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Sticky valves [was: What to do IF...]

sco@sco-inc.com wrote:

> NO, your logic is flawed. If the ground controllers had to make 10 attempts
> to open the valve when one (1) attempt would be the "norm" ... then the
> failure rate is 9/10 or 90 percent. If it had opened properly on the 1st
> attempt they would not have needed to make 9 more attempts to open it.

Hmm. Don't know about you, but when I deal with an electromechanical device that
seems to be sticking, and I want to maximize the chance it will work when called
upon, I tend to cycle it a bunch to "exercise" it and try to reduce friction by
working in the bearing surfaces. The repeated operating cycles aren't a symptom
of repeated failures...unless the valve was commanded open but did not open.

Lubrication and friction in space is a *very* tricky problem, given the vacuum
and extremes of temperature, and very expensive and difficult to simulate on the

 73 de Maggie KB3DXS

     / __     _)      Margaret Stephanie Leber  /"The art of progress   / 
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   /   / | / |  _   _   _    `  _ AOPA 925383 / order amid change and /
  / ) /  |/  |_(_(_(_/_(_/__(__(/_ARRL 39280 / change amid order."   /
 / (_/   '        .-/ .-/       AMSAT 32844 /___ --A.N.Whitehead ___/  
/_______KB3DXS___(_/_(_/______ ICQ 7161096 / <maggie@voicenet.com> /
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