[amsat-bb] Re: AO-51 current status

Andrew Glasbrenner glasbrenner at mindspring.com
Fri Nov 25 14:39:08 PST 2011

Next pass the repeater was still on but that the very low power levels 
we saw earlier. I crashed the IHU and attempted to restart, but ran out 
of elevation. More after tomorrow's afternoon passes.

Just as an FYI, and to answer some emails sent privately to me, 
AMSAT-Fox is designed to continue in "zombie" mode despite a battery or 
IHU failure, while maintaining control to FCC standards. See page 4 of 

73, Drew KO4MA

On 11/25/2011 4:25 PM, Andrew Glasbrenner wrote:
> Sometime between 1815 and 1945Z today, AO-51's IHU crashed. This 
> happened after a few days of intermittent and unpredictable operation. 
> Mark N8MH and I reset the satellite and started the repeater back up 
> around ~2030Z, and lowered the output power to about 300 milliwatts. 
> Battery voltage was low, around 4.9v, with cell 1 less than 1 volt. 
> This is very troublesome, as the impending third cell failure will 
> likely end our continuing operations, particularly if it fails shorted 
> as the others have. We've also observed the transmitters cutting off 
> around 4.7 to 4.6 volts prior to the last reset, in eclipse.
> We'll do what we can, but her days are short. Let me ask once again 
> for more reports, especially from the US operators, to the 
> oscar.dcarr.org webpage. The command stations monitor this for changes 
> in the operation of AO-51, and while worldwide participation is good, 
> few US operators post to it.
> Please support the several satellite programs worldwide, such as 
> AMSAT-Fox, AMSAT-UK FunCube and UKCube, AMSAT-ZL Kiwisat, AMSAT-DL 
> P3E, and others.
> 73, Drew KO4MA
> AMSAT-NA VP Operations
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