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Al, (et. al.),

Thank you for the complementary response.  I wanted to get some facts
out on the AMSAT-BB amongst all the speculation.

In order to properly analyze the possibilities we need more facts and
a lot more experience with the spacecraft.  But its interesting to
The scenario you present doesn't seem probable to me.  Remember that the

telemetry from the satellite continued for 43:14:39 following the second
attempt.  During that period the signals were as predicted, albeit weak
at the
higher than planned apogee.  Although I was out of town I was able to
the Keplerian elements in my tracking program and get good telemetry.

Speculation: I believe that any propellants that exited the engine into
vacuum of space would have vaporized and dispersed rather rapidly if not

burned.  So I don't think they could have caused an explosion or shorted
the antennas.

Just prior to the time of loss of communications the telemetry
contained the following and some ACK frames:

#5050 #DE32 #70A2
PN31F 3 !FK : WAIT10 10 SEK0 ANFANG SU0 @B    ENDE? ;
  0 480 JE PN31F $EBU I + 6 >>> 32 +NUN 0 BLOX 1 - JE

Note: The above frame was received at: Wed, Dec. 13, 2000 11:07:50 UTC
and is an ASCII representation of the frame contents.

I don't know how to interpret this but I think its part of an IPS
language program.
If  I remember correctly the command and control programs for the
satellite are
written in the IPS language.

If the spacecraft was being commanded possibly an error occurred causing
telemetry to stop.

(Wild speculation):  Multiple commands caused a transient.

Speculation OFF: As time goes on and more facts come in I'm gaining
confidence in the situation and the likelihood that the command team
will prevail.
I understand they are being very cautious and trying to preserve data.
I have full confidence in the design and command teams and I support the

conservative approach they are taking.

Richard D. Burgan,WC8J


ALTENCZA@aol.com wrote:

> Richard,
> Your presentation of the AO-40 telemetry preceding the burn
> was excellent! You really helped to present what happened
> and challenged us to explain the event. Allow me the following
> possible explanation in a broad brush sense.
> Since the antennas and the 400 Newton thrust motor nozzle
> are on the same side of the satellite, could it be possible that
> some of the MMH poured out of the nozzle without igniting due
> to a stuck NO2 valve. This may have occurred in the first or
> second burn sequence. Then once some NO2 came out of
> the nozzle, there was partial distributed ignition in the
> vicinity of the antennas. This ignition may have damaged some
> of the antennas. Also, this improper 'burn' may have propelled
> the satellite in the wrong direction slightly. The inclination does
> seem to have gone from approximately 6.5 to 6.2.
> In another version of the upset burn, could it be possible that
> unburned fuel deposited on the antennas effectively shorting
> them out?
> Al   NX2Q

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