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Re: pt3 telemetry



Jon:

First let me say that I am reading telemetry.  Dorgan gave
me a huge piece when he pointed out the IPS program
being sent in telemetry. I have no official or unofficial
status.  I speak for no one,  nor any entity.  Do not read
anything into the fact  that I was once a director and an
officer of  AMSAT.  It means nothing after 10 years.
In fact, all of those officials who still talk to me are begging
me to be careful and silent.  The rest don't speak to
me at all.  Let's start.

There are several kinds of valves in the
propulsion system. Some are pneumatic.  That
means they need pressure to operate. Some are
failsafe valves.  That means, when the pressure
falls too low, they close.  Here is a scenario that
explains everything seen and based on a totally
unofficial reading of the diagrams published
in AMSAT publications.  The most critical portions
of this, the very foundation of it in my opinion, are
(4) and (5).  I did not come up with these, they
came from a good friend of mine who is also an
outsider in all of this.  This person will speak when
and if they choose to do so.


(1) Faulty PN sequence is sent.  System fails to
      pressurize.
(2) Correct PN sequence is sent, system
      pressurizes and operates.  Motor burns.
(3) Telemetry shows pressures after the
      regulator are and the regulator is failing
      to keep the low  pressure up.
(4) The pressure falls below the point where the
       pneumatic valves  that  shut off the flow of
       propellant and oxidizer to the motor will
      operate.
(5) The pressure continues to fall since these
       valves are stuck open and  isolation valves,
       which need pressure to stay open, now
       automatically shut three minutes late.
(6) Pressure on the low side builds and the LIU
      successfully closes the pneumatic valves.
(7) Falling pressures in a sealed system screams
      leak.   No other evidence of a leak is seen so
      probably a leak is doubted and since we have
      had a failure of the He valves in the integration lab,
      we incorrectly attribute the failure to them.
(8)  The leaking hydrazine does not do any damage at
       all during this first event set. Why? The motor is
       successfully operating and we are accelerating
       away from the leaking gas which is escaping past the
       motor bell.   This leads one to believe that the leak is
       likely in the cooling jacket which cools the motor bell
       and is carrying hydrazine.
(9)  The second round of events start when a program is
       uploaded to try and correct what hindsight probably
       shows is the incorrect deduction from (7).  A major
       propellant leak occurs and eats away at harnesses
       in the spacecraft.  This failure mechanism is
       unfortunately  extremely well known to me.  I had to
       explain a failure of a really expensive piece of
       hardware that this happened to. It has also happened
       in commercial birds.  In one in particular, it just kept
       leaking and eventually ate one harness after another
       until all was lost.  This explains the loss of widely
       separated sensors.  Their signals are carried to the
       instrumentation package by a harness which is now
       partially eaten and one or more things fail and cause
       some kind of IHU event which causes it to go off line
       or the 2 meter transmitter to fail.

Nothing good comes from this scenario.   I would love only
slightly less than my German friends for this to be totally
full of material studied by scatologists.


Bob
N4HY

----- Original Message -----
From: "Jon Ogden" <na9d@mindspring.com>
To: "MCGWIER ROBERT" <rwmcgwier@home.com>; <amsat-bb@amsat.org>
Sent: Friday, January 05, 2001 10:23 AM
Subject: Re: [amsat-bb] pt3 telemetry


> on 1/5/01 6:31 AM, MCGWIER ROBERT at rwmcgwier@home.com wrote:
>
> > As I stated, I believe we leaked propellant.   I believe this explains
> > why the burn went long, why the regulator didn't regulate, why
> > the electronic failures occurred, etc.
>
> First of all, Robert, I have a problem with speculations.  We had plenty
of
> these when the bird first went silent.  I have an issue with the idea of a
> propellant leak.  Here's why:
>
> 1.) You say the leak caused the burn to go long.  Why would it do that?
If
> the leak is say in some of the plumbing inside one of the bays of AO-40,
> what does a leak have to do with the length of the engine burn?
>
> 2.) I must admit that I am a novice on the propulsion system, but just
> putting two and two together, if the leak was somewhere between the fuel
> tanks and the regulator valves, wouldn't we still see the leak as
occurring?
> And if the leak is after the regulator valves, are those valves in a
> position where said lead would cause possible damage to the craft?
>
> 3.) If the leak was after the regulator valves, I would expect a SHORTER
> engine burn since some of the propellant slated for the engine would have
> leaked away.
>
> 4.) Is the LIU or anything related to the valves/fuel system near the 2
> meter transmitter?  I don't have my spacecraft drawings handy, but one
would
> expect the leak to have damaged components near by.  If the two meter TX
is
> not near the fuel system, then how did the fuel leak damage it?
>
> 5.) From what I have read from the control team, it appears that systems
in
> various areas of the spacecraft have been affected.  If indeed it was a
> leak, I would think the majority of problems would be in one particular
area
> or at least concentrated there.  This does not appear to be the case.
>
> 6.) Why would a propellant leak cause the IHUs to crash?  I suppose that
if
> the leak caused a failure to the 2m TX then perhaps bad internal data fed
to
> the IHU caused it to crash.  That would seem like pretty poor software and
I
> think we would do a better job than that.  The IHUs weren't damaged by
> whatever happened as far as we know since they are working fine now.  So
why
> did they crash?  If a leak did happen damaging the 2 meter TX then the
> beacon would have gone off the air.  But the IHU should have stayed up and
> eventually gone into command-assist, but it did not.
>
> To me I think something else happened.  I still like the theory that it
was
> some sort of solar particle(s) that caused all this to happen.  Let me
> speculate:
>
> A proton event occurred that overloaded the systems on the spacecraft.
This
> sort of overload/interference cause the IHUs to crash thereby taking the
> spacecraft off line.  Additionally, with the IHU in an unknown, random
state
> various bogus commands could have been sent to different systems in the
> craft.  Perhaps the magnets or the momentum wheels were turned on and that
> increased the spin.  An electromagnetic event like this could damage
sensors
> in a random fashion or it could "uncalibrate" them.  It could damage RF
> components, etc.
>
> Of course, this could all be Sci-Fi and my idea totally flawed for one
> reason or another.  And maybe my above conclusions about the propulsion
> system are inaccurate as well.  They are just questions based on what I do
> know (which isn't necessarily much!).
>
> Lastly, I am bothered significantly by the two meter TX issue.  If it
wasn't
> damaged then what would have kept it from turning on when the reset
command
> was sent?  I can't think of anything in either the propellant or "proton"
> scenarios that would have kept an undamaged two meter TX from coming back
on
> line.  With the problems seen with the UHF TX it is a shame if both low
band
> transmitters are off line.  Now it's really a shame that the 10 meter TX
> wasn't finished!  Again, this is all speculation and things may be fine
with
> the 2 meter TX.  We will just have to wait and see.
>
> 73,
>
> Jon
> NA9D
>
>
> -------------------------------------
> Jon Ogden
> NA9D (ex: KE9NA)
>
> Member:  ARRL, AMSAT, DXCC, NRA
>
> http://www.qsl.net/ke9na
>
> "A life lived in fear is a life half lived."
>
>

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