Gateworld Virtual Fleet 4.0 - Discussion thread

[Cmdr. Setsuna F. Seyei]

why not create a nano machine counter agent for radioactive particles? and have some sort of neutron jammer in place to prevent catastrophic meltdown incase of a reactor breach on a ship or if a ship is about to crash it auto activates? and have the nano machines as part of the reactor casing to prevent radiation leak incase of breach of casing.

[thekillman]

why not create a nano machine counter agent for radioactive particles? and have some sort of neutron jammer in place to prevent catastrophic meltdown incase of a reactor breach on a ship or if a ship is about to crash it auto activates? and have the nano machines as part of the reactor casing to prevent radiation leak incase of breach of casing.

Well there are two main problems here:

*the reactor is mediated by some kind of neutron jammer in the first place. Carbon rods, water, etc. A nuclear reactor melts down either because this neutron absorbtion mechanism is broken (i believe that in Chernobyl, the carbon rods burned away due to testing with a way too high reactor temperature) or the cooling is broken (Fukushima had old diesel power engines to power the pump that cooled the reactor). So basically, a meltdown only happens because the safety fails. modern reactors have so many safeties that a breakdown can pretty much only happen through human error. (e.g. fukushima would've survived easily had the backups not been old diesels but more modern solutions).

*Radiation protection, especially against the bad kind, needs a ton of material between it that absorbs that given particle. Neutrons are best absorbed by neutron rich material (e.g. parrafin or water). Photons best by lead or other dense materials. So a nano agent isn't going to do much if there's a rupture in the chamber. Self-healing materials work, but we're talking small cracks here (mm or smaller).

Not that nanoparticles serve no purpose at all, it's just that they're for cleanup (many plants are known to be able to differentiate between the isotopes of some elements. So a nanoparticle would bond only to the radioactive isotopes and have some mechanism to clump together and filter the air and surroundings)

[Gormagon]

How good are our current infrared sensors and ground penetrating radar for detecting say...body heat, diesel generators, or nuclear batteries under ground in mines at varying depths, say in the dozens to hundreds of meters of varying types of rock?

[thekillman]

How good are our current infrared sensors and ground penetrating radar for detecting say...body heat, diesel generators, or nuclear batteries under ground in mines at varying depths, say in the dozens to hundreds of meters of varying types of rock?

Zero.

Well i don't know about ground penetrating radar. However, infrared has the very useful property of being absorbed by electron bonds of various kinds (so extremely useful in infrared spectroscopy). It's penetration depth is in the order of millimeters, though it depends on the exact kind of material you're penetrating. Still, the ground isn't something known to be transparent to IR. So trying to find body heat under anything more than a few clothes is absolutely pointless. Ever seen one of those police chase TV series, the chopper turns to infrared cameras to track the guy? that's roughly what any IR will look like. Maybe of higher or lower quality, but body heat (37 degrees C) is a relatively common temperature. So while it's a christmas tree when a guy walks in a field, when other heat sources are nearby it gets a lot harder.

Heat seeking missiles work because the temperature of a jet engine lies in the hundreds of degrees. Flares burn at a roughly similar temperature, so the heat seeker can't distinguish as well between a flare and a jet engine.


Wikipedia suggests up to 5 kilometer penetration depth, but reading a few more lines, i get to the line i expected, namely that it heavily depends upon soil composition.


It does depend on what you want to detect.

[Gormagon]

I am allowing a technology similar to Quantum stealth (As in several centuries ahead) to be used for planetary scenarios and combat, is there a theoretical possibility of stealth suits not setting off motion sensors?

What about detecting radiation stored nuclear devices? I'd guess the same because they are going to be well shielded already then under tons of rock.

[thekillman]

is there a theoretical possibility of stealth suits not setting off motion sensors?

Well AFAIK motion sensors work by detecting a sudden shift in light. If your stealth works properly, motion would not be discernible.

What about detecting radiation stored nuclear devices? I'd guess the same because they are going to be well shielded already then under tons of rock.

I was thinking about this. Passively detecting it won't work probably, but maybe some form of active sensor might.

[Gormagon]

• Proton beam: Proton beams are used for combat in vacuum.........

Spoiler:

Individual protons are accelerated to ultra-relativistic velocities. As the beam exits the accelerator, it is neutralized by injecting an electron beam to cancel the charges. This prevents self repulsion from defocusing the beam and keeps the beam from veering in ambient magnetic fields.

The primary limit to the range of a proton beam is the thermal velocity of the protons. Neutralization of the beam unavoidably heats the beam due to the energy of recombination with the electrons. After exiting the accelerator, they begin to drift apart at roughly 15 km/s. The higher the proton energy, the farther the travel in the time it takes the beam to disperse.

Proton beam accelerators are typically circular tracks several dozen or hundred meters to several tens of kilometers in diameter depending on your technology level. Even the largest, and/or most advanced proton accelerators do not give their protons enough energy to rival x-ray lasers in range, and thus x-ray lasers dominate for deep space combat. Proton beams are typically employed in craft designed for combat in planetary orbit, and find use in blockades and operations to achieve orbital superiority prior to a ground assault.

Like electron beams, proton beams can be steered with magnets prior to neutralization. In addition, the beam can be emitted from several ports along the ring diameter, allowing rapid retargeting.

The relativistic protons in these beams can be extremely penetrating, typically punching through a meter or so of solid or liquid matter before disintegrating into a shower of radiation, which itself can penetrate many more meters of solid or liquid matter. These "cascade" radiation showers produce an extremely high radiation environment which will sterilize the area of all biological life and destroy unhardened electronics. The only defense against a proton beam is thick layers of inert shielding, or using only radiation hardened control systems. Proton rich shielding is most effective on a per-mass basis.

In an atmosphere, proton beams lose energy through ionization and direct collisions with the nuclei of air atoms, limiting their range to a few hundred meters in earth-like atmospheres. While this is comparable to the range of electron beams in air, an electron beam accelerator is much more compact.

...............Can a magnetic / plasma shield stop a neutral particle beam, like this balanced beam with electrons and protons? I know that the same means used to accelerate and direct the beam can be used to defend against it, (For instance, Gravitoelectromagnetism used to create the magical neutron beam then to make a 'shield' against it.)

We are using magnetic plasma shields, (Eventually incorporating gravitoelectromagnetism and/or the fifth force with exotic particles depending on technology level) but do you have any more thoughts on shield uses and functionality of the shields VS all weapon types both energy and kinetic/ballistic, like effectiveness, weaknesses, strengths ect.

Possibly obvious question, why is a mag/plas shield good vs lasers when lasers have no charge?
Can charge be alternated in both beams and weapons to try and counter the repel effect?
Might running a nuclear drive with shields up melt and or damage your ship by containing the plasma exhaust, requiring adjustment?
Do these shields weaken over time, or do they have a set effectiveness level as long as power flow is maintained?
Is the only really good way around them to focus fire on the shield emitters to try and knock them out via any energy that passes through the shield?
Do they mess up sensors?
What about small craft and ballistics/kinetics/DEWS passing in/out?
Any thoughts on how to regulate the *Gravmagnetism* E5 force to keep it non OP?

[thekillman]

Can a magnetic / plasma shield stop a neutral particle beam, like this balanced beam with electrons and protons?

I think you just run into the good old kinetics problem. I don't think the particle beam gives the plasma shield enough time to get any reaction going. However, 15km/s dispersion is still pretty fast, though i'm not sure what kind of system is behind it. Reading that description, it would probably require a massive, massive gun to get beyond laser range.

Possibly obvious question, why is a mag/plas shield good vs lasers when lasers have no charge?

Simply put, the shield acts as a mirror. E.g. our ionosphere acts as a mirror for radio signals. In stead of doing all sorts of complex things, radio range is massively boosted by bouncing it against the ionosphere. It's also where the typical "few moments of radio silence" thing in movies come from when ships re-enter.

Can charge be alternated in both beams and weapons to try and counter the repel effect?

Lasers versus plasma you mean? no. Only a higher frequency laser can penetrate the shield. Or maybe a sufficiently powerful reflected one. (since reflection is never perfect)

Might running a nuclear drive with shields up melt and or damage your ship by containing the plasma exhaust, requiring adjustment?

You can not shield your exhaust if that's what you're asking. It would either (locally) damage the shield, pollute it or maybe reflect onto your ship.

Do these shields weaken over time, or do they have a set effectiveness level as long as power flow is maintained?

It's still matter. So you could blast it off. I don't know about the actual density and stuff of the plasma around your ship, but there's a good reason to believe it may be easy to regenerate over time. However, quick successive blasts might locally damage the shield allowing shots through -before nearby plasma moves in and fills the gap-.

Is the only really good way around them to focus fire on the shield emitters to try and knock them out via any energy that passes through the shield?

The shields would require tremendous amounts of power. If you go for realism, it would cause a massive buildup of heat in the ship. Depending on how extreme the defense is, it may be a case of seeing who's ship is about to boil first, rather than who destroys who.

Do they mess up sensors?

If your sensors are EM and require a wavelength below your shield's wavelength, yes.

What about small craft and ballistics/kinetics/DEWS passing in/out?

Ballistics would almost certainly penetrate the shield like it's not there. If they go sufficiently fast, thermal effects, stress effects etc wouldn't matter. The obvious issue of bullet speed remains, but other than that it would be a great weapon.

DEW is a very generic term, can't do much with that.

Small craft may be equipped with a similar shield to protect from the larger shield. I'm not an electric engineer, but something tells me both craft won't quite like it.

Any thoughts on how to regulate the *Gravmagnetism* E5 force to keep it non OP?

You're only talking about the current holy grail of modern physics......

[Davidtourniquet]

Hi guys,
I thought I'd pop my head through the door and see what's been happening.
It's been a while.

[thekillman]

Hi guys,
I thought I'd pop my head through the door and see what's been happening.
It's been a while.

hey man good to see you. How's things going?

[Gormagon]

The grammar here is terrible. Can you decipher this to see if its any good?

"Nope, looks good, just tell him that only crap shields would actually allow plasmatized or vaporized projectiles through. If the shield is focused at all properly, it will react as an impermeable barrier to all solid matter. And at different wavelengths and higher power, even light. The only limiting factor is that for every 'push' of incoming weaponsfire, your shield gene's have to push back equally. That's how to overload a shield, push hard enough in one spot and overload all gene's in the area. The closer the gene, the harder you have to push (think of a lever with the fulcrum far away, versus very close at hand; which is easier to move?) So find the biggest spot where all local generators are equally far away, and blast away!
Still, he is right in that light is faster than any bullet. So most or all gene's will be tuned higher, to refract, reflect, or absorb light from laser weapons (also, laser - based range finders won't work on the best sheilds, the ones that absorb. No light returns to the sensor, it's all absorbed!
One thing to note is that the shield cannot operate when the primary engine is running, or at least cannot cover it during operation. Otherwise the burning gasses or ions or plasma or whatever would bounce off the shield and fry the ship! With the added bonus of not pushing you anywhere and burning out all shield genes in the area. Have fun choking on your own emmisions!
Maneuvering thrusters would work, as would having a sectioned shield, one you could selectively turn off and on specific areas, such as covering the engines, and weapon ports. I think I'd automate the weapon port covers to open just before and shut just after. No way around that. Have to take them down to fire. Best to be selective."

What the heck are these 'genes" referred to in this quote?

[thekillman]

The grammar here is terrible. Can you decipher this to see if its any good?

Genes means generators. There seems to be quite a big misunderstanding (or disagreement) over the type of shield used and what it does.

Spoiler:

link for video here:
Shields Up! The Physics of Star Wars


Their paper isn't as big as i'd hoped it would be, and is in fact quite basic science and math. Well except the plasma reflection part, didn't know that.

Paper:
http://physics.le.ac.uk/journals/ind...e/view/678/486

However, i think it's very interesting and i can apply some of my engineering knowledge to give some order-of-magnitude estimations.

First off, the paper contains a figure (figure 1) that plots light frequency against magnetic shield strength. reading this, we can get almost into X-ray territory with current engineering. There's a catch, and i'll show it.

http://www.sciencedaily.com/releases...0628112314.htm

The above link is referenced by the paper and shows where that 91.4 T magnetic field figure comes from. However, the coil is actually pretty big and the actual 90T field is only a small volume. The coil is 20x (literally!) bigger than the diameter of the plasma shield. That and the complexity of how to actually properly build a plasma shield contained from two sides, means you'll need a LOT of coil per surface area of plasma.

Lastly, the coil only generates this field for a few microseconds. Since the trouble seems to be the material involved (a similar problem to Railguns, really) because the Lorentz force tries to rip the coil apart, future technology may reduce the coil:shield ratio quite a bit, but it's doubtful that the amount of shield will ever be >>> the amount of coil.

(sidenote: it also requires a ton of power to make this shield, but i can't yet find how much.)

As to practical problems:

The shield reflects EM. Specifically, in what is perhaps the ultimate Scifi/science twist, it reflects EM that matches the frequency of the shield, and anything lower in frequency. So if you have a high-UV shield, you need something better than high-UV (e.g. X-ray) to see through it.

Now, if you're at a point where you can build this shield and power it, then you'd also be able to open up holes. Maybe not dynamically at first, but that's of little importance. Unless we're talking sub-100m ships or so, the surface area of turrets, sensors etc <<< surface area of the ship. That is, if the enemy were to look through his scope at your ship, he'd mostly see shield and a few dots where the turrets are exposed.

Then, utilizing sensors etc is a matter of putting it on a retractable boom, sticking it through the shield (and equipped with shield repelling technology!) and either looking or shooting at the enemy. Given that a laser can fairly easily be redirected to wherever you need it before it's focused in the turret, a laser turret on a boom is not very difficult nor heavy. The laser itself would simply be in the heart of your ship.

also, laser - based range finders won't work on the best sheilds, the ones that absorb. No light returns to the sensor, it's all absorbed!

Au contraire, it would work perfectly. The shield acts as a perfect mirror for EM. That's why it's so powerful. It does not need to absorb the incoming fire.

The only limiting factor is that for every 'push' of incoming weaponsfire, your shield gene's have to push back equally.

Partially true. Light does have momentum (where M_linear=m*v). However, the momentum of light is very low: a megawatt laser would produce a measly 1N of force.

I'm still investigating how effective the plasma would be for kinetics, but i'd need to plug the paper's equations into a math program and add some extra stuff to see what kind of results i get. My impression so far is that the plasma would still be pretty thin, very hot and still just a cloud of gas around you. And if the projectiles you fire aren't magnetic, it's not going to be stopped. And if it's magnetic, you'd probably cover your ship in a shower of micrometer dust at several km/s.

[thekillman]

Ok so the calculations are done, and quite frankly it does not look pretty.

First off, the amount of plasma you need. The oscillation frequency of the plasma is only dependent on a couple of constants and the amount of electrons per volume. Because of this, reflecting 10^6,5 hz light (uv/xray boundary) would require 3*10^29 electrons per cubic meter. This works out to about .2kg/m^3 of electrons alone.

Working out a hydrogen plasma, a 100m ship with 25m diameter, 1cm thick plasma layer, it gives me a whopping 46 tonnes of plasma. (the volume of the shield ~90m^3)

the amount of teslas needed to hold this together is a root function of the temperature. So, a 1000K shield needs 146 tesla and a 100k shield needs 46 tesla.

At 1000K the shield pressure is 8.686 GPa. (that is, 10^9 pascal). This is the same as the plasma pressure (for obvious reasons). at aforementioned 1cm thick plasma, one could apply ~9*10^10^7 N per meter of shield (for a random crossection, single side impact for obvious reasons) before it would break. This makes the structural integrity of the shield, if i'm not mistaken, about 36x greater than common steel. So it's safe to say that projectiles fired by a race with this kind of shield technology, would easily penetrate the shield. (modern submarine steel would be 7x as weak compared to the shield).

This shield would effortlessly reflect any kind of EM below Xray. I don't know how emissive a 1000K plasma shield would be. Comparing it to the contents and heat of a couple of lightbulbs, this 1000K (~600 degree Celsius) shield would probably barely glow. Noticeable with sensors, but not super intense to the eye. (assuming a perfectly black space).

Now another really annoying part: generating the shield. Based upon the work needed to generate the shield, you're looking at 766GJ.

To indicate, assuming a 1GJ reactor would thus need 766 seconds to erect the entire shield. (that's ~13 minutes). The field would be created and then rise in strength as the plasma is slowly injected. Thus, the EM threshold -what light it reflects- would slowly rise and the mechanical strength of the shield would slowly rise. Probably all linearly.

I am not sure what the power expenditure of the shield would be. You'd need superconducting materials to keep such a field active and running without needing ten more reactors to keep it active at all. You'd be leaking a bit of plasma so it needs to be resupplied, you'd need a way to scoop it back in or risk losing a massive amount of shield matter, reducing the longevity of the shield, every time you drop it (say, to conserve energy).
There are issues with having such a powerful shield near generic electronics, so everything would need to be properly shielded from EM. Sticking stuff through a 600-degree C shield is actually way easier than i imagined (though i think the electromagnetic interactions would probably be very bad for your boom), so some shielding would be required. Given the aforementioned coil:shield ratio of 10, there's good reason to believe you are carrying 460 tonnes of shield generator. Plus a 1GW reactor just for the shield.

[thekillman]

Two more things:

*the shield would be newtonian. That is, any action has an equal but opposite reaction. This means that momentum would be a surprising enemy. But, perhaps better than i can explain myself, Stardestroyer has an excellent view on this:
http://www.stardestroyer.net/Empire/...ds/Impact.html

It is widely assumed that if a sci-fi shield can withstand X joules of energy from a laser, it must be able to withstand X joules of energy from a physical impactor. However, this is not necessarily the case. As attractive as the simplistic numbers game is, if we apply a little bit of physics knowledge to the situation, we can see that if anyone were to build such a beast, the situation would be more complex than that.

So what would make physical impactors more dangerous? The answer to that question comes down to damage mechanisms. To put it simply, a physical impactor inflicts damage upon its target in a variety of ways. While an energy weapon will generally attempt to heat the target, thus permitting specialized one-dimensional defensive strategies, a large, fast-moving physical impactor presents a more complex threat:

Energy weapon (laser, phaser, turbolaser bolt, etc.):
Heats the target surface.

Physical impactor (asteroid, high-velocity ramming attack, hyper-velocity railgun, etc.):
Subjects the target to severe structural stresses, usually resulting in penetration. If it fails to penetrate, it pulverizes and/or vapourizes at the point of contact due to internal stresses and work-heating, thus producing a large cloud of high-temperature material at the target surface. This cloud heats the target surface through convection and radiation.

[ATTACH=CONFIG]40204[/ATTACH]

Let's assume that the rectangular assembly at left is a shielded starship (yes, I know, it looks cheesy, but please bear with me). The big brown rock at right is hitting the ship's shields, and it is being decelerated (hence the rightward force F being applied to the rock by the forcefield). For every action, there is an equal and opposite reaction, so there must be a counter-balancing force for that forcefield. A forcefield must be coupled to something, and in this case, it would obviously be the shield generator. Therefore, there is a leftward force F being applied to the shield generator (the blue square) in the middle of the ship. But the shield generator cannot move relative to the ship or it would be torn loose from its moorings, so its mounting brackets (the four red blocks) must each apply a rightward force 0.25F in order to hold the shield generator in place. These four reaction forces, in turn, push the entire ship to the left with force F, so the net result is to stop the impactor while accelerating the ship.

Are we clear on that? Now here's where it gets interesting: what if the shield generator's projected forcefield is easily strong enough to decelerate the asteroid to zero before the moment of impact, but the four little red blocks aren't strong enough to hold the generator in place? Guess what: the shield generator will be torn from its moorings, and the rock will slam into the ship. This is where momentum can rule over energy; a low-momentum, high-energy weapon such as a laser might not be as dangerous to a shielded vessel as a high-momentum, low-energy physical impactor. In this scenario, the potential points of failure are the shield generator itself, the points where it is mounted to the vessel, and the structure of the vessel itself. In other words, the mounting brackets, bolts, welds, shield generator internal mechanisms, shield generator forcefield strength, and all other connecting bits are parts of a chain through which reaction forces must go in order to make the end-to-end connection between the ship and the impactor. It can be thought of as a chain, and as in any chain, it is the weakest link that will cause your downfall.

As you can see, even if it was possible to build a deflector shield generator of virtually infinite strength, the overall effectiveness of the system would still be limited by good old-fashioned structural limits. Ultimately, the survivability of a shielded spacecraft against physical impacts could (and would, given sufficient shield strength) conceivably come down to a set of bolts holding a shield generator onto the ship's spaceframe. This example highlights the severe problem with most attempts to rationalize sci-fi technologies, which is that people tend to look for the strongest link in the chain, not the weakest link in the chain.

Or a TLDR:

Physical impacts and energy weapons should not be treated as functionally identical, particularly in terms of the relationship of energy to structural stress in the target. Collision physics are still ruled by Newton, and all of the deflector shields and fancy tricks in sci-fi will not prevent reaction forces from acting upon the physical structure of a target spacecraft.

Secondly: Failure mechanism.

This is more interesting, but it's basically the question "what if something goes wrong"?

The best case scenario for something going wrong is, interestingly, a general power failure. That is, the reactor provides no more juice. Aside from thermal problems that can still screw you over, the power to the shield won't matter that much. You're paying energy to maintain your losses (mass loss, thermal losses, potential shield integrity losses). Assuming the coils are superconducting (which is pretty much a necessity), the magnetic field could potentially be sustained for years. So the shield would remain up.

A worse case is shield penetration. It depends on the damage, but if a coil goes down, your magnetic bottle can locally weaken significantly. Given that we're talking about pretty high pressures, it's likely that a total (internal) containment failure would cause a small, high-powered plasma jet to cut into your ship. With luck, it's not very bad, you plug the hole with a secondary coil and it's fixed. Worse case, it's a full-on plasma leak and you're pumping your shield through the hole into the ship, causing catastrophic, total ship failure.

The bottle would need to be two-sided, so there may be generators required on the outside of the field. That, or maybe through electric currents and pinch effects, the plasma can maintain it's outer bottle by itself. Should the outer bottle fail, it would be a brief, barely visible but powerful explosion as the plasma is, well, de-bottled. It may be enough that in the event of a boarding, boarding parties and shuttles may be destroyed by forcibly "detonating" the shield. It would make the practicalities of surrender very difficult.

Dropping the shield is equally difficult. once you're acquired such a powerful magnetic bottle, there's simply no way you could store the energy again. This means the main generator would likely be shut down, and the ship would feed off the shield's stored power to drop it. Again, this would make boarding difficult, but also maintenance and rescue.

Now the above is true for the shield i calculated. far less powerful shield with far lower pressures would probably be not so catastrophic, but would also not be as useful.

Lastly: lasers with a higher frequency than the shield would not penetrate the shield like it's not there (as i previously believed), but rather would be absorbed and re-emitted. (like normal matter). So the aftermath of a lengthy battle might be scientifically-justified to have the entire ship bask in an intense glowing plasma halo, requiring potentially days to cool down to operational temperature. it would also add another failure mode, where the shield becomes so hot that the bottle is inadequate to contain it. It would start by bleeding off the hotter plasma, but probably end with a powerful bang (if the entire shield is too hot) or a plasma jet (as aforementioned) that cuts through the shield. This may be prevented by either surrendering, or detonating the shield.

[Gormagon]

What about seeking/guided ballistic weapon systems and magnetic/plasmagnetic/E5 shield? These include inert seeking missiles, chemical warheads, fission and fusion.

Edit- Whats the upward limit of chemical high explosive potential? For bombs and missile warheads?