Re: "Conventional" missiles for T:TNE

  First I'll list my assumptions about the missiles. There is a big risk
this will be obsolete when Technical Architecture and Brilliant Lances comes
out, but I need this stuff now for my own campaign (starting Saturday, provided
I finish a c program that converts old sectors according to Hard Times and
'collapse effects' by then) so I'll use the following until it is superceeded.

  Data given in TTNE: Normal missiles weigh 7 tons, communicate via a lasercom,
have 10-12 Gturns of acceleration, and use command guidance.

  Extrapolated data: They have a volume of 7m3.

  Assumptions: Normal xray missiles consist of a 150kg warhead(1), 100kg of
electronics, actuators and guidance (aka communicator), and all the rest is
a big engine. Their laser tubes are arranged to spread many beams to cover a
large area (like the shrapnel from a claymore) and on average 3.5 beams will
impact a 100m2 target(2) on normal range.

  (1) Fractional yield nukes shouldn't weigh much, probably around 20kg, but
the laser tubes takes up the rest.

  (2) This is the profile area of a 50t spherical ship. I use it as baseline
since class VS (10-99t) is used as baseline with regards to hit difficulties.

> I was thinking about, but didn't want to post before I have
> finished reading T:TNE, the following game mechanic: achieving a direct
> impact hit would be 2 levels of difficulty harder, and achieving a
> proximity hit would be 1 level of difficulty harder than the equivalent
> detonation laser targetting task.

  I think we should divide it into four types instead of three.

1 'Shrapnel' missiles with speed of light 'shrapnel' effective at long range.
  This is the nuke/laser missile given in the book.
  Standard difficulty.

2 'Shrapnel' missiles with slow 'shrapnel' effective at long range or spead
  of light shrapnel effective at short range.
  Cannister missile and nuke missile.
  One level harder.

3 'Shrapnel' missiles with slow 'shrapnel' effective at short range only.
  SFF missile.
  Two levels harder.

4 'Impact only' missiles.
  HE and HEAP.
  Three levels harder.

  (Short range is a km or two, long range is within the same range band. Slow
is everything slower than light. Shrapnel too weak to damage a ship (like from
a normal explosion) is ignored)

  I assume that types 3 and 4 include some kind of end phase autonomous
guidance (and a proximity fuse for type 3). Apart from this I agree with your
rules on final burn fuel.

  The reason for these increased difficulties is that HE and HEAP missiles
otherwise become more effecive than nuke/laser missiles:
  They have lesser penetration but inflicts *huge* amounts of damage.

> Active: Uses an active radar, ladar, or EMS sensor onboard the missile
> Semi-Active: Uses an active radar, ladar, or EMS sensor onboard the
> Passive: Uses a passive sensor (EMS, Neutrino, Densitometer, IR, etc) to
> Anti-Radiation: Uses a passive sensor designed to detect specific

  Isn't these types covered by the rules on SIM and FIM? Adding different types
is good, but I don't think it is necessary on this level. It can attached
as an optional rule to the FIM and SIM rules, but I don't think we should
include it so that it becomes necessary in order to use other missiles than
nuke/laser. We should keep it separate.

  BTW: Having some professional experience with missiles, IMHO the best
guidance model is the Track Via Missile guidance. It is basically a
combination of the best features of FIM and SIM.

  The missile has sensors of it's own and a guidance computer (as a FIM) but
it has also a communication link to the firing vessel (as a SIM or command
guided).
  The link enables the missile to use the much more powerful computer 'on the
ground' (ie on the firing ship in our case)' while the onboard guidance takes
over if the link is broken. The dual viewpoints (sensors on the firing ship
and in the missile) makes it more discriminating versus countermeasures.

  In traveller terms, I'd describe it as a FIM that uses the best of gunners
skill and onboard skill as long as it is in communication with the firing
ship during the final round. Normal restrictions on number of simultaneously
controlled missiles apply during this round.
  An additional trick that is possible with TVM missiles is the 'accumulated
wave attack'. Missiles are fired during several rounds and given (one at the
time) orders such that they will all arrive at the target simultaneously,
overwhelming its defences.

> Say, 1h everywhere, and 1H on the sides facing the explosion?  In
> general, your ideas sound about right to me, too.

  The soft xrays are totally absorbed by air 'within a few feet' from the bomb,
so I think all of them should stick in the hull on the side facing the
explosion. But the shock could travel on through the hull and affect all areas
to a lesser degree.

> > The cannister round replaces the nuke/laser warhead with a lot of heavy metal
> > spheres and a bursting charge. At the range where a nuke/laser missile would
> > detonate it spreads the spheres in a cloud which hit the target at high speed.
>
> I'm not sure, but I've always assumed that the detonation laser's range
> is tens of thousands of kilometers as a minimum.  At those ranges, the
> shperes would be spread too far apart to do much damage.

  I made some calculation on a missile that will spread 15000 1cm tungsten
spheres (10g each, total warhead weight 150kg).

  To achieve 3.5 hits against a 100m3 target, there has to be one sphere per
30m3. The radius of the cloud at impact will thus be 400m. To achieve a spread
of 400m at a closing velocity of 1 to 30 (60,000km/h to 1,800,000km/h) and
a range of 30,000 km (one range band) requires a radial velocity of 0.2m/s to
6m/s.
  So I persist that the 'detonation' range of the cannister round can be the
same as for the xray missile:) (Although I think a variable rate gas generator
might be more appropriate than a charge, since the rate of dispersion has to
vary with the closing velocity).

>>The SFF round uses an explosive warhead that generate the 'cloud of buckshot'
>>from self forging fragments (a relative of the shape charge, used in the
>>experimental SADARM round).
>
> Again, from detonation laser ranges, this will be ineffective.

  Yup, you need to be within a kilometer or two.

> From an "Impact" hit, all of these fragments
> would go into one or two hit locations, with pretty severe results.

  Perhaps too severe for game balance. The effect of one 10mm tungsten sphere
at 16km/second (closure velocity of 1) is 2-30 if I write it in the same
form as the laser damage. Imagine a 7 ton missile...

  I'll post a message with tenative designs for HE, HEAT, Cannister, SFF and
LGB missiles as soon as I've typed them in.

> [email removed]

- -bertil-
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