From: damm@diku.dk (Kristian Damm Jensen)
Newsgroups: rec.arts.sf.science
Subject: Re: Wrecking space colonies
Date: 12 Jan 93 10:53:45 GMT
Organization: Department of Computer Science, U of Copenhagen

This discussion has come to a point where no real progress are made.
(Except Thomas Koenig article, in wich he outlines 8 ways to avoid
damage.)  It is not interesting to device new ways to destroy a planet
or a spacehabitat. Of course it can be done.  Remember, given enough
power you can destroy any attack/defence. The question is wich one is
easier to defend.


Let's review som of the point made in this discussion.

There are essentially three different kinds of living spaces you might
want to try to defend: (1) a planet with an atmosphere (Earth), (2) a
planet without an atmosphere (Moon), (3) a spacehabitat.

(1) You are in big trouble. Due to the atmosphere you can't have
defensive beams on the ground, you have to deploy them in space - far
from the industri and population, meaning great maintenance costs.
Furthermore a simple attack with nuclear bombs will be able
to destroy the biosphere, forcing you to live sheltered as on the
moon, but without the advantages the moon would normally give you.
Nuclear bombs are relatively cheap an can be thrown at the planet with
great accuracy from a geat distance. The attacker don't have to hit a
specific target, he only needs to hit the planet! Nuclear pollution
does the rest.

The only advantage left is that the atmosphere won't allow a "handfull
of gravel" to poke holes in you shelter.

(2) and (3) are quite similar. Neither of them can rely on the
environment to give them any advantages, and both have the problem of
(a) excess heat (b) protecting itself from the environment (c) ... But
they can have the defensive measures right beside the population and
industri for easy repair. Powering and so on will be the same. 

(2) can only be attacked from 1/2 the perimeter, but considering that
the existence of a horizon gives the attacker something to hide behind
I don't think this is much of an advantage. As russell wallace wrote:

>OK, let the defenders of the moon base have detectors that can pick up
>an incoming attack on the other side of a mountain, perhaps by
>distributing the detectors, or putting them in orbit. What good will
>that do them, when the attackers are on the other side of a mountain,
>which the defenders' guns cannot fire through? On the other hand, the
>attackers only have to detonate a big enough bomb on the other side of
>that mountain for the shock wave to wipe out the base. Space is lousy
>for transmitting shock waves, but solid ground is wonderful for the
>purpose.

Someone said that this means that a moonbase can only be attacked half
the time. Not quite true. Since you don't know the location of the
attacker (he might even be able to mount attacks from several
dirrections) you can't tell when an attack might hit you.

(3) can move. Not fast, but fast enough that a handfull of bombs or
gravel thrown at a great distance (maybe) can be dodged. This leaves
the attacker with to possibilities. Either use guided missiles (not
quite as cheap as bombs) or move closer in (enhance the risk of being
spotted and being hit be a counterattack). Note: the habitat can be
anywhere in the system, even orbiting Earth it can still dodge.

Considerations as to how big the pieces of gravel will have to be to
poke a hole in a spacehabitat (or make it through the atmosphere, then
poke a hole) remains to be seen on the net. I reserve my opinion till
then.


MY CONCLUSION: even though it is not easy to defend, I think that a
spacehabitat is a little easier to defend than a moonbase. 

Considering a planet with an atmosphere, how would you go on
destroying, when you have forced the population to take shelter?

-- 
Kristian Damm Jensen (damm@diku.dk)
"Life is like a sewer - what you get out of it depends on what you put into it"
- Tom Lehrer
Xref: sparky rec.arts.sf.science:3963 alt.folklore.science:4581