From: m23364@mwunix (James Meritt)
Subject: Re: Wrecking space colonies
Organization: MITRE Corporation, McLean VA
Date: Tue, 12 Jan 1993 14:31:09 GMT

In article <1993Jan12.105345.21569@odin.diku.dk> damm@diku.dk (Kristian Damm Jensen) writes:
}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.

Wrong.  On a planet there is a lot of hit-nokill space.  Look at the
earth from space.  A hit of only a few kilotons (one hit) randomly placed
over appox 80% of the surface might not even be noticed.  
}
}(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. 

A planetary-sized base cannot be attacked from at least one side.  There is
a LOT of shielding on the bottom of a moonbase.

}(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.

This has been a solved problem for decades.

}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.

A given attacker can only attack half the time against a base which
is 100% effectively shielded against half of the surface.

}(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.

Not "a handful". Tons.  thousands of tons.  Accelerate it first, then frag it.

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

I disagree, for the reasons given.

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

Considering that the populace of a habitat is ALWAYS taking shelter,
I do not believe that this is a suitable argument.

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