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...

Bob, WB4APR

thanks

Graham G3VZV _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings:

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Hey Graham--

Make sure not to use the "UV resistant" monofiliment fishing line. If I remember correctly, we had a hard time finding non-UV proof fishing line in our local stores when we were trying different antenna tying methods for our CubeSats.

Later! -- Bryan Klofas, KF6ZEO

Graham Shirville wrote:

Hi all,

I think this is a new one!

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 destroying its structure.

This might mean that the usual "hot" knife type cutter system could be redundant if quick release is not a mission requirement.

Does anyone have any data on this or know if any research has been done?

thanks

Graham G3VZV _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb