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



This is a good thread.
I'm speaking of as a newbie here because I've haven't looked at the IPS 
manual. If IHU-1 crashed it could have been cause by a sensor somewhere in 
the propulsion system returning a voltage out of range of what was 
expected. The software didn't know how to deal with it, which resulted in a 
system crash. It's also possible the IHU didn't know how to deal with 
unexpected information it was getting from the pressure sensors. Just a 
thought.

At 10:01 PM 12/23/00 -0500, "MCGWIER ROBERT" <rwmcgwier@home.com> wrote:
>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
> >
> >
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
>
>----
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