Vulnerability of Space Settlements to Attacks

From: "Brett Sargeant"
To:
Sent: Friday, January 25, 2002 8:35 AM
Subject: Re: [spacesettlers] Vulnerability of Space Settlements to Attacks

[snikt]
> Build the new one in line with the spin axis of the older one, a short
> distance away, spin it up, using small thrust along the axis move it
> close to the other one, say 10 m for example then put in connecting
> access tunnels. Don't see that it would be that clumsy, is just a
> docking procedure writ large. Should be easy to match spin, and as long
> as you keep the joining velocity tiny, then there shouldn't be any
> trouble with moving them closer. If it is hard to put in the access
> tunnels after spin up, then put them inplace before spinning up then you
> only have to seal the join when they meet.
>

Yes, it would be a docking procedure writ *too* large, and that's the
problem. Imagine someone trying to make soft contact between two
building-sized structures - but with way more inertia due to shielding.
AFAIK, no "docking procedure" that large has ever been tried, and therefore
I tend to be conservative and refuse this alternative in favor of disjoint
habitats. Of course one day something like that will be tried and maybe it
will even become a standard procedure. Until then...

However, even though that works, you would still have a structure that can
grow only linearly and in a planned way - while an Earth-based city can grow
in two (and, in a limited way, even three) dimensions and with no planning.

[snikt]
> Why 2D ? why not 3D, space them correctly and you won't block the
sunlight.
>

Any 3D lattice that does not block sunlight has to have a 2D projection
where its elements do not overlap. So, why not construct a 2D matrix from
the beginning and thus avoid extra consumption of materials?

Of course, if you are considering *really* big matrices - megameters in
diameter - then perhaps you would have to consider tidal effects, solar wind
pressure and other forces that may favor a 3D structure. That would also be
a plus for avoiding traffic jam between the habitats. But for
metropolis-sized matrices I think that a simple 2D grid would suffice.

[snikt]
> Two problems with small habitats ( I am guessing you are meaning for one
> family unit an upwards ?)
>

Indeed.

> 1. You use the more material to provide the same volume of living
> space, And you would probably have to shield each one to the same sort
> of depth as an Island 1, which would make it cheaper to build an Island
> one than a cluster of space houses for the same population.
>

It depends if shielding is expensive. If you're building your matrix around
an asteroid, for instance, shielding will be very cheap, I think. In
cislunar space, though, building an Island One would indeed be cheaper than
building smaller habitats to hold the same population - and, yet, smaller
habitats may still be preferred due to incremental growth capabilities of
such architecture.

> 2. Smaller spin radius, could lead to problems.
>

Not if you're using a dumbbell architecture.

> B
[snikt]

L