From: m23364@mwunix (James Meritt)
Subject: Wreaking a habitat (was Re: Wrecking a Planet 
Organization: MITRE Corporation, McLean VA
Date: Fri, 8 Jan 1993 14:48:35 GMT

In article <rwallace.726452375@unix1.tcd.ie> rwallace@unix1.tcd.ie (russell wallace) writes:
}In <1993Jan7.173125.20305@linus.mitre.org> m23364@mwunix (James Meritt) writes:
}>In article <rwallace.726348286@unix1.tcd.ie> rwallace@unix1.tcd.ie (russell wallace) writes:
}>}Sure, a 0.5-gigaton bomb (incidentally I got my calculations slightly
}>}wrong about the weight/yield ratio of bombs in my original message - a
}>}0.5-gigaton device will weigh about 10 tons) will probably totally
}>}destroy a space habitat if it gets a direct hit. (It will have to get a
}>}*direct* hit on a relatively small target, as opposed to being abl to do
}>}damage exploding anywhere in a planetary biosphere.) Even then, there
}>}will probably be survivors in sealed compartments who can be rescued
}>}later. But a population of say 10 billion will be scattered over *many*
}>}space habitats rather than all on a single planet, so even if many hits
}>}are scored, a lot of the population will still be safe.
}
}>Why bother with total destruction?  Have you considered the results of a
}>number of 5 inch holes drilled through it by very fast gravel?
}
}As I explained in another article, a piece of gravel is not at all going
}to drill a hole in a 1 billion ton O'Neill habitat.

Why on earth would you use one piece of gravel?  Send a gigaton or so of
rock towards it at a few percent of the speed of light.  I don't think
that your "measures" would do much good against a few million foot-wide
holes randomly scattered completely through the habitat...

}Plus, your attack carrier will have to get reasonably close to throw the
}gravel. 

Wrong.  The Oort belt, to pick a demonstratable rock-throwing region, is
not close.

}>}Most importantly however, is that a space habitat can move. Not with
}>}great agility, to be sure, but it means that a guided, powered missile
}>}is needed, not simply throwing bombs on a precalculated ballistic
}>}trajectory. 
}>Unless you are advocating near continuous random changes in acceleration,
}>it fits in much the same category as "planet" - except that the attack
}>could come from any location in the universe, as opposed to less than
}>half for a "moonbase".  There is something reassuring about being able to
}>have your back against a few thousand miles of protective rock...
}
}Presumably the attackers of a planet will have the wit to time their
}attack to hit the right side of the planet.  

That's nice.  So you can cut the time in half, too...  An attack against a
space platform could come at any time.

No comment on the problems associated with random sporatic acceleration?

}>}Also a bomb to hit a habitat
}>}will have to come within range of the habitat's own defensive armament,
}
}>So?  Tough to stop a rock...
}
}The habitat's defensive armament (which can be of almost any desired
}size and power output) can simply vaporize the rock a long way away.

Unfortunately, your saying so doesn't make it so.  If you have the
power available to vaporize a planet, the "defense" question is irrelevant.
A planetside base could have more available, through the same magic you
are involking.

}>}which can be of almost any desired size and power output, with the
}>}habitat's full power generating capacity available, and almost unlimited
}>}heat sink capacity, and the population on hand to maintain it. As
}
}>heat sink, yes.  But terribly vulnerable radiators.  So to zap it, dump silver
}>paint so that it coats the radiator.  And as for the "full power
}>generating capacity", if it is environmental, you couldn't accelerate
}>(read "move") and it could be closed down with black paint.  And if it
}>is internal, so could the planetary base.  
}
}Who mentioned radiators? The heat sink for a fusion gun or whatever
}could simply be the habitat's water reservoir. I think a 10,000-ton
}water storage takn could soak up quite a lot of heat (with bleeder
}valves in case the water got too hot).

Wrong.  If your "beam" is enough to vaporize a few megatons of rock,
with less than 1% of the beam even hitting the particles, you would
boil your water away long before it worked.  If you happen to have an
ocean available, or a river (read: planet) this might be a viable argument.
As is, nope.

Hmmm.  Thought - not only would you have to vaporize the rock, you would have 
to divert the the vapor (photonic pressure).  Otherwise you would just wind
up encasing the habitat in vapor-deposited material or STILL destroying
it with the energy transferred - and again wiping it out.  Getting hit with 
a cloud at those velocities would not be a terrific improvement...

}>}opposed to trying to defend a planet; the defences have to be in orbit,
}>}which means they're separated from the population and industrial plants
}>}which are on the ground.
}
}>Only if you are trying to defend the planet, and not just the "special"
}>site.  Most folks I know really wouldn't care if a few cubic miles of the moon
}>get peppered by gravel.  There is a LOT of turf that would count as a "miss".
}
}If an amount of nuclear explosives equivalent to a Dinosaur Killer hit
}the Earth, that would cause a lot of inconvenience to everyone. Plus
}that megatonnage aimed at say Europe would kill quite a lot of people.
}Even not aimed at specific targets.

And if it hit your habitat it would be vaporized.

Newsgroups: rec.arts.sf.science