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@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@gmail.com *Sent:* Monday, September 14, 2020 6:31 PM *To:* Andrew Glasbrenner glasbrenner@mindspring.com *Cc:* Roy Dean royldean@gmail.com; AMSAT BB amsat-bb@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@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@amsat.org On Behalf Of Roy Dean via AMSAT-BB Sent: Monday, September 14, 2020 4:55 PM To: amsat-bb@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 _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb