[ExI] Why space tech isn't cutting edge

[Adrian Tymes]

On Sat, Nov 24, 2012 at 8:23 PM, spike <spike66 at att.net> wrote:
> ... On Behalf Of Adrian Tymes
> Subject: Re: [ExI] Why space tech isn't cutting edge
> On Sat, Nov 24, 2012 at 2:56 PM, spike <spike66 at att.net> wrote:
>>> ...  Of course with sufficiently thick shielding, you could physically
> stop the particle and everything it generates.
>
>>...How thick are we talking, approximately?
>
> Good question.  The atmosphere is equivalent to a little over half a meter
> of tungsten, so if that is sufficient, then a spherical shield would have a
> mass of about 16 tons.  What do we get?  Another day older and deeper in
> debt...

That might not be so bad for larger spaceships.  But then, I've
been looking at smaller rockets anyway.

>>...  Because if so, then you have to worry about the spall cone that is
> generated inside the chip itself - forget about any shielding, if the cosmic
> particle itself is not prevented from intersecting the chip...
>
> Keep in mind that cosmic rays come in all sizes.  So any shielding stops
> some particles, and some particles punch right through any shielding.  In
> the above example of using 1 atmosphere equivalent shielding, some particles
> can punch all the way through the atmosphere.  If you ever get to see a
> bubble chamber, there you see particles that penetrated the atmosphere and
> the ceiling of whatever building you are in.  Our electronics work anyway,
> so there aren't many of them.   But some do make it.

Hmm.  If our entire atmosphere is equal to a half meter of tungsten,
and that produces an acceptable error rate - might the error rate
still be acceptable with less shielding?  What's the thickness to
error rate relationship - would a quarter meter double the error rate,
less than double, or more than double?

>>...Also, is it possible to meaningfully alter the course of the cosmic
> particle - say, over the distance of 10 meters, deflect it by millimeters?
>
> Millimeters over 10 meters, I would sure think so.

Then, is it possible to absolutely protect a cubic millimeter in the
center of a 20+ meter diameter ship?

And then is it possible to absolutely protect multiple such cubic
millimeters, by shunting the cosmic particles into the spaces
between said millimeters?

And does the diversion mechanism need to be enclosed within
the spaceship, or can it be an electromagnetic field that is mostly
or entirely projected outside a (say) 1 to 2 meter diameter rocket,
to protect CPU cores at its center?

> Adrian, you are making me THINK
> here.

You are quite welcome.  :)

>>>... I hope you come up with a solution to that cosmic ray problem.  We are
> cheering wildly for you Adrian.
>
>>...Yeah, well, only if you help.  :P
>
> Oy, I could fill a library with what I don't know.  Actually I couldn't:  I
> wouldn't know what to put in it.

I don't mean just what you don't know, but also what you do - and
more importantly, what you know that you didn't previously think was
relevant.  ;)