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Post by Pttg on Jun 5, 2018 20:42:40 GMT
Currently, the game doesn't really simulate neutron flux from nuclear explosions. Lacking atmospheric shielding and considering the difficulty of protecting a ship's crew from radiation, the effective kill distance for a nuclear missile far exceeds the distance at which the missile will significantly melt the whipple.
Obviously it is very difficult to simulate the received momentary radiation of a crew, and even moreso to simulate the immediate effects of radiation poisoning. However, the lack of simulation does hide the serious effect on tactics we would see. An unshielded enemy ship can simply be irradiated by a single warhead well outside of most defensive ranges, and taken whole for its valuable elements. Even if you do intend to destroy a ship, no missile should ever be destroyed by an incoming projectile so long as it's safely away from the launching ship; a ship close enough to fire upon a missile is almost certainly close enough to bombard with radiation and then be destroyed at leisure.
The adequate defense against such attacks seems to me to be interceptor drones -- simple, cheap shrapnel drones that intercept incoming missiles outside of the irradiation zone. The countermeasure is a kind of stealth. You do not need to hide that your missile exists, but if you blur or conceal its exact trajectory, you may be able avoid interception.
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Post by jtyotjotjipaefvj on Jun 5, 2018 21:20:24 GMT
Coating the crew modules (or whole ships) with ablative Li-6 might be a decent defence against neutron bombs. You wouldn't need to worry too much about vaporization due to heating either since you'd likely need to block just a few instantaneous neutron flashes, so a solid block of lithium should be good enough to stop a couple of nukes.
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Post by AtomHeartDragon on Jun 13, 2018 18:23:33 GMT
Would replacing all the spurious cooks, yeomen et.al, along with associated CM mass with equivalent mass of bulk neutron shielding provide adequate protection?
Asking for a friend.
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Post by Rocket Witch on Jun 19, 2018 4:37:39 GMT
a solid block of lithium should be good enough to stop a couple of nukes. Might even be able to foam it to act additionally as a deep kinetic barrier, if that wouldn't negatively impact the neutron absorption. Should be something like 107 kg/m 3 at 80% porosity, which is comparable to silica aerogel. Would replacing all the spurious cooks, yeomen et.al, along with associated CM mass with equivalent mass of bulk neutron shielding provide adequate protection? Asking for a friend. Each person added to a CM made of 1mm RCC adds 2.63t. There are a minimum of 7 command personnel, whom if removed would give 18.41t over to added protection of the CM. For that mass a Li-6 coating thickness of approximately 9cm can be spread over a 40-person CM, which will bring a 1MW radiation hazard down to just 1aW. So yes. |
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Post by AtomHeartDragon on Jun 19, 2018 18:44:08 GMT
I wonder if neutron activation of CM would be very bad - if not, it could be possible to further radiation harden them by only shielding battle stations and electronics.
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Post by Anon1 on Jun 30, 2018 3:15:03 GMT
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Post by Enderminion on Jul 2, 2018 21:20:28 GMT
Li-6 also turns to H-3 when it eats a Neutron, so extra radioactives for funs!
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Post by Rocket Witch on Jul 2, 2018 22:28:28 GMT
I'm trying to understand the logic that 9 cm of lithium-6 is supposed to stop 1 MW of fast neutrons. I went by game values, slapping Li-6 onto a reactor's neutron reflector and noting the change in the 'radiation hazard' field. At one point CDE was updated to account for gamma rays, at least to some extent, so the initially doubtful idea of covering everything in Li-6 became easier to take for granted when it continued to work largely as well as it did before. |
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Post by apophys on Jul 9, 2018 6:00:05 GMT
Foaming your mass and decreasing its density, decreases the number of atoms available to capture incoming neutrons. It should be fine if you increase the thickness proportionally to the density decrease, so you end up with similar mass as un-foamed. The point of the foaming was to have the material do double duty as the stuffing in a stuffed whipple shield, for superior kinetic resistance against small projectiles compared to a monolithic block. Nice. So to be realistic, you'd need mass and/or distance shielding behind the lithium to deal with the generated gamma rays. Considering that the generated gamma ray can probably be in any direction, not necessarily the direction the neutron was moving in, you may get significant overall benefits with some distance shielding. Maybe a more compact option would be to thermalize neutrons, and then use boron for absorption of thermal neutrons? Sadly, CoaDE doesn't model that interaction properly for rad shielding outside of reactor cores. Reminds me of borated polyethylene used for neutron shielding irl.  It may be worth combining these techniques, with a layer of lithium just under the whipple shield, bulk armor and propellant tanks underneath, and a boron or boron carbide crew module. |
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ghgh
Full Member
Still trying to make kinetics work.
Posts: 136
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Post by ghgh on Jul 9, 2018 20:12:09 GMT
Would replacing all the spurious cooks, yeomen et.al, along with associated CM mass with equivalent mass of bulk neutron shielding provide adequate protection? Asking for a friend. Would make sense if cook/logistics officer were rolled into one. The captain and first mate can probably double as yeomen since clerical work will be little more than checking the email (unless you plan on launching a rocket filled with documents on an intercept course). |
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Post by AtomHeartDragon on Jul 18, 2018 18:06:39 GMT
Nice. So to be realistic, you'd need mass and/or distance shielding behind the lithium to deal with the generated gamma rays. Considering that the generated gamma ray can probably be in any direction, not necessarily the direction the neutron was moving in, you may get significant overall benefits with some distance shielding. Maybe a more compact option would be to thermalize neutrons, and then use boron for absorption of thermal neutrons? Sadly, CoaDE doesn't model that interaction properly for rad shielding outside of reactor cores. Reminds me of borated polyethylene used for neutron shielding irl. Put crew in small heavy metal tubs during combat? IIRC gammas tend to not transmute stuff so you don't need a lot of mass around entire ship or even entire crew module - just individual crewmembers' stations and sensitive equipment. And boron is also part of several good anti-kinetic materials. Beryllium is also potentially interesting for structural stuff. Would replacing all the spurious cooks, yeomen et.al, along with associated CM mass with equivalent mass of bulk neutron shielding provide adequate protection? Asking for a friend. Would make sense if cook/logistics officer were rolled into one. The captain and first mate can probably double as yeomen since clerical work will be little more than checking the email (unless you plan on launching a rocket filled with documents on an intercept course). Actually I would imagine the most minimalistic autonomous combat spaceship (just fixed forward firing weapons and/or fire-and-forget missiles / automated CIWS) might possibly require crew of as little as three (definitely not twenty six): - Pilot/astrogator/captain rolled into one (also responsible for firing at the enemy, since the weapons are fixed or autonomous)
- Engineer (maintaining hardware and possibly software)
- Doctor/Medic (maintaining wetware - AKA self and the other two)
I'm trying to understand the logic that 9 cm of lithium-6 is supposed to stop 1 MW of fast neutrons. I went by game values, slapping Li-6 onto a reactor's neutron reflector and noting the change in the 'radiation hazard' field. At one point CDE was updated to account for gamma rays, at least to some extent, so the initially doubtful idea of covering everything in Li-6 became easier to take for granted when it continued to work largely as well as it did before. It probably doesn't account for radiation emitted by normally non-radioactive parts like armour and radshields.
Hell, you probably won't be able to just work with just a tiny shadow shield when flying in formation (and dodging wildly).
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