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Re: What to do IF we regain control of AO-40

on 12/19/00 7:08 AM, sco@sco-inc.com at sco@sco-inc.com wrote:

> Ok your logic is good if the above is correct. What we don't know are the
> facts. We do know from what has been released that the valve did NOT work
> properly. Hence if it has failed even once (already) in flight that the
> odds are greater that it will not work properly the next time. A sticking
> valve in an engine usually does not fix itself ... does it? Now if the
> problem was associated with a small bur in the valve, the action of opening
> and closing it might have smoothed that down. Lets hope for the best.

You are also missing another important fact here.  Everyone assumes the burn
lasted longer than anticipated because of that valve issue.  We do know the
valve didn't work during the first burn attempt.  Beyond that, we've not
been given information about what happened with it on the second.  As far as
I know (and I would need to read up on the propulsion system operation to be
sure - perhaps we all should), the helium valves in question, are closed
once the pressurization routine is complete.  AFAIK, the valve doesn't stay
open for the duration of the burn and then close.

So you are making an assumption that the burn lasted longer because of the
"sticky" valve.  I don't know if that assumption is valid or not.  That is
part of what the control crew was analyzing.



Jon Ogden
NA9D (ex: KE9NA)



"A life lived in fear is a life half lived."

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