[Ground-station] Need some nuclear science help

[Jordan Trewitt]

I've been talking back and forth between other members and between other
guys on twitter about this too. Another material it looks like wasn't
mentioned is high density polyethylene (HDPE), which absorbs just like the
denser metals, but does not produce as much secondary backscatter. It is
also a whole 2.5 times less dense that aluminum if we wanted to look at the
weight factor.  I've been trying to read up between survey for radiation on
the moon and mars (
http://www.marsjournal.org/contents/2006/0004/files/rapp_mars_2006_0004.pdf),
or another survey that looks at aluminum, HDPE and Tantalum shielding (
http://www.imedpub.com/articles/shielding-protection-of-electronic-circuits-against-radiation-effects-of-spacehigh-energy-particles.pdf).
If we need to make the HDPE work as EMI shielding too, we can always add a
copper layer to it with copper spray paint like Michelle's 3D printed
antennas (as long as we flame treat the HDPE first).

I'll see what NASA has to say in a few weeks at the EPP electronics
workshop in a few weeks. Meanwhile, my boss (Karsten) has a pretty good
video about radiation on the moon with EEVBlog: https://youtu.be/7JwNmdV2QPs

-Jordan
KF5COQ

On Sat, Jun 2, 2018 at 12:16 PM Bruce Perens via Ground-Station
<ground-station at lists.openresearch.institute> wrote:

> We've recently heard proposals and seen some research regarding the use of
> radiation shielding to make it possible to use consumer or industrial grade
> parts rather than rad-hard ones. A cubesat called ShieldSat 1 flew to test
> some of this. My mostly-innumerate grasp of atomic science tells me that
> this can only go so far, and that when high-energy particles hit shielding,
> you get a particle shower that is sometimes more harmful than the original
> particle. But I don't have numbers.
>
> The proposal is to use the outer layer of structural aluminum, and an
> inner laminate of tantalum, titanium, and other dense materials with
> different atomic numbers from each other. Using titanium directly as the
> structural material, rather than aluminum, is possible; but it takes a more
> sophisticated (and expensive) laser cutter, and it has to be heated to be
> bent without cracking.
>
> What I'd like to hear would be numbers for reasonable thicknesses of these
> materials, and the degree to which they can, for example, make a
> van-Allen-crossing orbit look like LEO.
>
>     Thanks
>
>     Bruce
> --
> Bruce Perens K6BP - CEO, Legal Engineering
> Standards committee chair, license review committee member, co-founder,
> Open Source Initiative
> President, Open Research Institute; Board Member, Fashion Freedom
> Initiative.
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