From: rwallace@unix1.tcd.ie (russell wallace)
Newsgroups: rec.arts.sf.science
Subject: Re: Wrecking an O'Neill (Was: Re: Wrecking a Planet)
Date: 11 Jan 93 15:09:34 GMT
Organization: Trinity College, Dublin

In <8fI5Ry200gpI89QF4N@andrew.cmu.edu> ap1i+@andrew.cmu.edu (Andrew C. Plotkin) writes:

>Excerpts from netnews.rec.arts.sf.science: 10-Jan-93 Re: Wrecking an
>O'Neill (Wa.. russell wallace@unix1.tc (2416)

>>  Remember, the
>> windows would have to be made shatterproof in case of a meteor impact,
>even if they hadn't been designed with missile attack in mind.

>But in space, there is no maximum impact velocity that you can design
>around. You can always throw rocks faster, at the cost of some more
>energy. (Steel-jacketed rocks.) Fast enough rocks make "shatterproof
>plastic" a joke.

By "shatterproof" I don't mean indestructible, I only mean that an
impact would make a hole, over which one can slap a patch, as opposed to
the entire window disintegrating as an earlier poster seemed to think
would happen.


>> But even if the windows did shatter, it would be an expensive mess, but
>> not fatal. Remember, to kill the population of a habitat, it is not
>> sufficient to just put the habitat in vacuum. You must totally
>> disintegrate it. 

>Ok, I can't kill off the population; all I can do is kill off all the
>crops, waste a habitat-worth of air, and force the population to do
>nothing but repair work for a while. And it costs me (forgive the
>repetition) rocks and energy, both of which are cheap; so I can do it
>again whenever I want. I think the habitat rapidly becomes not worth
>living in.

Just how do you propose to hit the habitat with rocks in the first
place? If you throw them from the asteroid belt, the habitat even at
very low acceleration will have dodged by then. So you have to throw
them from relatively nearby. That means you need to build at least one
huge battleship with a rail gun capable of accelerating rocks to very
high speeds, and capable of carrying significant quantities of rock to
throw, and enough power output to throw them. Oh yes, just rock won't
do, you need metal, presumably mined from a nickel-iron asteroid. Now,
battleships definitely are not cheap. Furthermore, the habitat will be
firing back at your battleship. The habitat, being bigger, can mount
more firepower. Being bigger it can also absorb more damage. So maybe
you inflict enough damage on the habitat to make for expensive repair
work. Meanwhile the habitat has a very good chance of destroying or
badly damaging your expensive battleship. I think the attack rapidly
becomes not worth keeping up. (Contrast this to an attack on a planet;
because you can hit a planet from almost any distance, you really can
get away with just throwing rocks from the asteroid belt.)

>>  That's the whole problem: you need smart missiles, which are
>> much more expensive than the bombs and decoys that suffice to attack a
>> planet; therefore you can have fewer of them; therefore the defensive
>> armament will destroy the relatively few missiles before they impact,
>> given that long-range armament is relatively cheap for a habitat to
>> build.

>Long-range armament is cheap for their enemies to build, too. I still
>don't see how any defense system can cope with an *unbounded* number of
>cheap stupid projectiles.

They will need to either be expensive, smart projectiles, or else be
fired by an expensive, smart battleship (see above). Of course a
sufficiently massive attack will swamp the habitat's defenses, but it
will be an expensive proposition, much more so than attacking a planet.

--
"To summarize the summary of the summary: people are a problem"
Russell Wallace, Trinity College, Dublin
rwallace@unix1.tcd.ie