FFS modifications
Re: How Nasty Nukes Are (Td#346)
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Date: Sun, 16 Jul 95 01:02:01 -0400
From: Derek Wildstar <wildstar@qrc.com>
Subject: Re: How Nasty Nukes Are (Td#346)
> Les wrote:
> I took a 1 MT weapon, which according to the sci.astro FAQ is 4.2*10^9 MJ,
> and assumed that all of that energy would be available in an attack.
> I calculated that flux in MJ/cm^2 at various ranges, and took that as the
> intensity in the formula for laser DV.
>
> Range (m) DV
> 1 457
> 10 45
> 50 9
> 100 4
While I agree with your general approach (spread 4.2*10^9MJ over spheres
of various sizes), I'm not sure it's reasonable to model it as a single
laser beam. IF you assume that the laser model is appropriate for a nuke
(and it may well be - the bulk of the energy emitted is as soft X-rays,
approximately equivalent to a TL-15 tunable laser), the penetration factor
should also be figured as well.
In addition, the nuclear explosion attackes the entire exposed surface
area of the ship - some provision for this should be made, because all
exposed weapons and equipment will be affected.
Here's some suggested rules to play with (enjoy!):
Nuclear Weapon Damage
Range 100MT Weapon ------- 1MT Weapon --------- 10KT Weapon --------
<m> Pen Area Pen Area Pen Area
0 1/259229-810092 33753H 1/25923-81009 3375H 1/2592-8101 338H
1 1/1462-4570 190H 1/146-457 19H 1/14-46 2H
2 1/731-2285 95H 1/73-229 10H 1/7-23 1H
5 1/293-914 38H 1/29-91 4H 1/3-9 1h
10 1/146-457 19H 1/14-46 2H 1-5 1h
25 1/59-183 8H 1/6-18 2h 1-2 --
50 1/29-91 4H 1/3-9 1h ---
100 1/14-46 2H 1-5 1h
250 1/6-18 2h 1-2 --
500 1/3-9 1h ---
1000 1-5 1h
more --- --
Rad Hit 10km 1km 100m
Damage Effects:
A nuclear explosion within the "Rad Hit" range of a spacecraft will
produce a radiation hit, resetting computers (just as if the ship were
hit with a particle beam weapon). Explosions beyond this range have
no effect on a spacecraft.
Ground Zero: Determine the hull surface location nearest the detonation
(use the hull surface locations diagram from T:TNE or BL), and the distance
from the hull of the ship to the nuclear device. This location is attacked
with the penetration and damage value listed in the table above, exactly as
if it were hit with a TL-15 laser. In addition, all systems which appear in
the Surface Hits damage tables for that location are damaged with the number
of hits indicated in the "Area" column. In some cases, there will be excess
damage (any "Area" hits above 5H are automatically excess damage); this is
resolved normally.
Primary Damage: All hull surface locations which share an edge with the one
nearest the detonation are also attacked. The penetration, damage, and area
damage effects depend on the relative length of the ship and the distance
to the nuclear explosion. If the overall length of the ship is smaller
than the range to the explosion, then the primary damage range is the
same as thr ground zero range; due to the angle of the hull to the radiation
of the explosion, use one half (but never less that 1-1 or 1h) of the
penetration, damage, and area damage values that were used at Ground Zero.
If the overall length of the ship is larger than the range to the explosion,
move down one row from the ground zero range on the chart; this is the
primary damage range. Use the penetration, damage, and area damage values
from the chart for this new range. Apply primary damage exactly like Ground
Zero damage (except that the range is larger, and therefore the damage is
less); note that this may affect systems which already recieved damage atground zero (this is allowed).
Secondary Damage: All hull surface locations which share an edge with
one of the primary damage locations are also attacked. The secondary
damage range depends on the primary damage range and the length of the
ship. If the overall length of the ship is smaller than the priary damage
range (determined above), then the secondary damage range is the same
as the primary damage range; due to the angle of the hull to the radiation
of the explosion, use one half (but never less than 1-1 or 1h) of the
penetration, damage, and area damage values that were used in the primary
damage. If the overall length of the ship is larger than the primary damage
range, move down one row from the primary damage range on the chart; this is
the secondary damage range. Use the penetration, damage, and area damage
values for this new range. Apply secondary damage exactly like Primary
Damage (except that the range is larger, and therefore the damage is less);
note that this may affect systems which already recieved damage at ground
zero or in the primary damage area (this is allowed).
Examples:
1) A 1MT weapon explodes about a shiplength (25 meters) astern of a
Broadsword-class mercenary cruiser. Ground Zero is location 20, and it
is attacked with 1/6-18, of which 13 points (2 minor hits) penetrates
the ship's hull armor. There are no systems exposed to a surface explosion
in this area, so no additional damage is done.
The Broadsword is longer (at 28 meters) than the distance to the explosion,
so the primary damage area (locations 16, 17, 18, and 19) is treated as
if it were 50 meters away. These locations are attacked at 1/3-9 (which
does not penetrate). However, the airlocks, cargo hatches, antennas, and
docking ports in these areas all recieve minor hits anyway.
The primary damage range, 50m, is larger than the length of the ship (28m),
so the secondary damage area (locations 10, 11, 12, 13, 14, and 15) recieves
half the damage that the primary area does. Unfortinately, 1/3-4 damage
doesn't penetrate anything. However the 1h (half of 1h, but never less
than 1h) surface damage now affects more systems: airlocks and antennas
in these areas, for a total of 6 more 1h results on each (and pretty
effectively destroying the antennas and airlocks on the aft hemisphere
of thie ship.
2) A 10KT contact nuclear mine detonates 1 meter (the length of it's contact
sensing elements) from the hull of Midu Agashaam-class Destroyer, in hull
location 7. 41 points of damage penetrate the hull, for 2 major hits. In
addition, the antenna in that location recieves an additional 2H. The ship
is much longer than a meter, so the adjacent primary damage area locations
(3, 9, 10, and 13) are attacked at 1/7-23, of whih 14 points of damage
penetrates, for 2 minor hits in each location, plus two major hits on both
the antenna in location 10, and the airlock in 13). The ship is also
longer than two meters, so the secondary damage area (locations 1, 2, 5, 6,
11, 12, 15, 16, and 16) are attacked with 1/3-9 (which doesn't penetrate),
however, antennas, airlocks, and EMM radiators in these areas recieve 1h
each time they appear in the damage table.
"Bruce Johnson" <JOHNSON@tonic.pharm.arizona.edu> writes:
> Of course, the radiation effects will be greater in a vaccum (all
> that energy's gotta go <somewhere>) so there will be a LOT of very
> high energy radiation in all directions, spread all across the
> spectrum.
Actually, no. Without an atmosphere around the blast, nearly all the
energy should come out as either high-speed neutron radiation or "soft"
X-rays. The bulk of the energy will be in the form of the latter.
In an atmosphere, these "soft" X-rays are absorbed by the surrounding
air, heating it to very high temperaturs (and thereby creating the
fireball and blast effects). The fireball re-radiates a considerable
amount of energy, spreading it over a broader range of lower frequencies.
These effects don't happen in space.
> So a shiny or white surface
> will be able reflect a lot of the energy back, and the armor should
> easily handle the rest, it had better...your average solar flare is
> going to put out energy on the order of a nuke going off nearby, and
> do it for days to a week at a time. I don't think that nukes put out
> the high energy particles like solar flares, it's mostly photons
> (very high energy photons, to be sure, but photons nonetheless).
Actually, no. At detonation, the majority of a nuclear weapon's energy
output is "soft" X-rays (yes, these are photons, folks). Just about
any type of matter absorbs this radiation efficently, and since FF&S
assumes that TL-15 tunable lasers would operate in these ranges, it's
a safe assumption that starship hull will be just as easily damaged
by nuclear-explosion-generated soft X-rays as it is by a laser weapon.
wildstar@quark.qrc.com
------------------------------------------------------------------------------
"A shining New Era is tiptoeing nearer ..."
"... and where do we feature?"
Date: Tue, 18 Jul 95 13:37:40 -0400
From: Derek Wildstar <wildstar@qrc.com>
Subject: Re: How Nasty Nukes Are (Td#350)
lhowie@dilbert.lrmi.com (Les Howie) asks:
> > (( useful tables omittedd ))
One more Nifty Thing. The values in the tables I gave previously can be
adjusted for different sized nukes. The general formula is:
Multiplier = sqrt(Desired Yield / Table Yield)
In other words, if you want values for a 20KT warhead, multiply the 10KT
penetration, damage value, and area hits by sqrt(20/10), or 1.4142.
Here's a table to help you out; instead of saying "* .333333",
I've given it as "/ 3", indicating division by three.
Yeild Table and Mult
2.5KT 10KT / 2
40KT 10KT * 2
90KT 10KT * 3
111KT 1MT / 3
250KT 1MT / 2
4MT 1MT * 2
9MT 1MT * 3
11MT 100MT / 3
25MT 100MT / 2
Round all fractions to the nearest (in other words .5 and above rounds up,
less than .5 rounds down). The only exceptions are that penetrations less
than 2 round down to one, and penetrations or damage values less than one
indicate no effect. Area hits work the same way as long as you are working
with major hits; less than 1 major hit (but at least a half of a major hit)
becoems two minor hits; less than half a major hit (or half of two minor
hits) becomes one minor hit.
> These are excellent rules, and I will use them. The only thing needed for
> space combat use now is a set of rules for getting a missile inside this
> sort of range.
I think I've posted rules for that before. :-) Check the back issues of
TML, or use the following quick summary:
To qualify for a "short range" attack, a missile must:
1) end it's flight in the same hex as it's target
2) have remaining maneuver G's to match the target's evasion G's
3) survive any point-defense fire
Roll a normal missile "to-hit" roll, with the following diff mods:
"Impact" = 3 levels harder
"Near" = 2 levels harder
"Far" = 1 level harder
MFDs can be used to offset those difficulty mods. Once a hit is acheived,
roll 1d6 on one of the following tables to determine the exact distance from
the explosion to the target vessel. Apply a -1 DM to this roll if the
target ship did not evade at all.
Impact Near Far
Die Distance Distance Distance
0 0 10 100
1 0 10 250
2 1 25 500
3 1 25 500
4 2 50 500
5 2 50 1000
6 5 100 2000
> question: how should armour protect against the "rad" hit?
Not at all; invest in radiation-hardened electronics and computers if you
want to survive radiation hits (ie: "fib" fiber-optic computers).
wildstar@quark.qrc.com
------------------------------------------------------------------------------
"A shining New Era is tiptoeing nearer ..."
"... and where do we feature?"