[amsat-bb] Re: Technical question regarding the long term performanceof nylon in space

Robert Bruninga bruninga at usna.edu
Wed Dec 10 16:31:33 PST 2008

> It has been suggested that the nylon 
> "fishing line" that is sometime used 
> on space craft to retain a deployable 
> item like an antenna or sensor will 
> decay quickly in space due to 
> radiation and out gassing...
> Does anyone have any data on this or 
> know if any research has been done?

Yes!  We tried to test this on PCSAT.  We had a 6" string across
one face pulled by a spring to a microswitch.  The idea is that
when the string broke, then the switch would close and we would
see a change in the telemetry.  It is the last "1" bit in the
PCSAT telemetry.

We even prepared a dozen strings for testing on the ground in
Arizona.  See a picture of the test set-up on
www.aprs.org/pcsat/springs.jpg. For the life of me, I cannot
find a picture of the string on the satellite, though I stumbled
across it just YESTERDAY for the first time in 7 years!

Anyway, in the 12 days sitting on the launch pad, apparently the
string broke before launch.  But on the photo above, is the
detail about when the other 9 strings broke.

The string we were using was just a few strands pulled from the
rather large polypropelene twine that you buy from Home depot.
The strings were pulled across a rather sharp edge on the test
stand shown.  Handling and vibration would also contribute to
failure of the string at that point.

We tried...


> thanks
> Graham
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