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Old 08-04-2020, 01:45 PM   #41
Say, it isn't that bad!
 
Join Date: Dec 2013
Default Re: In which I post about a TL9 solar system

Quote:
Originally Posted by Anthony View Post
Well, some of that has to do with scale. Mass requirements for mass shielding vary with surface area, mass requirement for electromagnetic shielding (applies to both magnetic shields and electrostatic shields) vary with diameter, so electromagnetic shielding wins for sufficiently large scale vessels and habitats.
Edit: Post struck as super-science until further information.

What Size Modifier would "sufficiently large" be, in this context? I'm going to guess SM+13, so I can do a preliminary write-up.

Need some sort of write-up of electromagnetic/electrostatic shielding, so starting from Force Screen: Each TL adds/subtracts the equivalent of one SM from a ships' armour, so a TL9^ Force Screen for a SM+15 ship or station would be 200 dDR.

Energy is a -50% modifier for Force Screen, which limits a Force Screen to protecting against "beam weapons (or energy melee weapons like force swords), radiation, and the burning damage of nuclear or antimatter blasts." It seems reasonable that this would make its 200 dDR also work as unhardened PF. Restricting it to just radiation sounds like a -80% modifier, and at this point we can call it an "Electromagnetic or Electrostatic Shield" and remove the super-science modifier, and call it TL9.

So: Force Screen (radiation only -80%), TL9^.

Electromagnetic Shield (TL9^) [CORE!]
This system generates a protective electromagnetic field around the entire vessel – it protects all hull sections, not just the one it is installed in. It is rated for the (p. B436) anti-radiation protection factor that it provides. The table shows the field’s PF and the cost per (high-energy) system. Apply the electromagnetic fields' PF first, then any PF from non-empty ship systems.
A spacecraft may combine multiple electromagnetic shield sections into a single system; in this case, add their PF together to get the total PF. You may not combine electromagnetic shields and electrostatic shields. Electromagnetic shields may be light or heavy:
Light Electromagnetic Shield: A relatively inexpensive design; use the listed PF.
Heavy Electromagnetic Shield: A high-power field; it may function as a light field, or it can increase its PF by +50% by using a second Power Point to reinforce the field.
The field only provides protection while powered up.
Code:
SM              +13     +14     +15 Edit: There is probably insufficient power at SM less than +15.
PF              50      100     200 Edit: Electromagnetic fields work off the radius, not the surface area.
Cost
Light Shield    $100M   $300M   $1B
Heavy Shield    $300M   $1B     $3B
Electrostatic Shield (TL9^) [HULL!]
This system generates a protective electrostatic field around the entire vessel – it protects all hull sections, not just the one it is installed in. It is rated for the (p. B436) anti-radiation protection factor that it provides. The table shows the field’s PF and the cost per (high-energy) system. Apply the electrostatic fields' PF first, then any PF from non-empty ship systems.
A spacecraft may combine multiple electrostatic shield sections into a single system; in this case, add their PF together to get the total PF. You may not combine electromagnetic shields and electrostatic shields. Electrostatic shields may be light or heavy:
Light Electrostatic Shield: A relatively inexpensive design; use the listed PF.
Heavy Electrostatic Shield: A high-power field; it may function as a light field, or it can increase its PF by +50% by using a second Power Point to reinforce the field.
The field provides one-half its usual protection when powered off.
Code:
SM              +13     +14     +15 Edit: There is probably insufficient power at SM less than +15.
PF              37.5    75      150 Edit: Electrostatic fields work off the radius, not the surface area.
Cost
Light Shield    $100M   $300M   $1B
Heavy Shield    $300M   $1B     $3B
Edit: Some edits made in the last five minutes.

Last edited by Say, it isn't that bad!; 08-04-2020 at 06:47 PM.
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Old 08-04-2020, 02:21 PM   #42
AlexanderHowl
 
Join Date: Feb 2016
Default Re: In which I post about a TL9 solar system

That is still a superscience system because you are talking about an electrostatic system capable of deflecting 100+ GeV intensity relativistic iron nuclei. For a comparison, a TL9 fusion reactor would likely have electromagnetic or electrostatic fields that are barely capable of containing 20 MeV particles, and they have the advantage that they only have to protect a few square meters. For a system to cover the hundreds of thousands of square meters of a SM+13 system would require TW of energy (around 10 MW per square meter). By comparison, a generous interpretation of a SM+13 fusion power plant has it producing 40 GW (20 GW per power point), which would be around 5% the required energy levels.
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Old 08-04-2020, 02:52 PM   #43
Anthony
 
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Default Re: In which I post about a TL9 solar system

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Originally Posted by Flyndaran View Post
Any idea on where that break point would lie?
Depends on superconducting tech and the field strengths you're willing to tolerate in areas that might include personnel or other systems that might object to strong magnetic fields. With ultratech superconductors, probably a habitat radius in the hundreds of meters.
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Old 08-04-2020, 02:55 PM   #44
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Default Re: In which I post about a TL9 solar system

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Originally Posted by AlexanderHowl View Post
That is still a superscience system because you are talking about an electrostatic system capable of deflecting 100+ GeV intensity relativistic iron nuclei. For a comparison, a TL9 fusion reactor would likely have electromagnetic or electrostatic fields that are barely capable of containing 20 MeV particles, and they have the advantage that they only have to protect a few square meters. For a system to cover the hundreds of thousands of square meters of a SM+13 system would require TW of energy (around 10 MW per square meter). By comparison, a generous interpretation of a SM+13 fusion power plant has it producing 40 GW (20 GW per power point), which would be around 5% the required energy levels.
So a thing I forgot to factor in is that, since electromagnetic/electrostatic fields are measured by diameter rather than surface area, increasing the SM by +1 should increase the PF by +100%, not +50%.

It doesn't need to bring them to a halt, just shove them aside a bit. So, math.

Let's say 400,000 square metres, which gives us 632m of room to play with. That's not going to work with a SM+13 hull.

Alright, SM+14, we have 1,264m of room to work with, and a 700m hull. That gives us a radius of 632m to avoid 350 metres. A little trigonometry says that's a 33.63 degree deflection, and we need 55 GeV to deflect it.

Still not enough. SM+15, we have 2,528m of room, and a 1,000m hull. We've got a radius of 1,264m, and need to adjust by 500m. 40 GeV to deflect it, and a single power point (judging by the beam output of a Major Battery) is probably 3TJ (1TJ output at 33% efficiency). With an increase of in diameter 4x over SM+13, we'd need 4TJ.

I think that's "close enough for napkin math"; with that, electromagnetic / electrostatic shielding is restricted to SM+15.
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Old 08-04-2020, 03:08 PM   #45
Anthony
 
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Default Re: In which I post about a TL9 solar system

Quote:
Originally Posted by Say, it isn't that bad! View Post
So a thing I forgot to factor in is that, since electromagnetic/electrostatic fields are measured by diameter rather than surface area, increasing the SM by +1 should increase the PF by +100%, not +50%.
The PF model doesn't make sense for magnetic shielding. Electromagnetic shielding is much more like DR -- it has near total effectiveness against the particles it can stop (charged particles with an energy of less than X per unit charge) and nearly useless against the rest (uncharged particles, charged particles with energy above X). You can convert it to a PF for particular sources if you know the mix of particles involved, but it will be very specific to a single source (radiation protection varies appreciably based on what you're shielding against for mass-based shielding too, but it at least resembles exponential decay when dealing with gamma rays or cosmic ray primaries).
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Old 08-04-2020, 03:14 PM   #46
Say, it isn't that bad!
 
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Default Re: In which I post about a TL9 solar system

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Originally Posted by Anthony View Post
The PF model doesn't make sense for magnetic shielding. Electromagnetic shielding is much more like DR -- it has near total effectiveness against the particles it can stop (charged particles with an energy of less than X per unit charge) and nearly useless against the rest (uncharged particles, charged particles with energy above X). You can convert it to a PF for particular sources if you know the mix of particles involved, but it will be very specific to a single source (radiation protection varies appreciably based on what you're shielding against for mass-based shielding too, but it at least resembles exponential decay when dealing with gamma rays or cosmic ray primaries).
Edited for clarity:

Unfortunately, I'm not aware of any GURPS mechanic for "Radiation Damage Resistance", so I have to work with what I have. :)

There's a limit to how many things I want to invent in this thread, and fundamental mechanics are well outside that limit.

OTOH, if someone has a combination of enhancements and limitations that makes PF work like DR, feel free to post it. :) As long as it doesn't involve hand-waving like Cosmic, I'll probably use it.

I could apply a "Charged Particles Only" limitation to it; it wouldn't change the cost, since it's already -80%.
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Old 08-04-2020, 03:22 PM   #47
AlexanderHowl
 
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Default Re: In which I post about a TL9 solar system

It would still be superscience. Magnetic and static fields are linear from the source, which would be the hull of the ship, so it would have to be a surface feature added to armor. If you tried to extend from any single system, you would end up electrocuting/irradiating everyone you are trying to protect because the field strength would need to be absolutely immense.
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Old 08-04-2020, 03:38 PM   #48
Say, it isn't that bad!
 
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Default Re: In which I post about a TL9 solar system

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Originally Posted by AlexanderHowl View Post
It would still be superscience. Magnetic and static fields are linear from the source, which would be the hull of the ship, so it would have to be a surface feature added to armor. If you tried to extend from any single system, you would end up electrocuting/irradiating everyone you are trying to protect because the field strength would need to be absolutely immense.
That... is a very good point.

Placing it on armour wouldn't help, either; magnetic and static fields of that magnitude can't really be kept away from areas you don't want magnetized or... staticified? by a simple layer of matter.

However, going from the picture presented in the first NASA pdf I posted on electromagnetic/electrostatic radiation shielding:

https://ntrs.nasa.gov/archive/nasa/c...0090022229.pdf

A *rotationally-offset system of three rings may work; each ring would contain coils/other electronic systems to project an electromagnetic or electrostatic field, designed so that it does not reach the ship's hull. Interference from the rings would be minimized by designing the rings as a single system. Multiple ring "sections" would increase the thickness of the rings.

* So your drive does not vaporize your shielding system.

Edit: Alternately, it may need a gap at the back so the drive plume can get through, which would mean it doesn't protect the rear hull.

Last edited by Say, it isn't that bad!; 08-04-2020 at 03:45 PM.
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Old 08-04-2020, 04:05 PM   #49
AlexanderHowl
 
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Default Re: In which I post about a TL9 solar system

The problem with that design is that the fields are not unidirectional, the interior of the rings will experience electromagnetic/electrostatic forces comparable to the exterior (it would actually have to be more intense than the armor version, because the rings would not already cover the entire ship). Just from looking at the design, it would also interfere with the exhaust of the engines, as they are a positively charged plasma from being heated to over 10,000 K by the fusion reactor. The heat from the redirected exhaust would cause the superconductors to melt long before they roasted the people in the spacecraft, but it would probably subject them to the equivalent of 1,000 rads per hour of proton radiation until the superconductors melted (which would be worse than the GCR that they are protecting them from, which only does 0.006 rads per hour).

If you are already doing SM+13 or larger spaceships, you probably have enough mass shielding to reduce radiation exposure to 5 rads per year, which is acceptable, so the active shielding is likely unnecessary and/or actively dangerous. Now, this is realistic for a TL9 society with a developed space infrastructure, they have to go big or stay home, because such activities are only affordable through massive economies of scale at TL9-. For interplanetary travel, I imagine that a realistic TL9 setting would have thousands of SM+13 or larger spaceships traveling between colonies, with a combined economic impact of tens of trillions of dollars per year. Of course, a developed TL9 society with a population of 10 billion people (assuming that the Earth is actually an Affinity 10 world for humanity if managed properly), the Earth's economy alone would be $602 trillion per year.
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Old 08-04-2020, 04:31 PM   #50
Anthony
 
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Location: Berkeley, CA
Default Re: In which I post about a TL9 solar system

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Originally Posted by AlexanderHowl View Post
The problem with that design is that the fields are not unidirectional, the interior of the rings will experience electromagnetic/electrostatic forces comparable to the exterior (it would actually have to be more intense than the armor version, because the rings would not already cover the entire ship).
That's fairly irrelevant, as the portion of the field that is actually protecting the ship is actually much much larger than the rings generating the field, and because it's a dipole field, the exhaust is coming out the end of the dipole (you actually need to have an uninhabited hole in the middle, because, while some particles will just be deflected away, others get funneled down the middle of the dipole). Of course, if you have spin gravity you don't want people in the middle anyway...
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