Nuclear Missiles and Cumulative radiation effects

[PsiTraveller]

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]

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.

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]

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]

Speaking cumulative radiation effects, isn't that an issue with being outside the protective shield of the Terran atmosphere in general?

 

[NOLATrav]

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]

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

As in implying paper thin.

 

[NOLATrav]

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]

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]

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]

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.

 

[Alqualonde]

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.

You are right for MT.
In MT, armor (and structure) didn't take any internal space, with a minimum of 40AV for space-going ships (had to refresh my memory).
In TNE & T4 (with Fire Fusion & Steel rules), both armor & internal bracing took internal space (and a lot of weight). You needed at least 10AV per G. The armor value was calculated using the thickness with a factor depending on material (3AV per cm for Titanium Steel), not by volume like Mongoose Traveller (2.5% of volume per armour point for Titanium Steel). A large ship could devote a lesser portion of its volume and have the same (or better) protection than a small ship.

 

[Alqualonde]

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

As in implying paper thin.

MgT is glossing over a lot of things. Or at least consider them included with other components.
You don't need to devote space for internal bracing, for life support, for air locks (unless you want more than usual), and so on. It's part of your basic hull.
So I guess AV0 is included with the other components free of charge but is not paper thin (maybe an inch or two). Just enough to protect gainst micrometeorits and radiations, not enough for combat.
I'm not going to complain, it keeps the rules simpler than in FF&S.

 

[Condottiere]

Ye default airlock is two tonnes.

If you get a freebie airlock for every hundred tonnes, that's two percent of the hull to account for.

Now a plain old hatch, which would be part of the outer hull, could be squeezed in.

Life support is a very vague area that's difficult to grasp, or make sense of, in Traveller.

 

[Alqualonde]

From what I read in the Core Rulebook, ships have at least 1 airlock per 500dT.
In High Guard, in the options, the entry for airlock mention 'additional' airlocks.
Both on the Core & High Guard, the maps of the ships (at least for some of them) indicates airlocks but none are 'paid' for in the design sheet.
For exemple : The Far trader seems to have two of them on the maps but none on the design sheet.
I always guessed that there were a few by default 'for free' and if you wanted more (for exemple the cargo airlocks of the Empress Marava) you needed to pay for them. But I might be wrong for this.
Is there any clarification in the High Guard revised book?

 

[AndrewW]

From what I read in the Core Rulebook, ships have at least 1 airlock per 500dT.

That should be per 100dt.

 

[phavoc]

Armor of zero is possible with a minimal set of internal reinforcement. You have to have a minimum of internal structure to build the ship (i.e. it's skeleton). So I'd just handwave that into the normal construction. And the materials of the hull are the thing that magically eliminates the space debris issue/micrometeroids (personally I'd just explain it away as some sort of low-strength magnetic field that can divert small objects, but not larger ones (i.e. weapons). Sure, it has a massive hole in how it works, but it sidesteps the issue. So the hull IS pretty weak and thin, as far as starships go.

Armor, on the other hand, has to be able to stand up to kinetic energy transfer from explosions and direct hits. Waving aside the sheer amount of energy one might encounter, that energy has to go somewhere, and without internal structure the strongest slabs of armor on the outside have to transfer the energy somewhere, thus the underlying structure channels it safely away to dissipate it within the frame of the ship. That's how warship armor against shells worked - and why armor had more mass than just the outside sheeting - not to mention the armor itself.

I try to keep too many hand-waves out of the game. Here and there you've got to do some just to keep it at the game level. But unless you want to get up into space opera, you need some guidelines into explanations of how things are supposed to work.

 

[Condottiere]

You could say that structural integrity could be one percent, modified by material and hull configuration.