Gateworld Virtual Fleet 4.0 - Discussion thread

[Gormagon]

How would I describe the deck setup to someone of an a O'Neill cylinder or Graham Baxter for civilian and military ships?...or are there readily available diagrams or pictures that offer a good, detailed visual of these devices?How does inertia work with spin gravity?

The guy i'm helping is having issues figuring out how to write in all the little specifics and details of centrifugal gravity, he needs to know where his people are in relation to where they are going and how they get there and such inside the ship.

Is it possible or necessary to build a spinning cylinder with decks setup like a sky scraper to work with inertia at first, pulling 'down' towards the engines, then when acceleration stops switch to spinning and have ether 1- utilities on the decks set up to change location easily and quickly, like on sliding rails or 2- Setup to work universally for easy access by people?

And my favorite, is it easier to just have a spin gravity area for exercise, sleep and/ or recreation (Like gardens, I foresee issues with zero G gardens and water) but the rest is in zero G?

[Gormagon]

Question: what form would entM transmissions take? Like could u theoretically have a FaceTime? Skype? Or would it be like morse code? Audio? Text? Would it be a data stream where u could send files? That was a question he posed.

[Gormagon]

Hadron or meson scanning, while of greater resolution again, require very high-energy output and ultratech equipment, and can easily be detected by an intelligent hull.
Neutrino scanning is stealthier and of lower energy, but generally of very poor resolution, and certainly not exempt from detection. Ultratech neutrino sensors are capable of reasonably good resolution, but are not widely available. Receivers for neutrino scanning can be bulky, although may be hidden effectively on or in moons or planets.

Might you have any additional information on these technologies?


Also 9/10 of a ship is supposed to be propellant....does this include fusion or Amat powered vessels? Are there any ways around this, any additional factors?

[thekillman]

How would I describe the deck setup to someone of an a O'Neill cylinder or Graham Baxter for civilian and military ships?...or are there readily available diagrams or pictures that offer a good, detailed visual of these devices?How does inertia work with spin gravity?

The guy i'm helping is having issues figuring out how to write in all the little specifics and details of centrifugal gravity, he needs to know where his people are in relation to where they are going and how they get there and such inside the ship.

Is it possible or necessary to build a spinning cylinder with decks setup like a sky scraper to work with inertia at first, pulling 'down' towards the engines, then when acceleration stops switch to spinning and have ether 1- utilities on the decks set up to change location easily and quickly, like on sliding rails or 2- Setup to work universally for easy access by people?

And my favorite, is it easier to just have a spin gravity area for exercise, sleep and/ or recreation (Like gardens, I foresee issues with zero G gardens and water) but the rest is in zero G?

I could answer that, but then i'd be dictating this page:

http://www.projectrho.com/public_htm...ficialgrav.php
So i'm just going to paste that link here.

And my favorite, is it easier to just have a spin gravity area for exercise, sleep and/ or recreation (Like gardens, I foresee issues with zero G gardens and water) but the rest is in zero G?

The difficulty with this is seals. If you want to have a habitable section partially in spin and partially not, then it induces a large amount of headaches for the designers to try and make that airtight.

That being said, spinning habitable sections and non-spinning, non-habitable sections are a good divide too.

Lastly on this subject, there's the thought of just taking zero g for granted. It causes some health problems, but unless these people absolutely want to live on a planet on some day, you may also just perpetually keep them in space. Their bodies would largely adapt (minus such things as giving birth). Though nobody really has tried to see what happens if you stay in space for more than a hundred or so days.

Question: what form would entM transmissions take? Like could u theoretically have a FaceTime? Skype? Or would it be like morse code? Audio? Text? Would it be a data stream where u could send files? That was a question he posed.

That depends on how often you want to reply on a given supply of entangled matter.

Morsecode or text files would have by far the most mileage. Remember that you can put thousands of text files on the same data storage as a single picture and hundreds of pictures for 1 movie.

However, the entangled matter would basically be one-use only bits. consider that 1 entangled atom can send an on/off signal (but only once), then a mole of matter (for sugar i believe that to be about a kilogram) you can send 10^27 (roughly) bits (and since a byte = 8 bits) or 10^26 bytes. I believe that's 100 tera tera bytes.

though i should note that current entangled matter consists of a few dozen to a hundred atoms max, and the trap for it, production and messaging systems would take much more mass than the actual matter.

Hadron or meson scanning, while of greater resolution again, require very high-energy output and ultratech equipment, and can easily be detected by an intelligent hull.

Mesons are Hadrons. Hadrons include protons and neutrons. So it's not really clear what this quote means.

Neutrino scanning is stealthier and of lower energy, but generally of very poor resolution, and certainly not exempt from detection. Ultratech neutrino sensors are capable of reasonably good resolution, but are not widely available. Receivers for neutrino scanning can be bulky, although may be hidden effectively on or in moons or planets.

Right now, every person on earth is bombarded by trillions and trillions of neutrinos. Maybe one or two atoms in your body are affected by this. Large neutrino detectors detect a dozen or so. While they would make for a great transmission medium (you could beam the internet right through the earth at a tiny signal loss) they are hard to detect and so you'd need a pretty intense neutrino source (e.g. the sun) and a pretty impressive neutrino detector to get any kind of detection going.

Thus, it's almost perfectly stealthy unless they carry impressive neutrino detectors. Because of their nature, line of sight is not an issue for either detectors or transmitters so you could just put up an array of detectors a mile underground and happily detect stuff.

Active scanning is something i don't really see the point of (maybe that's just me), the real bread and butter would be (passively) detecting the emissions of things like ship's reactors.

Also 9/10 of a ship is supposed to be propellant....does this include fusion or Amat powered vessels? Are there any ways around this, any additional factors?

3/4th. The maximum practical mass ratio is 3. (so 3x more ReMass than ship, making it 3/(3+1) = 3/4th is ReMass)

The problem is that the factor for the mass ratio is an Ln (natural logarithm) so it's effects on the deltaV of the ship are limited. Mostly, an under-efficient engine (specific impulse too low) will make the mass ratio skyrocket while an over-efficient engine does not massively reduce the mass ratio. So the best solution is an engine with Isp (specific impulse) in m/s, pretty close to the needed deltaV.

To give you an idea, this slightly ridiculous but entertaining breakdown might help:

http://what-if.xkcd.com/85/

[Gormagon]

Theoretically speaking, if you could build a stable tunnel to a planets core, could you create a magnetic field by inserting large amounts of molten metals and radioactive materials?

[Gormagon]

Oh, what about a break down of the destructive potential and various other effects of weapons like X-Ray lasers and proton beams in the hundreds of kilowatt-megawatt-gigawatt range with firing times lasting say.... half a second or more on hulls made of nanofibre composite, poly-ceramics, advanced polymers,and alloys of various metals, titanium, tungsten, ect, with varying thickness, or on planetary targets, stone, wood, dirt, nanocrete and steel, ect.

Basically, how much damage and devastation are we talking about?

[thekillman]

Oh, what about a break down of the destructive potential and various other effects of weapons like X-Ray lasers and proton beams in the hundreds of kilowatt-megawatt-gigawatt range with firing times lasting say.... half a second or more on hulls made of nanofibre composite, poly-ceramics, advanced polymers,and alloys of various metals, titanium, tungsten, ect, with varying thickness, or on planetary targets, stone, wood, dirt, nanocrete and steel, ect.

Basically, how much damage and devastation are we talking about?

Contrary to your earlier question, this is fairly simple to answer. (i'm still contemplating the other answer)



Weapons:
There are a lot of weapon types and a lot of effects. However, assuming it's purely for destruction and not for secondary effects, things get a lot simpler.

Weapons are mostly of two types: Kinetic and Directed energy.

Directed energy weapons add energy to the material (in some form) and thus, thermal effects are the primary damaging mechanism.

Kinetic Energy weapon have a non-negligible momentum (and usually a significant mass) and so have far more complicated reactions.

Materials:
Different materials react differently. However, we can group them according to their main describing theory.

Metals (modeled as springs: elastic behavior up till a certain point).

Polymers (modeled as spring, spring-dampener, dampener systems)

Ceramics (includes concrete, modeled as brittle).

composites (really complex).

Metals have good conductivity, but that's actually not what you want on your armor. I used to think it would work, but it's bad. If a ton of energy hits your ship, you want a tiny spot to be affected bad but the stuff protected by your armor should be unaffected. However, they're strong, easy to work with and abundant so it's common use. Expect high specific heat capacity, high conductivity. How well it withstands the attack depends on the exact metal, generally higher melting temperature and higher specific heat capacity (and higher strength) means better armor.

Each one of these properties has a failure mode. So if it's strong and has a high heat capacity but also high conductivity, your armor would be relatively unscathed while the engine behind it is rapidly overheating. If it's not strong enough the metal breaks under heat stresses. If it's too brittle your ship could tear in half in the blink of an eye. Etc.

Note that strength IS a function of temperature. Steel (and tungsten!, and any metal) only has a fraction of it's strength at high temperature. At 800 degrees C, steel is pretty soft.

Now metals have a pesky ability to turn charged particles into X-rays. So if you have a pure metal hull, striking it with, say, a proton beam would cook your crew when the rest of the ship is barely affected. Water has excellent neutron-absorbtion capacity, just as paraffin.

Polymers are unlikely to stand the test of time in space. The harsh radiation would just rapidly degrade these materials. Inside the ship it does work.

Ceramicsare generally brittle (e.g. concrete) and can break instantly via an avalanche effect within their crystalline structure. They can be extremely strong, extremely hard and extremely heat resistant so it's ideal armor material (and commonly used as such). However, the thermal stresses would wreck havoc on ceramics. So if it's used, it's likely as a set of really small individual tiles (e.g. the space shuttle).

Composites can be just about anything. For the purpose of a hull, however, this the most preferable system. E.g. a steel load-bearing structure with aluminium foam panels, boron carbide tiling etc.

Of course, as the complexity of the hull goes up so does the cost. So some governments may think that building 2 $2Bn ships with paperthin titanium hull and a big gun outweighs building 1 with thick armor etc.


Effects:


Imagine a laser striking a surface. It's weak. The outer (metal) hull heats a bit, and slowly it starts to drill as laserlight keeps hitting the surface. the metal melts, deforms. As the laser gets further, however, it heats the already hot metal more than it heats new metal. In stead of the laser properly drilling through the armor, it simply heats a spot, hoping the heat eventually kills the armor. (this is largely how the ABL works. The stresses on an ICBM in flight, combined with the weakened structure kills the missile).

Times ten. The laser strikes and flash-vaporizes the metal, the ionized metal tries to move away. Some of it succeeds, some of it is trapped in the laser light's power and gets pushed back into the hole. More and more metal vapor fills the cavity and the same problem occurs. a plasma blob in the armor is constantly fed heat, but now it's actually drilling.

Times ten. The laser strikes and flash vaporizes the metal. The plasma becomes a jet of hot matter blasting into the metal. However, an even larger portion of energy is stuck in the plasma and it starts to force itself out, digging a much bigger hole than needed and losing a lot of energy.

How to solve this? pulsed laser (in the order of milliseconds) light strikes the surface, flash vaporizes the metal, then there's a pause in which the plasma can dissipate and the next laser blast can hit fresh metal. For a while now, the effects will be roughly the same, just worse in magnitude.

Times one thousand. The laser light strikes, but the plasma's internal forces are nothing compared to the sheer energy being blasted into it. The plasma turns inwards, drills a hole as the laserlight heats it to thousands of degrees in milliseconds. Unless we're talking meters of armor (in which case i wonder what i'm even firing at), the plasma would torch through the ship as thermal stresses wreck the surrounding armor. Large sections of armor would buckle, but barely have the time to as the laser blasts trough the armor into the underlying segments. Any air is instant plasma and explodes through the weakened hull and interior of the ship (if the strength of the interior >> strength of the armor, it'll peel the ship open. else, it'll wreck the interior.)

Times one thousand. Gigawatt lasers are likely to have no meaningful effects beyond instantly vaporizing anything in it's path. It would just puncture straight through. Maybe with the exception of asteroids, but the effect would then roughly turn any matter into material for an explosion.


This is for fairly thin-walled constructs (which you'll find on ships).

Assuming somebody armed an asteroid, the failure mode becomes a mix between drilling, exploding and material failure.

[Gormagon]

• One 500 M.W X-ray laser battery forward firing; max firing cycle .2 second pulses, duration 1 second, 20 second cool down

Hows that sound? (We have very adequate heat disposal.)

What are realistic suggestions for velocity speeds and projectile weights for rail cannons? Or the....er...dispersion capacity of a magnetic/plasma shield?

[thekillman]

What are realistic suggestions for velocity speeds and projectile weights for rail cannons? /QUOTE]

Depends a bit on the exact execution. However, the projectile speeds are measured in km/s ranging from 3 to 7 km/s. Depending on how far into the future you get, it may rise to 10-20km/s but that's going to require quite the technology.

Coilguns do not really have an upper limit like that, other than "how long can you make your ship"

weights are in the low kilograms.


QUOTE=Gormagon;14248774] Or the....er...dispersion capacity of a magnetic/plasma shield?

That depends greatly. Unfortunately it would rely on thermodynamic equations to work it out properly. However, the properties would be largely the same: the shield has a certain reflection factor, heat conductance, heat storage and heat emission as well as a maximum temperature.

[Gormagon]

What about a fusion breeder reactor that uses 1- Lithium hydride or liquid lithium to breed fresh tritium? Which would be better? And T.D fusion compared to H3 and D fusion and the possibility of a multistage breeder reactor that uses both T.D and H3/D fusion ?


Well I know that X-ray lasers are only really useful in space, what about space use/atmosphere use/range of the beam for various other types like Infrared (I know U.S military is using IR atm.) and ultraviolet wavelengths, gamma, cosmic, also what about MASER type weapons as regards those factors?

Can thorium be used in nuclear batteries?

[thekillman]

One 500 M.W X-ray laser battery forward firing; max firing cycle .2 second pulses, duration 1 second, 20 second cool down

Looking some stuff up, you're not gonna get this without several hundred meters of accelerators for a free electron laser setup. There are different ways (and more compact!) to make X-ray lasers but they suffer from bad focusing (even more).

A 500 MW laser firing for .2 seconds means a 100MJ burst. .2 second pulses during 1 second suggests.
0: off
.2: on
.4: off
.6: on
.8: off
.10: on

so really 3 shots. (at t=0 it's off. At t=.2 it's been on for .2 seconds. it's off again till t=.4 then on till t=.6 etc.)

3 shots times 100 MJ = 300 MJ. Recuperation over 20 seconds means ~15MW of energy needed for the capacitor banks.

the efficiency for such a laser seems to be 33% (1/3rd) so a 300MJ cycle generates 600MJ of heat. Assuming it all is emitted during the 1 second of firing, that's 600MW of heat to deal with, meaning a significant amount of heat needs to be stored before being processed.

since water =4KJ/(kg*K), we heat it by 100 degrees we get 400KJ per kg*K.
At 600MJ that's ~3/2 * 1000 = 1200 kg of water to 100 degrees. In one second.


Assuming a hull made of nothing too exotic (e.g steel, titanium, aluminium) then the specific heat of the hull will be between 0.5 and 1 KJ/(kg*K).

Steel melts at 1400 degrees
Aluminium melts at 660 degrees
Titanium melts at 1670 degrees.

So the "melting capacity" is:

1400*0.45=630 kJ/Kg
660*0.91=600 kJ/kg
1670*0.45=751 kJ/kg

which is surprisingly close to eachother.

Thus, one hit from a beam (100MJ) can melt ( 100 000 /~660) = 151kg of aforementioned metals.

However, one metal is much denser than the other. Per volume, one kilogram of iron is three times smaller than a kilogram of aluminium and about half the size of a kilogram of titanium.

Fortunately, there's some proportionality between density and strength to ensure that per kilogram, the strength of these hulls are roughly equivalent (won't be off by orders of magnitude).

i don't really know the properties of such an X-ray laser. However, let's just assume the burn spot will be 1cm ~ .01m across. The area is then pi/4*d^2 = 7.8*10^-5m^2

Given that 151 kilogram of titanium is about 0.0314m^3 we can thus say that the penetration depth is 0.0314m^3/7.8*10^-5 m^2= 402m.

The problem is that this beam is hugely wasteful. A laser flies at the speed of light. So unless two ships drop out in spitting distance, a space battle starts whenever someone is confident enough to fire. And that can be from lighthours away. By the time they detect your shot, it's also there to hit or miss. Given the complexities of hitting (evading) targets with time lag at such distances, it's better to fire thousands of smaller shots.

[thekillman]

What about a fusion breeder reactor that uses 1- Lithium hydride or liquid lithium to breed fresh tritium? Which would be better? And T.D fusion compared to H3 and D fusion and the possibility of a multistage breeder reactor that uses both T.D and H3/D fusion ?

I have no clue. I'd expect the differences to be in engineering details not some fundamental difference.


He-3/D is slightly more energetic than T/D. Given that He-3 is a rarer isotope of He-4 and T is not even natural, i think it largely depends on availability.

Can thorium be used in nuclear batteries?

Every element that decays with electron or positron radiation works in a nuclear battery.

[Gormagon]

What about UV vs IR spectrum of laser?

Also I have been trying to research information about specific numbers regarding radiation exposure in deep space and the effects of solar storms in order to better design the shielding systems. How does a dispersion rate of 850 mSv per minute sound? How would that relate to laser and particle weapons?

[Gormagon]

Additional, in a futuristic nuclear powered world via nuclear batteries, fission, fusion, ect, I'm having trouble figuring out exactly how to regulate the issues. When everyone started owning cars they added licensing and registration, but if someone gets drunk at the wheel of a car and crashes they will not irradiate the city like a crashed space vessel would if the rector breached upon impact.

I'm thinking space police and satellites capable of handling the situation with grapples and/or weapons.

Plus space licences for varying types of space ship, for instance is your ship powered by Amat catalyzed fusion or a simple nuclear battery? There should be different grades of license just like today.

Registration of your ships details and a location beacon.

Limiting the type of reactors available for civilian use. I'm thinking various nuclear batteries and thorium and chemical rockets for the most part. Only larger well trusted corporations and the government can have certain higher technologies, or afford to use them at all.

Its not like we are trying to make space mini vans though.

Cars today are getting so complex and computerized you can only do basic maintenance on them pretty much, or at least your average person, do you think making the reactors not accessible to the lay person but only by officials at regulated space stations is a feasible idea when you need reactor maintenance or refueling? Like, if someone else tries to access it an alarm signal is sent to to nearest police base?

Also we are using EM launchers to get inert cargo into orbit, but people are so expensive. How plausible is surface to orbit traffic akin to air travel today?

Speaking of radiation spills, we were considering a company that deals specifically with such issues, a clean up company that uses various microbes and radiation absorbing plants to take care of the issues, and the recycling of 'nuclear waste' if it can still be called that, into breeder reactors and such.

[thekillman]

What about UV vs IR spectrum of laser?

Also I have been trying to research information about specific numbers regarding radiation exposure in deep space and the effects of solar storms in order to better design the shielding systems. How does a dispersion rate of 850 mSv per minute sound? How would that relate to laser and particle weapons?

1: The shorter the wavelength the more energetic the photon is.

2: no clue. Radioactivity isn't exactly my favorite subject. However, there's this: https://xkcd.com/radiation/

Additional, in a futuristic nuclear powered world via nuclear batteries, fission, fusion, ect, I'm having trouble figuring out exactly how to regulate the issues.

Something similar (broadly speaking) exists today in the form of nuclear technology and commercial aviation.

Today, almost all the commercial reactors in the USA are owned by private companies, and nuclear industry as a whole has far greater private participation, and less concentration, than any other country.
Yet, the government remains more involved in commercial nuclear power than in any other industry in the USA. There are lengthy, detailed requirements for the construction and operation of all reactors and conversion, enrichment, fuel fabrication, mining and milling facilities. The review process preceding the construction of new reactors can take 3-5 years. The US government, through its own national research laboratories and projects at university and industry facilities, is the main source of funding for advanced reactor and fuel cycle research. It also promises to provide incentives for building new plants through loan guarantees and tax credits, although owners have to raise their own capital. US domestic energy policy is also closely linked to foreign, trade and defence policy on such matters as mitigating climate change and nuclear non-proliferation (of weapons).
As of late 2013, the Nuclear Regulatory Commission (NRC) was reviewing nine applications for combined construction and operating licences (COLs) to build 14 new nuclear reactors, as well as three design certification applications for new reactor types (EPR, ESBWR & APWR) and two design certification renewals (both ABWR). The NRC’s FY 2014 budget for oversight of the 100 operating power reactors was $1055 million, including six reviews of extended power uprate requests (and eight others) and 10 licence renewal applications. The budget includes nuclear materials and waste safety.

World Nuclear Association

Aviation is more privatized, but still faces strict rules and regulations, tight control over permits and licences and a strong drive to be better. Look at Malaysian Airlines: two unrelated, unforseeable accidents later and their stock dropped 60%. A spacecraft crash would be a PR nightmare that could close an entire company.


as to what form this takes: it's likely that indeed, access to more powerful technologies require more extensive testing and more permits. Even a basic nuclear battery would require permits for the acquiring, processing and "burning" of radioative matter. Note that to properly run such a battery you need pretty intense radiation, so per definition it's dangerous. NASA for instance uses plutonium in it's Curiosity.

Depending on how lax or strict the world has become on nuclear technology, it could either be widespread or very limited.

It depends on what kind of companies you (want to) have, before you can say what engines they'd use. A nuclear engine is powerful, but it would also require a few days of power up and power down. It's not something you'd use for an orbit-to-orbit satellite repair service.

For a space-based shipping company, there's two routes to take: short-time, high expense trips or long-time, low expense trips. ultrabudget companies would use e.g. Solar Moths (check the Atomic Rocket page) to coast around and get to their destination at minimum costs. It could easily be underway for months.

For large freight operations nuclear is pretty much a must. (talking multi-tonne here). Not that chemical can't be done, it can. But if one company can use nuclear, it'll outcompete all others. It would require extensive licensing not just to get the fuel in your ship, but also to get a ship designed with such a powersource, the crew to handle it and the licensing to repair and maintain it. It also means that typical "ragtag crew of misfits" is something you'd never see on any space vessel.

Policing is something i'm not really sure of. I think you'd simply be looking at remote-operated drone craft. however, maritime pilots (or well, equivalents thereof) would operate drone craft with powerful engines to say, intercept a derelict vessel and redirect it. Note that in space, physics rules in it's raw form and so, if there's not enough room to take on refugees, there really is no room for refugees, no matter how much you want it. It's not seatravel where there's infinite air and water.

Cars today are getting so complex and computerized you can only do basic maintenance on them pretty much, or at least your average person, do you think making the reactors not accessible to the lay person but only by officials at regulated space stations is a feasible idea when you need reactor maintenance or refueling?

This is a non-issue. A nuclear reactor is something only operable and accessible by qualified personnel. Especially since any meaningful engineering (usually coupled with control) would have to be relatively close to the reactor and encapsulated in it's protective shell. You won't get close to the reactor without the right access. Oh and i don't think a layperson can remotely understand what it would require to operate one. Most advanced control stuff is built to have maximum control. This usually kills off any lay-person accessibility. Hell i've stood at the control operations of a (gas)power plant (didn't touch any buttons) and i can tell that it's complex, and no matter how much stuff you look up it's not obvious to run one.

Also we are using EM launchers to get inert cargo into orbit, but people are so expensive. How plausible is surface to orbit traffic akin to air travel today?

It'll be more like the early days of commercial air flight. It'll always be expensive to launch someone into orbit. The energy requirements are simply too much.

we were considering a company that deals specifically with such issues, a clean up company that uses various microbes and radiation absorbing plants to take care of the issues, and the recycling of 'nuclear waste' if it can still be called that, into breeder reactors and such.

Too niche. (unless it's highly dystopian). A nuclear company would likely be a total-solution company, e.g. providing the fuel, the reactor and (major) maintenance, as well as cleanup. However, some form of decontamination would likely be available to major space stations.


Note that a nuclear ship would spew out radiation, making dealing with radiation et all a fairly common business.