[amsat-bb] Re: The hard questions..

["Stacey E. Mills" <w4sm@xxxxxxxxxxxxx>]

>If it was known that the Aux batteries would be switched inline during a
>main battery fault or large dip.
>Why were they not charged up when the batteries were showing problems
>earlier?

>If it was not known that this sequence would happen , they why was it
>not known?

Although we had seen the main batteries exhibiting problems the day before 
and begun analyzing the problems and our options, including consideration 
of charging the aux. battery, the command team had absolutely no way to 
know that the battery would fail as rapidly and drastically as it did.  If 
we had been clairvoyant we would have probably charged the aux. battery and 
taken the main battery off line.  The decision to keep the aux. battery 
discharged up to this point was made to prolong its lifetime.

Charging the aux. battery would have accomplished nothing unless the 
shorted main battery were also taken off-line.  Conversely, connecting the 
discharged aux. battery to the mains at the extreme low voltage trigger 
caused no problem, since the voltage level was well below normal charge 
voltage and virtually no current flowed into the aux. bat. during the 
switch-in. The only course of action that would have been helpful, would 
have been to take the main battery off-line and connect the aux. 
battery.  Even in its fully discharged state, the aux. battery would have 
come up to a functional voltage virtually instantly.  With the fantastic 
power of hindsight, we could have altered the extreme low voltage code to 
switch the main battery off-line, or as I've said before, I could have done 
this manually during a 10 minute window when things fell apart and by pure 
luck I happened to be watching the telemetry.  This may seem like an 
obvious idea at the moment, but it was far from obvious at the 
time.  Switching between two separate batteries is never a decision to be 
made lightly.  You may consider this an "oop-sie" that should put my 
anatomy in a wringer,  but I do not.

In satellite commanding, as in my "day job" with sick patients, the end is 
always unpleasant and inevitable.  Our job can never be more than to hold 
off the inevitable for as long as possible.  When the inevitable happens, 
some will feel an irresistible need to "blame".  If it makes you feel 
better to lay blame on someone, the command team, or more specifically, me, 
for not  being able to foresee an instantaneous catastrophic battery 
failure, then I can do nothing to stop you.  However, my conscience is 
clear, and I firmly believe that there is no blame to apportion.  I've 
played the event through many times in my head and I would not have done 
anything differently UNLESS I had a crystal ball.

...and I used to wonder why so few folks were interested in being command 
stations.




-- 
  _______________________________________________________________________
  Stacey E. Mills, W4SM    WWW:    http://www.keplerian.com
   Charlottesville, VA     PGP key: http://www.keplerian.com/key
  _______________________________________________________________________

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