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Re: amsat-dl statement



Peter,

Thanks for the explanation.  You seem quite confident and not in a hurry at
all to try to get AO-40 back on line.  But I have a couple of questions:

1.) You say that performing a "reset" from the ground is a drastic step and
the controllers do not yet want to take that step.  Why is it a drastic
step?  Will you then lose all collected data about what happened?  Is that
the reason?  How is the hard reset from the ground different from the reset
that the watchdog performs?

2.) In my mind I am thinking many possible scenarios about a software
watchdog and the IHU-1 crashing.  If the IHU has crashed, you state below
that a hard reset will be needed and that can be sent from the ground.  That
makes sense.  However, what if in that computer crash, the receivers of the
satellite are all switched off?  Then sending commands from the ground will
be useless.  Or can all receivers being switched off not happen?  Secondly,
if the IHU-1 is crashed, then how can the reset command be interpreted by
the spacecraft?  Is there some other processor that recognizes the reset
command?

I appreciate the confidence you show.  It appears that you feel that things
are well under control all happening according to a specific time table of
events.

Given that we are now in a "waiting game" for these various software timers
to trigger, perhaps we can hear some more from the control crew about some
of the various things that have been going on with the bird:

1.) Any info on what caused the telemetry to stop
2.) What tests were being performed on the engines
3.) Any ideas as to why the burn went longer than it should have
4.) Specifics on how this watchdog timer works and how the reset works

There are probably additional things others could add, but there is a lot of
info that could be shared with the ham community at large about the bird.
Many of us are beginning to think that it is dead.  Your response shows that
the control team is confident that you can get the bird back.  A strong
detailed explanation from the team on what the time table and procedures are
and why would go a LONG way to quelling rumors and fears rumbling around.
We are in a position now were official information is very important.  I was
one of the ones trying to "keep the dogs at bay" previously on released
information because you guys have been so busy.  However, if we are just
waiting for things to happen now, then can we get some more information?
Many of us have been feeling sick and depressed all weekend because of what
has happened.  If that can be alleviated, then we are all better off.

My comments about the apparent death of our baby are not meant to be
criticisms at the control or design crew.  You guys have done a fantastic
job and I am still behind you guys.  I do appreciate the time and sacrifices
you guys have made.  One word from the control crew can give us all great
confidence.

Good luck in getting our bird back.

73,

Jon
NA9D

on 12/17/00 4:26 PM, Peter Guelzow at Peter.Guelzow@arcormail.de wrote:

>> Again, flame me if you want, but it's a little difficult to hear the
>> designers of the craft telling us that it will reset itself but that they
>> just don't know when.  Huh?  They designed the circuits with certain
>> parameters.  I don't know, I am just bummed and depressed.
>> 
> 
> This is also not correct and there might be a misunderstanding.
> 
> A timeout was expected on Saturday. There were no observations and
> command stations tried to re-establish communication by sending
> blind commands.
> 
> Assuming that no commands have been accepted by the IHU-1 since contact
> was lost on Wednesday, a COMMAND-ASSIST watchdog will be invoked
> at orbit=65, MA=0 which is 2000 Dec 21 [Thu] 23:55 utc.
> 
> The COMMAND-ASSIST routine will cycle through various RX, TX, Hi-gain
> and Low-Gain antennas..
> 
> If commands were received by the spacecraft (although we have not
> seen any successful commands so far), than the COMMAND-ASSIST watchdog
> will be reset for another 10 orbits. In this case we may see this function
> happen not before Dec 25.
> 
> Please note that this is a *software* watchdog. There is no hardware
> watchdog. If the IHU has crashed, than a RESET command can be issued
> from ground. This would be the last resort. It is a very fail-safe
> system, which has been used before on AO-10 and AO-13.
> However, it was decided to check and analyze all other possibilities
> before issuing such a drastic command. There is no need to hurry and
> we don't want to miss any option...
> 
> 
>>> There are various serious reports about very weak PSK signals which
>>> seem to be coming from AO-40. The commandteam is verifiing these reports..
> 
> We also got reports that these signals might be "fake" PSK signals sent
> by someone through AO-10, which was visible at the same time.
> 
> The command team is still very interested in any signal report, but please
> make sure that these signals come from the right direction, etc..
> 
> 
> 73s Peter DB2OS
> 
> 
> ----
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-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

My President is George W. Bush -> The legal winner in Florida

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