Auke de Jong,
I believe AO-40 was designed by AMSAT to not allow both sets of batteries to be disconnected. We should have learned with AO-7 that every satellite should be able to work on solar power alone as eventually all batteries will fail. It is my understanding that the only chance we have is if the batteries burn open some day in the future.
Someone else my be able to correct my understanding if I have misunderstood the AO-40 design. Hopefully those who designed the power system have moved on and we now have some better insight.
Don -----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Auke de Jong, VE6PWN Sent: Saturday, March 01, 2008 7:53 PM To: AMSAT-BB Subject: [amsat-bb] recent AO-40 efforts?
I noticed that during the last period of documented efforts to recover AO-40 4 years ago, there were promising results about hearing faint signals. By my interpretation of those old reports, they basically confirmed that the command receiver was working but could not get much else done with it. Now that it has been officially silent for several years, has anyone tried to send commands to it in order to disconnect the (shorted) battery banks via the relays onboard? Given the changing sun-angles on the arrays and the passage of time, as well as possible heating of certain onboard components due to the constant supply of solar power to the shorted batteries, could there be any possibility of (energizing) the battery-disconnect relays? I presume that they are in a fail-close arrangement, because if they were fail-open, they should have already done-so due to the shunted power system. Also, could the solar panels have fuses that have opened? could such fuses be re-settable?
I would be interested to hear what knowledge there exists about the present status of AO-40, especially what "google" couldn't fetch.
Auke de Jong VE6PWN DO33go Edmonton, AB
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