[amsat-bb] AO-92

[Bill Gaylord]

Didnt AO-85 cells fail due to over heating? Maybe the cell dying on AO-92
was just weaker then the others.

Or maybe the L/U mode strained them more? As that was a key difference
between AO-85 and AO-92. Does AO-91 have L/U i dont recall if it did.

KD9kCK


On Mon, Sep 14, 2020, 6:07 PM Andrew Glasbrenner <glasbrenner at mindspring.com>
wrote:

> A few factors probably involved:
>
> AO-85 saw less use due to being a little harder to access. It was also in
> a higher orbit, that wasn’t sun-synchronous with a near 12 o’clock LTAN, so
> it saw more sunlight.
>
>
>
> 73, Drew KO4MA
>
>
>
> *From:* Bill Gaylord <chibill110 at gmail.com>
> *Sent:* Monday, September 14, 2020 6:31 PM
> *To:* Andrew Glasbrenner <glasbrenner at mindspring.com>
> *Cc:* Roy Dean <royldean at gmail.com>; AMSAT BB <amsat-bb at amsat.org>
> *Subject:* Re: [amsat-bb] AO-92
>
>
>
> Just wondering why AO-92 is failing so much quicker than AO-85. AO-85
> lasted about 4 years in space till it went silent / started having battery
> issues. AO-92 has only been in space for about 2 and 3/4 years.
>
>
>
>
>
>
>
> AO-91 seems to be doing okay. Or at least I haven't seen anyone talking
> about it going into safemode. And I haven't heard it in safemode.
>
>
>
> 73
>
> William KD9KCK
>
>
>
>
>
> On Mon, Sep 14, 2020 at 5:14 PM Andrew Glasbrenner via AMSAT-BB <
> amsat-bb at amsat.org> wrote:
>
> I've mostly been posting about it on Twitter.
>
> AO-92 has a cell that's failing, and towards the end of many eclipses it
> goes into auto-safe mode at 3.6v. If the battery drops low enough the IHU
> resets, and it comes back up in normal safe mode. Mark and I have been
> commanding to repeater mode on the first available pass after the resets,
> but it's not a long term sustainable answer. Last night Mark commanded the
> transmitter completely off while we consider a plan of action.
>
> Leaving autosafe on and the tx off, we may be able to turn the repeater on
> ad-hoc for weekends or such, completely dependent on command station
> availability. Turning autosafe and the IHU off like we did with AO-85 will
> kill the satellite pretty quickly, so that's not a good response either.
> So,
> we'll look at resets and battery states before this weekend and see where
> we
> stand.
>
> 73, Drew KO4MA
> AMSAT VP Operations
>
> -----Original Message-----
> From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of Roy Dean via
> AMSAT-BB
> Sent: Monday, September 14, 2020 4:55 PM
> To: amsat-bb at amsat.org
> Subject: [amsat-bb] AO-92
>
> I can find no information about AO-92 going silent recently.   Was it
> commanded into a silent state (as AO-85 was shortly before it went silent
> permanently)?
>
> --Roy
> K3RLD
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