[amsat-bb] Re: Can we get them to fix AO-40 first then?

tosca005@umn.edu tosca005 at umn.edu
Fri Oct 16 07:44:41 PDT 2009

On Oct 15 2009, Edward Cole wrote:

>So, IF the battery un-shorts, IF the IHU boots 
>and resets the beacon (S-band, I 
>assume).  Therefore, for the rest of us, 
>occasional monitoring the beacon frequency would 
>be good (using the current keps to estimate 
>Doppler offset).  IF detected, then commands 
>could be attempted.  Sounds like a lot of 
>IF's.  Is this a good reason to keep your S-band 
>downlink equipment working?  Think about it.
>Integrity of S/C is unknown, so its all a big guessing game.
>I remain available (when QRV on L-band with 865 
>kW EIRP) for command attempts (lat=60.675N, Lon=151.316W).
>73, Ed - KL7UW

Perhaps my analogy to a comatose patient was a little bit off the mark, in 
that I was trying to say that just having a command station turn on their 
equipment, point their antennas, and give the command to release the solar 
panels did not have a high probability of success.

What I neglected to say, since I had incorrectly assumed that everyone on 
the list already knew it, was that ever since AO-40 went silent for the 
last time, at least one command station has regularly been sending commands 
to the old gal, not with the intent of releasing the solar panels, but with 
the intent of at least getting her interacting with the command station and 
doing things like turning on the S-band transmitter to get some telemetry, 

Peter also mentioned in one of his recent posts that command station(s) 
still do this on a regular, although perhaps less frequent, basis.

As has now been described, if the batteries STOPPED presenting a dead short 
to the power bus, unlike AO-7 which simply came alive, AO-40 would probably 
NOT automatically announce its re-birth, because the default beacon (2 
meters) is not functional. It would take a command from a command station 
to turn on the S-band transmitter for anyone (like a command station 
operator) to know that she was capable of listening any more. So, even 
though it is a low probability scenario, it is still worth sending the 
appropriate commands to AO-40 on a regular basis just on the off chance 
that she had emerged partly from her coma.

It's pretty inexpensive to simply send some RF with appropriate commands 
her way, so there is very little downside to trying. I know that AMSAT 
doesn't give out command information freely, for obvious reasons, but there 
were several control stations active when she was alive, and adding one or 
more staffed by reliable folks who can be trusted with the information 
should be possible. . .

Do I hear someone volunteering?  :)

73 de W0JT

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