Re: [amsat-bb] What to do IF we regain control of AO-40

[sco@xxxxxxxxxxx]

>
> >> 1.) Just because the valve stuck once doesn't mean it will do so again.
> >
> > But if it failed the first time in flight I would assume the odds are great
> > that it is not dependable or predictable [no control ability] at best.
>
>That is just NOT true.  You don't know that!  After all the valves worked
>FINE in the tests in the integration lab and in Korou.  So it may or may not
>stick again.
> >

> From what I have read here ... the valve failed on the ground test and 
> was repaired by the manufacturer but not replaced. It then tested ok on 
> the following ground test(s?). But it failed in space the only time it 
> has been used. If we assume that there was one ground test and one use in 
> flight then the part has so far demonstrated a 50 percent failure rate 
> when used. Not encouraging. Logic would then suggest that it has a 50/50 
> chance of working the next time. But since it failed on the ground then 
> worked after repair and then failed again we might assume that it may 
> have a 66 percent failure rate?

I further assume that this part has been used in other spacecraft and that 
the manufacturer has data (or should have) on its performance in space (and 
how to do work-arrounds).

>W4SCO


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