Date: Wed, 11 Jun 1997 12:12:08 -0700 (PDT) From: Anthony Jackson Subject: Re: More Vehicle questions in space MA Lloyd writes: > Concussion drops to zero unless the explosive is in contact with the > target (OK, maybe you could assume a small range, 1 hex per 1000 lbs > of actual bomb weight perhaps). Fragmentation and flash damage don't > change, and radiation can be multiplied by the range multipliers for > x-ray lasers. Though V2E pretty seriously overestimates flash damage. By their rules, a megaton nuke on a clear day, at a range of ten miles, has a flash damage of roughly 180 pts (12d*2 billion * 0.2 / 18000^2), enough to punch through several inches of steel and turn a human into a gas cloud. This neither corresponds to statistics I have heard about nuclear weapons (which claim _much_ smaller flash-kill radius; typically a few miles) nor to physics. A megaton nuke has an actual energy of about 4e+15 joules; in atmosphere, a large portion of this energy will be absorbed (in space, it will all be flash). A sphere with a radius of 10 miles (16 km) has a surface area of roughly 3e+9 square meters; this gives an energy flux of 1.3e+6 joules/m^2. This is enough to vaporize roughly 0.5mm of water, or raise 5mm of water to boiling; this is enough to be unpleasant for unarmored flesh, but will have no detectable effect on any form of armor, and would probably be stopped just fine by medium to heavy clothes... For realistic flash damage: base flash damage is equal to 0.001 * (nuke damage) / r^2; this will penetrate armor as if impaling. _After_ applying armor, multiply damage done by surface area/5 (deal damage to every component). Assume a human as a surface area of 20, , natural DR of 0.25; clothing has DR 0.5 against this (reduce this for partial coverage). If there is any cover which would give detection penalties to ladar, for every point of cover either half damage or reduce damage by 10, whichever effect is _less_. Thus, a megatonne flash, at 10 miles, would do: 8.4e+10 * 0.001 / 8.1e+7 = 1; less 0.75 DR, multiplied by 4, 1 pt damage. In addition, nuclear weapons are quite likely to cause blindness; multiply damage (before DR or multiplying for area) by 10 and add 4. This is the penalty to HT rolls to avoid blindness. On a success by 5+ there is no effect; success by 0-4 gives -3 vision/DX for a minute, failure by 1-5 means blind for 10 seconds*failure, -3 vision for 2 minutes*failure. Failure by 6+ or a critical failure is treated as a crippling injury to the eye, failure by 10+ is permanent blindness. Visual sensors are subject to similar effects; assume that HT is equal to 16-scan/2 (yes, better sensors are _more_ vulnerable). Military sensors get an additional +5 against this, and will recover in a tenth the normal time unless actually blinded. Many sensors can also be run at reduced sensitivity; for every -1 scan, give +1 to HT rolls.