Active Sheilding

I would have to do the math, but my gut feeling is that heat
dissipiation for an active shield will be the big problem. I can see
you converting the mass of a passive sheild into the mass of a
radiator to get rid of the extra heat created by the active shielding.

This may not be the case for small space ships. But I think even a
standford torus would be too big for active sheilding.

Bill

--- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
wrote:
> Bill,
>
> Yes, there are details that need to be worked out. Lets try a
thought experiment. Imagine a dumbell shaped space station with a huge
Van De Graff generator separating charges with one end + and the other
-. The - end could be sacrificed or perhaps it will contain the
nuclear reactor or political prisoners :-) while everyone else is safe
in the + end.
> If you like this concept, then replace the - end with an electron
gun that shoots electrons a long way away past the + charge. Perhaps
this gun is located at the end of a tether that also provides some
electrical thrust? Think about it.
>
> Tom
> From: bill t
> To: spacesettlers@egroups.com
> Sent: Tuesday, December 19, 2000 5:17 PM
> Subject: [spacesettlers] Active Sheilding
>
> The main problem with Active Shielding is the polarity of the
field.
> Since the radiation leaving the sun is positive a positive field
will
> repel the particles, but at the same time it will accelerate every
> electron in the vincinity of the habitat towards it. The resulting
> shower on the hull of the habitat will produce enough X-Rays to
kill
> anyone inside.
>
> You can arrange a magnetic field to deflect the electrons, but I'm
> wondering what the weight of the material, and the power
utilization
> is. All the power is heat that has to be radiated away. This means
> more radiators.
>
> How much real savings in weight is there, remembering that the
passive
> sheild will be waste material from industrial processes in space,
and
> the active sheilding material will probably be sent up from earth.
>
> Just a Thought,
>
> Bill
>
> --- In spacesettlers@egroups.com, "Combs, Mike"
> wrote:
> > From: Tom Tucker (Olympia) [mailto:tntucker@c...]
> >
> >
> > From: Dr. Omni
> >
> > It seems that youre a proponent of Active Shielding - the use
of
> magnetic
> > and electric fields to protect your habitat. What are the
> disadvantages that
> > you see with Passive Shielding - simply covering your habitat
with a
> layer
> > of rock (or ice, depending on your location in the Solar System)
a
> few
> > meters thick?
> >
> >
> > Tom - Primarily mass, although inertia will be important.
> >
> >
> > To me, this would be more of an issue for a travelling structure
> than a
> > stationary one.
> >
> >
> > However, I believe that the lowest mass, and hence, largest
volume
> for
> > equal costs, can be achieved using active shielding.
> >
> >
> > If the shielding is made up of slag left over from your ore
refining
> > operation, I don't see it adding a lot to the costs, at least
not
> from a
> > material standpoint. I don't think the construction costs would
be
> as high
> > as for the pressure shell, as I think the construction
requirements
> would
> > not be quite as precise as what's needed for a pressure shell.
> >
> >
> > It would be much better to just turn-up the voltage a bit when
a
> solar
> > flare is due rather than hiding in a shelter IMO.
> >
> >
> > I think the advantage of the 6' thick shield is that you can
just go
> about
> > your buisiness normally during flares.
> >
> >
> > A 4 meter tube/elevator becomes a 12 meter dia tube if shielding
is
> added...
> >
> >
> > I'd question if shielding was even needed for an elevator tube.
The
> 4-6'
> > shielding requirement is for what's safe to live in for the
rest of
> your
> > life. Since one would only spend a short amount of time in the
> elevator
> > tube, shielding requirements there would probably be somewhat
> relaxed.
> > Given the nature of primaries/secondaries, no shielding at all
may