<html><head></head><body><div>On Mon, 2017-08-28 at 16:55 -0400, Phil Turmel wrote:</div><blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex"><pre>On 08/28/2017 01:50 PM, Jim Kinney wrote:
<blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex">
The (bs) EMP bags made me think (usually a good thing!) about circuit
design (a field I'm not good in).
For a spacecraft, the obvious choice for ground plane is the craft
framework itself. Relative to the typical power loads in the various
modules on ISS, the frame is a "near infinite supply or sink of
electrons".
But space weather is nasty. Solar flares are huge problems. How is a
system designed to withstand an EM flux greater than the typical power
throughput? On the ground, we use fat braided copper wires and deeply
buried rods. That's not an option on a satellite. Thick skin can
shield. What else?
</blockquote>
You don't shield everything. You shield the ICs with as small a shell
as possible, and every other circuit in the whole spacecraft is a
precision engineered tightly twisted pair w/ carefully balanced current
flows. Both power and signal. Plus optical isolation between any
devices grounded to different parts of the structure.
</pre></blockquote><div><br></div><div>My original grad school interest was the physics side of optronics/digital optics - making switching materials out of purely optical components.</div><blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex"><pre>_______________________________________________
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</pre></blockquote><div><span><pre><pre>-- <br></pre>James P. Kinney III
Every time you stop a school, you will have to build a jail. What you
gain at one end you lose at the other. It's like feeding a dog on his
own tail. It won't fatten the dog.
- Speech 11/23/1900 Mark Twain
http://heretothereideas.blogspot.com/
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