Re: Planetary defenses

Los spake thusly upon matters weighty: 

> Tom McCarthy wrote:
> > Railguns on the planet need way more power to overcome gravity, so
> > they
> > probably don't track well.
> >
> 
> True but a planet could again have infinately more power available to
it
> than whatever a hsip carries. In fact now that I think of it, scew the
> booster SML concept. Launch SMLS via railgun. (Small SMLs) It gets
them
> into orbit without a discernable signature,and then tey take over from
> there.

Try railguns powered by huge sources of energy such as geothermal or 
linked subterrainean fusion reactors. Enough power to overcome 
gravity easily and to still hurl big chunks of mass at high speed 
accurately (I think).  

> We talked about this a few weeks ago. The US is fielding an
operational
> fleet of seven 747-400 mounted ABM lasers. They've liked the
atmosphere
> thing in testing at least.  Power would be the main consideration.

Sure they aren't X-Ray lasers though?
 
> As far as fixed defenses, who needs them? We can have mobile defenses
> based loosely on the Soviet rail mounted ICBM launchers where they
have
> a several hundred square kilometer area to stick and move from. Shitty
> weather, good ECM, and electronic masking can make targetting from
orbit
> pretty damn hard.

Of course, weather works both ways. 
 
> And as for sitting around lobbing nukes into a planet. A nuke, a bomb
or
> a missile can be shot done given sophisticated tracking just like any
> thing else.

Sure, I just lob some ECM drones (a SFB concept) which project the 
image of ten missiles onto groundside tracking, a bunch of dummy 
missiles, and my nukes scattered between. But for every attack a 
counter..... 

> Now dropping a boulder big enough to wipe out 300 sq miles is a little
> tough to stop. Almost as tough as it would be to get the thing and
fling
> it into the planet with accuracy from a safe enough distance without
> jeapordizing the ship.

Difficult to do. But how about simply a few thousand pound (one 
volkswaggen worth a la New Jersey) chunk of metal (maybe with an 
ablative coating) launched in at some decent fraction of C. Bang! 
Nuclear bomb, comes in faster, hits just as hard. Way cheaper to 
field. Can be fired on ballistic trajectory from outside of defender 
weapons range. No guidance to fool. 

> Obviously so much of this is situation specific, but I have to believe
a
> planet, could have greater potential resources and staying power than
> the fleet sitting up in orbit.

Or not. Depends on lots of things. Atmosphere is a good defensive 
factor - makes space fighters function less well, slows ordinance, 
disipates beams. By en large, a planet only has to have enough force 
to deter attackers, not destroy. In theory, your fleet would be doing 
that.
  
> Hey you guys are all intelligent enough to sit around and come up with
> pat answers on bombing a planet into submisison but noone can think of
a
> way to defend it? I don't buy that. <grinning, ducking, running>

Actually, I think people can come up with point and counter for quite 
a while and (like the PA discussion and the FTL discussion and 
others) all depends on relative costs of technology and its 
efficiency for the task. So its all 'referee' or 'campaign designer' 
dependent in the end analysis. 

 I'm
> looking for solutions that don't involve space based defense. That's
> obvious. And essential. What about Close in defense? Think of a naval
> example. When a naval task force losses it's air cover it stilll has
> something to fall back upon to defend itself from missle and air
> strikes. Nothing is 100% of course.

Military installations would have short range, high power gatling 
laser point defences (powered from their power plants), counter 
missiles, high speed railguns, lots of concrete, dirt, ablative 
shielding, EW (backed by a LOT of power), etc. It might not be hard 
to nuke a city from orbit, but Nuking the Septagon(Hexagon, Dodecagon 
whatever) defence HQ might be 1) hard to do 2) a minor irritation to 
its occupants. It may be that ground assault is still needed (or a 
hell of a lot of will to spend ships and missiles and other 
ordinance) to root out fortified ground defences.  
/************************************************
Thomas Barclay		     
Voice: (613) 831-2018 x 4009
Fax: (613) 831-8255

 "C makes it easy to shoot yourself in the foot.  C++ makes
 it harder, but when you do, it blows away your whole leg."
 -Bjarne Stroustrup
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