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AO-40 info from AMSAT-UK



The following appears on the AMSAT-UK web site at
http://www.uk.amsat.org/phase3d.htm and provides additional information on
the command-assist watchdog timer mechanism, and that a system RESET issued
from ground is something that would take place at some point in the future -
but not yet .... Ed, KF7VY, http://hamradio-online.com
---------------------------

Post-launch info 2330 utc 17 December
No news. Amsat-DL are saying, basically, the same but with this rider from
DB2OS via amsat-bb:

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...

We also got reports that some 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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