Re: Planetery Defense Batteries

On Tue, 2 Feb 1999, Tony Francis wrote:

> devans@uneb.edu wrote:
> 
> > Also, what is the 'down' angle to the horizon of an Earth-style
planet, say at
> > 100 feet above the surface, assuming a really tall PDB? Five mi?
Seven mi? Top
> > of Everest without other mountains to worry about? Top of Mons
Olympus? Near as
> > much as the 30 degrees required for going to 240?
> 
> Laying myself open to corrections by better mathematicians, the
following are what
> I reckon the total arcs of fire (horizon-to-horizon) would be for the
specified
> altitudes on an Earth sized planet :
> 
> Planetary Radius 6500km
> 
> Altitude (m)	  Arc		 Horizon (km)
> 
> 1000000	 239.85       3741.66
> 
> So, to get to four FT fire arcs we need to be 1000km above the
planet's surface

well, i can only think of one way to do that (other than a satellite in
LEO).

SPACE ELEVATOR!

a beanstalk extends from the surface to 40 000 km, and you can build
things part-way up, if it is built strongly enough. you could run
superconductors and ammo lifts up the elevator to supply it. it might be
rather neat, in fact.

since most people now consider that a beanstalk would be made from a
cluster of independent but interlinked fibres to minimise impact damage,
the firebase would have to be strung from them, much like a gondola is
from a balloon, with weapons muzzles poking out between the fibres. it
would look very odd, but it'd be cool.

Tom