From: johns@ssd.comm.mot.com (Mike Johns)
Subject: Re: Wrecking a Planet (Was: Re: Sci-Fantasy Weapons)
Organization: Motorola LMPS
Date: Mon, 11 Jan 1993 12:07:37 GMT
Keywords: nn


In article <rwallace.726568161@unix1.tcd.ie> rwallace@unix1.tcd.ie (russell wallace) writes:

>It could be made of steel or aluminium, though something like kevlar or
>synthetic diamond would probably be available at that stage, and be
>stronger weight for weight.

Diamond?  Strong yes but isn't it a bit brittle?  An attack that makes an
annoying leak in a steel habitat.  

>The outer shell would have to be many metres thick to withstand the
>tensile stresses and also to shield the colonists from cosmic and solar
>radiation, so I don't think a HE bomb is going to do any damage. Also
>you can provide sealed compartments for all the colonists to get into
>during a raid, and small leaks are easily fixed, so a few small holes
>wouldn't cause much of a problem.

>When figuring out how one might attack an O'Neill habitat, I'm assuming
>that the citizens have planned for the eventuality that they might be
>attacked, and have taken steps to defend themselves. Obviously if they
>have no weapons the thing is a foregone conclusion! The same applies to
>an attack on a planet, or any other act of war.

Hmmm, we are assuming that large numbers of people live in these things?
There was mention of enough of them to support a planetary population.
So we assume a large number of habitats made of plentiful materials designed
to be safe enough to convince people to spend their lives and raise their
families on them, but probably not built too far beyond these margins, because
the "spaceestate" developer who builds to DOD specs will find prospective
tenants unwilling to pay for $500 toilet seats.  Yes it does seem reasonable
to give such a habitat some sort of weapon, to keep away rocks that go bump
in the night if nothing else.  But really?  Spending delta-vee like drunken
sailors in defense against an attack that we don't even know about yet.  Given
how big you stress that this thing is, even small velocity changes won't be
cheap.  Since this is an age of atomic weapons building stronger than necessary
to keep out natural hazards may be a waste of time.

Given that we are building habitats and not government boondogles, I would
propose that we build them out of steel with a thick outer shell of mine
tailings for radiation shielding.  This has been the building material of
choice amongst the space station set because it is stuff we can easily lay
hands on without venturing into deep gravity wells.

So how big is our billion ton habitat?  How fast does it rotate, and how
strong does it have to be? A billion tons could describe a unbelievably
long length of PVC pipe but I doubt that that is what you had in mind.  I
admit to not knowing the numbers but I would haved guessed we are talking
about a meter or two of steel and another 7 or 8 of rock.  If this is the
case it can probably be sunk by a WWII naval vesel brought into orbit by
Japanese animation fans and manned by g.e.r.m s.

>
>Note however that a habitat is vastly cheaper to defend than the Earth.
>You can build fixed-mount weapons right next to your population and
>industry, rather than trying to maintain them in orbit. And the habitat
>will have lots of civilian spaceships which could easily be armed and
>used as interceptors; from the Earth's point of view, spaceships are
>much more expensive to operate, and much more of the total lift capacity
>must be used just getting into orbit.

The Earth does have one advantage.  Suppose someone does use the
nuclear weapon which for some reason we have decided not to use.  Well yes
blame me since I proposed that nukes were uneccessary.  The earth will not
split in half when hit directly or in proximity with a 1 megaton bomb.

Mike J -- johns@ssd.comm.mot.com

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