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Re: amsat-dl statement



Jon Ogden wrote:

> If the computer has completely crashed, there is no
> battery regulation or charging control, etc.  

The BCR does not need the IHU to regulate or control charging. The
IHU is only used for optimizing the battery set-point and solar array
offset voltage to get *maximum* efficiency.. 

> 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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