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Re: AO-40



On 4 Dec 2005 at 17:29, Greg D. wrote:

> If I recall, the system voltage did not immediately drop to zero, but 
> degraded over a period of minutes.  So it is unlikely that the delta-MM 
> energy came from the battery.
> 
> My interpretation is that some more of the propellant left over from the 
> original "event" mixed and we had a second "event".  That damaged some of 
> the wiring, causing a short and draining the battery.  Without sufficient 
> supply voltage, the radios can't respond, so we don't know what, if 
> anything, is still salvagable.  I can only hope for a little third "event", 
> and an AO-7 style re-awakening at some point in the future.
> 
> Greg  KO6TH
> 
> 
> ----Original Message Follows----
> From: "Luc Leblanc VE2DWE" <luclebla@sorel-tracy.qc.ca>
> To: amsat-bb@amsat.org
> Subject: Re: [amsat-bb] AO-40
> Date: Wed, 30 Nov 2005 00:47:10 -0500
> 
> On 29 Nov 2005 at 17:16, Robert McGwier wrote:
> 
>    We know from an analysis
>  > of the orbital elements following this set of mission ending events that
>  > something happened to significantly change the mean motion.  AO-40 is a
>  > big spacecraft so it must have been quite a bit of energy.
> 
> Can we safely assume that this "something happened to significantly change 
> the mean motion releasing quite a bit of energy" can be interpreted
> at the user end as an EXPLOSION probably due to the connection of a good 
> battery on a shorted one?
> 
> That's this side of engineering world i like.. instead of using one word 
> they used 13 but the end result is the same BOUM! :). Not really as
> there is no sound propagation in space.
> 

Thank's for the info's Greg. Here is what is puzzling me?


AO-40 Update - 9 March 2004

Gentlemen,
Today during the period 0310 to 0320 UTC (orbit 1541) I observed the following.

Prior to issuing the command sequence we tune around the beacon frequency, taking note of the "noise spectrum". No variance in amplitude 
detected, just clean white noise. At 0310, commenced sending a 12 block sequence, 3 * (Reset,Tx-Off,Reset,Tx-On).

At the completion of the sequence, again tuned around the beacon frequency, and noted a noise peak of 4 to 5 db, in the vicinity of expected 
beacon frequency. The width of this peak was about 5 kHz. Listened to it for about 15 seconds and then sent a Reset, Tx-Off command and the 
noise peak disappeared, approximately 2 seconds after the Tx-Off block was completed.

Completed my session with a number of Aux-Batt commands, but did not attempt the Tx again. Range was nominally 12000/15000 kilometres during 
command period. Was using my last calibrated uplink frequency.

This tends to suggest that the IHU and L Band Rx are operational. Bus voltage insufficient to open that damn relay. Considering SA=-72, the 
remaining cells are holding up well. Hope this makes your day, like it has mine.

Colin Hurst, VK5HI
for the AO-40 Command Team 




"-"
"It is not the class of license the amateur holds, but the class of the amateur that holds the license."

Luc Leblanc VE2DWE
AMSAT 33583
www.qsl.net/ve2dwe 
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