The minimum the shield silhouette could be (from a frontal view) is 375,000m^2. As you can see, in his haste to be generous Mike has failed to consider the very technology he is discussing. This error is repeated throughout his shield estimations.

[Editor's note: He had a table here with four images in it. Three of four links were broken when I tried to download the page so I didn't bother copying them, but let's just assume that they showed what he says they showed, and that the broken links are due to sloppy site maintenance]

In Descent Part 2 the Enterprise-D moved deep into the corona of a star using special metaphasic shields, and its chief engineer estimated that its shields would fail within 5 minutes under this bombardment. Based on the presence of a habitable planet in that star system as well as the colour spectrum of the star, we can conclude that its star was very similar to Earth's star in terms of general luminosity. An upper limit on its power absorption would therefore have been 64 MW/m², since the power intensity at the surface of Earth's star is only 62 MW/m². Therefore, the ship (with ~78,000 m² projected area) absorbed roughly 5TW. The 5-minute survival limit indicates that their thermal energy absorption capability is roughly 1500 TJ, or roughly 350 kilotons.

Having decided the area of the E-d, Mike then goes on to interpret episodes where we are shown the limits of what the ship can handle. Once we apply the correct surface area, we find the energy the shields would have encountered over 5 minutes in Descent pt II was over 30TW, for a total energy over 9,000TJ from an already damaged ship using an experimental technology.

In "Relics", the Enterprise-D was pulled into a close orbit (150,000km) around a star enclosed in a Dyson sphere. This star was a G-class star which was most likely less than 45% of Sol's luminosity because the Dyson sphere was 2E11m in diameter (66% of Earth's orbital diameter) yet green vegetation and bodies of water could be clearly seen on its inner surface. If the star had been as luminous as Earth's sun, the bodies of water would have quickly boiled away and the vegetation would have been destroyed. The star is said to be releasing a lot of prominences, but we never see the ship actually get engulfed in one of these prominences so they aren't really relevant. At a 150,000km distance from that star's surface, the power intensity would be roughly 25 MW/m² so the ship would have been absorbing roughly 2 TW of power. Its shields were down to 23% and their shields were being depleted by this bombardment, so an upper limit for shield strength based on this incident would be less than 9 TW

Again, Mike applies his earlier error and comes to the wrong conclusion. In this case, the shield was likely to be experiencing a power intensity of over 15TW, at a shield efficiency of 23%, roughly corresponding to 60TW or higher for full shields.

It must be noted that the ship was on auxiliary power at the time, but it takes a long time to recharge shields even with full power functional so they seem to be more like a "battery" that is charged up before battle and then drained. For that reason, the 23% may refer to the remaining energy dissipation capability rather than its steady-state power dissipation capability, and the ability of the engines to rebuild the shields isn't really relevant (battles certainly don't last for three hours; they normally don't have time to even attempt to recharge shields in the middle of battle). Since they claimed to be able to withstand this bombardment for 3 hours, we can conclude that their total shield dissipation limit is less than 100,000 TJ.

Mike is correct that they could withstand their bombardment for three hours before shields were expected to fail. What he fails to point out is that the main threat is not the incident energy from the star itself, but the numerous stellar flares that they were enduring at the same time. It was these that prompted Riker to check whether the shields were up, and it was the fact that the flares would continue to grow that caused Data to say the shields would fail within three hours. Once we apply the correction to his shield area, we discover the shields were expected to withstand over 160,000TJ BEFORE taking into account the effects of the growing solar flares. These figures are not upper limits as Mike claims - they are LOWER LIMITS, as these are figures we know for a fact the ship can withstand, despite being low on power and beginning with already weakened shields.

(update: 20/6/01 Wayne Poe has had a go at refuting my claims. I'd like to take this opportunity to thank Wayne for providing four further examples where the shields of the Enterprise are, very clearly, BEYOND the "very generous" box Mr Wong attributes to them. If you want to be generous, you use numbers that are likely to be higher than the ones really applicable to that case. Each one of MW's examples are likely UNDERestimates. As for the DS9 examples, anyone who has seen Call To Arms should know a new shield configuration was developed to counter the dominion threat - a shield configuration that was far more hull-hugging than those of TNG and early DS9 era (infact, Voyager retains the bubble shields, having left the alpha quadrant prior to their adoption). Even so, not one of the DS9 images shows a ship being hit by weaponry, so we cannot say whether the shields support MW's claims of a generous box or not. The third DS9 image, which shows a ship busy destroying itself after being attacked, is totally redundant, as the shields must be down for the ship to be receiving the damage it is. Wayne has failed to prove MW was being "very generous" in assuming the shields had the exact dimensions of the E-d, and has not even attempted to refute the other half of the critique dealing with the charged particle weakness. If Mike Wong's assumption is generous it should be easy to find an example prior to Call To Arms to support his case )

Effects of Plasma

There remains a possibility that the high temperature gases and charged particles are extremely deleterious to shields. There is a long history of charged particles being extremely dangerous to shields.

In "Survivors", an antiproton beam (charged particles) easily disabled the Enterprise-D's shields with a mere 200 GJ of energy (a 400GW 0.5-second burst).

In Survivors an antiproton beam fired by a superbeing easily disabled the Enterprises' shields. The energy of this beam was far lower than other shield limits would indicate (for example, a photon torpedo will generate many charged particle with an energy in the low megatonne range - yet shields can withstand these with little problem). Using this as an example of shield ability is similar to using the Traveler episodes as examples of normal warp speeds, or using Q Who(where the E-d was thrown across the galaxy without the people on board falling over) as an example of what the inertial dampers can handle.

In ST2, the ambient charged particles in the Mutara nebula totally disabled the shields on the Reliant and Enterprise.

In ST2 Savick explained the electrostatic discharges in the Mutara nebula would cause problems for their shields and sensors, and very soon after we saw they did. In Best of Both Worlds, the Enterprise hid in the Paulson Nebula, in Imaginary Friends the Enterprise enters a nebula and Geordie specifically states "nothing the shields can't handle". In One the Mutara class nebula had no effect on their shields. These are just three of many examples where ships have entered nebulae and NOT been affected by their charged gasses.

In ST:G, a "low-level ionic pulse" penetrated a BOP's shields and affected its warp coils.

In this example the ship in question was a very old damaged BoP. The fact that a low-level pulse was used specifically to force the ship to cloak might indicate that Star Trek shields can operate on a threshold basis - the ionic pulse in question was certainly not enough to threaten the BoP as it caused no damage beyond forcing them to cloak. If anything, this is a better example of a weakness of old Birds of Prey than shields.

In "The Inner Light" a low-powered nucleonic beam (remember that protons are charged) penetrated the Enterprise's shields, even though it originated from a vessel built by a society that was so primitive that they had not yet developed space travel.

Here, again, Mike is misrepresenting the episode. Initially the probe is emitting a nucleonic beam which probes the shields, then it emits an "unusual particle beam" which penetrates the shields. You will also notice Mike assumes that, because the society has not demonstrated space travel beyond the probe the Enterprise encountered, all their technology must be primitive. This assumes that the influences that drive technological development are the same for all races, when they obviously are not. This race chose to concentrate on prolonging their living memory rather than transporting the people off the planet. Voyager's Fair Haven also showed shields were susceptible to the effects of nucleonic particles - but those were high-energy chargeless neutrons. In Voyager's Unforgettable Harry Kim was able to counteract an very focused proton-based particle beam that was designed to "penetrate any shield, even if the modulations are changed"

In "Starship Down", the Defiant loses all shield function when it encounters the charged particles in a gas giant's atmosphere

In Starship Down the Defiant entered a gas giant's atmosphere, but their shields did not fail because of the charged particles in the atmosphere. Infact, the charged particles were never stated to be a problem. The major worry was the 10,000km/h plus wind speeds. When the shields of the Defiant did eventually fail it was due to attacks from the two Jem Hadar ships that followed them in. These images clearly demonstrate the shields were still up some time after the ship had entered the atmosphere.

[Editor's note: He had a table here with three images in it. All three links were broken when I tried to download the page so I didn't bother copying them, but let's just assume that they showed what he says they showed, and that the broken links are due to sloppy site maintenance]

In "Interface", the Enterprise-D is unable to enter the atmosphere of a gas giant due to the atmospheric effects.

Mike is spot on with this one - in Interface the E-d was unable to enter the atmosphere of an unusual gas giant due to the very high turbulence within. However, the problems had absolutely nothing to do with the shields. Infact, a shuttle was sent into the atmosphere BECAUSE its shields would protect it. This quote has no place in a page about shields, and certainly not in a list of examples of shields being susceptible to charged particles.

In "Arsenal of Freedom" the Enterprise-D is almost destroyed by the heat of atmospheric re-entry.

In "Arsenal of Freedom" the Enterprise entered the atmosphere of the planet at high speed. It glowed brightly, but its surface temperature only approached 4000K. In Descent the hull temperature reached 12000K before nearing critical, and 7000K was declared a safe temperature. Mike's assumption that the E-d was almost destroyed is based entirely on the fact it glowed brightly. Does this mean the space shuttle is nearly destroyed every time it enters the earth's atmosphere? Certainly not - if it was they wouldn't use it. It is merely operating within it's designed safe parameters, where the ablative covering ont eh surface is doing its job. Again, this quote has zero to do with the effect of charged plasma on shields, as the shields protected the ship against the ionized atmospheric gas. This would better serve as indication of some form of minimal ablative covering (not as much as the ablative armour later included on ships such as the Defiant)

As noted previously, in "Descent Part 2" the Enterprise-D's resistance to stellar radiation was less than 1/30 of its resistance in "Relics", even though it was running an experimental metaphasic shield program at the time. The only consistent rationalization is that they have extreme difficulty maintaining shields when surrounded by charged particles, and that the charged-particle density at their altitude was sufficient to create this sort of disruption

Another possible rationalization is that the ship was damaged, or that the experimental and unreliable metaphasic shield program draws so much energy that is can only be used for a short period of time (this second rationalization is actually supported by one of the few admissable Star Trek novels - Mosaic)

In "Descent Part 2", the Enterprise induced a solar prominence to destroy a Borg vessel. The largest solar prominences are known as "coronal mass ejections", or CME's, and in such a prominence, the mass and velocity of ejecta are typically around 1E12 kg and 400 km/s. Anomalously large CME's have involved masses and speeds of as much as 1E13 kg and 2000 km/s in the past. However, the prominence in "Descent Part 2" was nowhere near this size

It may have been nowhere near this size - it was also nowhere near this speed. The Borg ship took up position outside the corona of the star, and the matter from the induced flare reached the ship in a few seconds. This is several orders of magnitude faster than the fastest CMEs ever seen. It was also not a natural flare, but one induced by the Enterprise. As such, we cannot determine it's density, magnetic intensity, or even the thermal energy of the material involved. Finally, this example was for an unshielded Borg BOMB (the ship was exactly the same as the schematics for the Multi Kinetic Neutronic Mine of Scorpion). hardly a shining example of the ability of Star Trek shields to withstand a certain level of energy or type of material.

Out of the NINE examples Mike has offered of shields being susceptible to charged particles only TWO are directly applicable to modern Trek shields.

Due to the serious errors presented above the conclusions of the page, based largely on the erroneous assumptions, are thrown into doubt.

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