High-speed Spaceguns

Leonard Erickson writes :
Subject: (2670) How to kill a battleship...

> A *big* mass  driver  on  an  asteriod  hull.  It  fired  multi  kilogram
> projectiles  at  say  10  km/sec or better. They were aimed as a "time on
> target" barrage. Sure, it takes *months* for them to  arrive  on  target.
> So  what?  You  *cannot*  armor  against a several kilo projectile with a
> relative velocity in the tens of km/sec. And all a big ship gets  you  is
> the  chance  to  intercept more of these "rocks".If we assume high TLs in
> traveller, I bet we could boost  these  things  to  a  high  fraction  of
> lightspeed.  In  which  cause they are equivalent to a nuke! And they are
> *inherently* stealthed. Scratch any ship  whose  moves  you  can  predict
> sufficiently  far  in  advance.  True, this is *definitely * limited to a
> "Pearl Harbor" scenario, but they can  happen...  say  just  as  the  big
> naval manuevers get underway?

The  drawback  with  this method of attack might well be that space isn't
entirely a vaccum. Interplanetary dust and gasses will  tend  to  collide
with  the  projectiles,  and while this is no real problem at low speeds,
it gets worse as the projectile ( or spaceship ) gets faster.

At a high fraction of lightspeed, the projectile will have to be made  of
something  very  special  if  it  is  not  to  be  ripped  apart  by such
collisions, and it will certainly radiate *lots * of  energy  from  them.
As  for  a  defence  against  such  things,  once they have been detected
smashing their way through space, how about an old-fashioned  sandcaster?

The  impact  with  all  those  particles  will  the  projectile  no  good
whatsoever,   and  if  it  can  somehow  survive  those  impacts  at  0.1
lightspeed then it's  time  to  fall  back  on  repulsors  ,  lasers  and
throwing the kitchen sink at it :-)

Perhaps someone with more astronomical know-how could let us know what
you're likely to run into travelling through a crowded solar-system at
such speeds, and what the impacts will do ?

			Simon Anderson