Nuclear Missiles and Cumulative radiation effects

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PsiTraveller
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Nuclear Missiles and Cumulative radiation effects

Postby PsiTraveller » Sat Nov 20, 2021 1:55 am

SirGamingScotsman has a thread about shipo scale radiation damage. It got me to thinking and I did not want to hijack his thread.

Do nuclear missiles create a radiation exposure per missile or per salvo?

If I shoot 3 nuclear missiles and they all hit a ship, is the radiation damage rolled once? or three times, or is it multiplied by the Effect the same way damage is? If a single missile hits I am assuming it gets to do damage and radiation effect.

Example ship: 400 tons. The ship has 4 hardpoints and has 2 Particle beam barbettes and 2 triple mount missile turrets. Nuclear missiles in all 6 missile launchers.

When the ship attacks the 2 particle beam weapons will roll their damage separately and also their radiation damage. This radiation will be protected against by the hull of the enemy ship. Radiation damage has been scaled back to 2D X 60 instead of 2D X 100 in the 2022 update.

If our 400 ton ship launched a single nuclear missile and it hit the target it would roll an additional 2D X 60 for rad damage. If the ship launched 6 missiles and they all hit the damage is that of a single missile multiplied by the Effect of the attack roll (pg 162 of the pre 2022 Core book, not sure if this rule has been changed in the 2022 update, up to the number of missiles in the salvo.)

Is the radiation damage also multiplied? if so, ouch, and if the damage output is aided by extra missiles, why isn't the radiation? I don't want to get into a scenario where small ships have to roll handfulls of dice to calculate exposure, but on the other hand, radiation weapons are meant to be a nasty threat, and why they are banned from use inhabited planets (pg 31 of Highguard)

And another question: How fast does the cumulative radiation effect kick in. Cunningrat pointed out that a person in a ship with a TL 12 vac suit is protected against 590 points of radiation. With the radiation exposure chart. With a 12 on the damage roll this means 130 points of radiation get through to a person. This is 1D damage and -1 to all checks. But in a protracted battles a character may take several hits, putting their cumulative total over 151, which might give them a -1 END permanently. How fast does the cumulative effect kick in?
cunningrat
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Re: Nuclear Missiles and Cumulative radiation effects

Postby cunningrat » Sat Nov 20, 2021 6:53 pm

PsiTraveller wrote:
Sat Nov 20, 2021 1:55 am
Is the radiation damage also multiplied? if so, ouch, and if the damage output is aided by extra missiles, why isn't the radiation? I don't want to get into a scenario where small ships have to roll handfulls of dice to calculate exposure, but on the other hand, radiation weapons are meant to be a nasty threat, and why they are banned from use inhabited planets (pg 31 of Highguard)
I think the radiation output should be 2d6 x 60 per missile in the salvo, with Effect not entering into it. The damage the missiles do is both dependent on where the missiles hit (which is Effect in game terms) and the number of missiles in the salvo: that is not the case for radiation. A missile can hit anywhere and still deliver its full dose of radiation.

IMO, the radiation output should also resolve each 2d6 roll as a separate attack (with Rad resistance applying to each roll). My reasoning is that both Radiation damage and missile damage have been scaled back with the 2022 update, to make them slightly less deadly. Before the update, with both Radiation and missiles you were one high roll away from a TPK. I think radiation damage from missiles should follow the spirit of those changes.
PsiTraveller wrote:
Sat Nov 20, 2021 1:55 am
But in a protracted battles a character may take several hits, putting their cumulative total over 151, which might give them a -1 END permanently. How fast does the cumulative effect kick in?
Having taken a shallow dive into how Acute Radiation Sickness actually works, and what symptoms/conditions that "-1 END permanently" is supposed to represent, I would say that the cumulative effect kicks in within 1 week. Not during the battle, but soon afterwards.

Also, I would like to note that Mongoose radiation rules are significantly more lenient than the real world. In the real world, 250 to 500 rads have a 50% chance of killing you. 1000 rads have a 100% chance.
DickTurpin
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Re: Nuclear Missiles and Cumulative radiation effects

Postby DickTurpin » Mon Nov 22, 2021 2:09 am

These answers are based on the current rules, the new book may change things. I would treat the radiation damage exactly the same as the weapon damage, roll the damage for one missile, subtract the radiation resistance for the hull (500 normally, 1,000 with Radiation Shielding) then multiply the remainder by the effect of the attack (minimum x1 for effect zero as a personal rule clarification) up to the total number of missiles in the salvo.

My reasoning is as follows: 1) Simplicity; keep the rules consistent. 2) Reduce RADS by hull; the missiles spread out so many different locations are hit. Combining the RADS before reducing them for hull would make sense only if every missile struck the same location. 3) Multiply by the effect; in missile combat the effect represents how many of the missiles actually hit the target. Multiplying by the salvo size only makes sense if every missile strikes the ship.
Condottiere
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Re: Nuclear Missiles and Cumulative radiation effects

Postby Condottiere » Mon Nov 22, 2021 1:11 pm

Speaking cumulative radiation effects, isn't that an issue with being outside the protective shield of the Terran atmosphere in general?
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NOLATrav
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Re: Nuclear Missiles and Cumulative radiation effects

Postby NOLATrav » Mon Nov 22, 2021 3:29 pm

Condottiere wrote:
Mon Nov 22, 2021 1:11 pm
Speaking cumulative radiation effects, isn't that an issue with being outside the protective shield of the Terran atmosphere in general?
Presumably hulls with Armor 0 or greater are robust enough to withstand common solar radiation and micrometeorites. It’s the solar flares (and nuclear weapons) that get you.
Condottiere
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Re: Nuclear Missiles and Cumulative radiation effects

Postby Condottiere » Tue Nov 23, 2021 11:48 am

The problem with armour factor zero, is, that it takes up no volume.

As in implying paper thin.
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NOLATrav
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Re: Nuclear Missiles and Cumulative radiation effects

Postby NOLATrav » Tue Nov 23, 2021 6:23 pm

Condottiere wrote:
Tue Nov 23, 2021 11:48 am
The problem with armour factor zero, is, that it takes up no volume.

As in implying paper thin.
Agreed, there is a hole there. I recall MegaTraveller stating a basic hull had an unintuitive armor factor of 40, which was the minimum for safe transit in a solar system. Don't recall if that required volume or not.
Galadrion
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Re: Nuclear Missiles and Cumulative radiation effects

Postby Galadrion » Wed Nov 24, 2021 7:36 am

NOLATrav wrote:
Tue Nov 23, 2021 6:23 pm
Don't recall if that required volume or not.
It did - because that volume was a factor in the hull mass. This was even more obviously called out in the FFS rules (both editions), where the player-designers actually had access to the formulae used.
Sigtrygg
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Re: Nuclear Missiles and Cumulative radiation effects

Postby Sigtrygg » Wed Nov 24, 2021 9:51 am

No, it didn't.
The hull and hull armour took no internal displacement tonnage from the ship in MT, it was one of the most pointed out silly design choices of the MT ship construction rules. It did increase the weight of the ship, but did not affect the available displacement tonnage for internal components.
Condottiere
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Re: Nuclear Missiles and Cumulative radiation effects

Postby Condottiere » Wed Nov 24, 2021 12:51 pm

In terms of actual protection, you probably need a minimum density/thickness for the hull, which in theory would decline percentagewise as the spacecraft would become larger.

However, there's still the issue of structural integrity, which would sort of stabilize percentage.

Much of how I like speculating of stretching a fuel bladder over a steel skeleton like a skin or condom to create volume, basically fourteen hundred cubic metres, or part thereof, I don't expect much protection from it.

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