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Re: Further analysis of the last telemetry from AO-40



I believe that power was being cycled on the
He valves.  They told us they were working on
the propulsion system problem.  I am producing
a table of the values that you produced from
before for the last few minutes of the telemetry
to check for anomalous behavior in the pressure.
Do you happen to have audio from that segment?
If not, does anyone else?

What I think is clear from the telemetry around the
burn is that something is not right with the
regulator.   The low pressure side of the regulator
should be nearly a constant to prevent
adiabatic explansion cooling.  This adiabatic cooling
could explain the longer than normal burn since the
pressure was falling on the low pressure side.   We
definitely have a problem if I am interpreting the
telemetry correctly.   We are going to have to do smaller,
shorter burns if the prop flow pressure regulator
is not working right.  I need to do a calculation or two to
make a SWAG at the temperature drop in the regulator.

I AM GUESSING but this seems to be the right
way of thinking.  Phil Karn and Franklin Antonio
pointed me right to it and asked where the
expansion was taking place.  I looked at the
telemetry and saw the Low pressure side
falling constantly.  It was stupid of me to miss it. 
The temperature didnt drop dramatially in the
Prop and Oxidizer tanks but the fall of 15.2 Bar
to 7.7 Bar on the low pressure side of the
regulator says it "ain't right" since it is supposed
to be REGULATING ;-).

I think I am interpreting these numbers all correctly.
If anyone official wants to point me in a different
direction I will be happy to take the prodding to
stop the idle speculation ;-).

Bob N4HY

----- Original Message ----- 
From: "Richard D. Burgan" <wc8j@raex.com>
To: <amsat-bb@AMSAT.Org>
Sent: Saturday, December 23, 2000 8:24 PM
Subject: [amsat-bb] Further analysis of the last telemetry from AO-40


> Hi all,
> 
> I was fortunate enough to get a copy of the IPS programming
> manual.  With the aid of the manual I went back over the last
> few minutes of AO-40 telemetry.  (The interpretation here is
> very limited since I don't have access to the source code for
> AO-40.  Nor am I any more than a novice with the IPS
> language.)  Here is what I found:
> 
> All of this occurred Wed, Dec 13, 2000
> 
> 11:16:51 UTC I received a telemetry 0 block containing
> "MANY_ARMS ... UNZUL. NAME !"
>     MANY_ARMS is an IPS program (subroutine) that cycles power
> for something.  UNZUL. NAME ! is an IPS error message meaning
> DUPLICATE NAME !
> 
> 11:17:18 UTC an A block of standard telemetry.
> 11:17:32 UTC an A block of standard telemetry
> 
> 11:21:03 UTC a 0 block containing PP2 <DE><A2>p     ...  this
> repeats many times.
> 11:21:15 UTC same as above
> 11:21:28 UTC same as above
> 11:21:40 UTC same as above
> 11:21:53 UTC same as above
> 11:22:06 UTC same as above
> 11:22:18 UTC same as above
> 11:22:31 UTC same as above   Note: this is the last block of
> data from the satellite (that I received)
> 
> The numbers in < > brackets above are HEX numbers.  I have not
> included all the contents of the telemetry blocks for
> brevity.  You can get them from the AMSAT archives if you are
> interested.
> 
> Did some bad code get uploaded?  As a programmer I have to
> admit that I have seen some of my programs do similar things
> when I goofed.  Especially on the old 8 bit machines with
> primitive operating systems, I've seen the console start
> scrolling more than once.  If that's what happened to AO-40
> then I have great hope that a RESET will do the trick.
> 
> Good luck command team!  Thanks for all your hard work!
> 
> 73's de Rich Burgan, WC8J
> 
> 
> ----
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> 

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