[amsat-bb] Re: Less than lightening Results

Greg D. ko6th_greg at hotmail.com
Fri Apr 10 20:19:23 PDT 2009


Hi Sebastian,

Filling in the details from others...

AO-10 is still in orbit, but the electronics appear to be mostly toast.  The control computer was fried by radiation years ago, due to it being in an odd orbit because of a partial booster failure.  The radios still worked for a while, but it was became erratic with good days and bad, more bad than good.  Last time it was heard was a number of years ago, but there's still a chance it will be heard from time to time.

AO-13 is no longer in orbit.  Both AMSAT and NASA learned that there are some orbits that don't last long, because of a "resonance" in the timing of their orbit compared to the orbits of the Moon and the Earth going around the Sun.  The result was that the satellite got a little "cosmic tug" in its orbit, slowly pushing it into the planet below.  Not good.

Many others have been lost due to battery or electronic failures, including for a while, AO-07.  But after 21 years on the "dead" list, AO-07's batteries opened up and the electronics (which somehow survived all those years) woke back up on solar power alone.  

Greg  KO6TH


> From: w4as at bellsouth.net
> To: AMSAT-BB at amsat.org
> Date: Fri, 10 Apr 2009 14:00:19 -0400
> Subject: [amsat-bb] Re: Less than lightening Results
> 
> They say that no question is a dumb question, so here goes - since I  
> haven't seen this discussed before, but maybe I missed it.
> 
> What makes AO-7 so special?  Why is it that we lost AO-10, AO-13 and  
> all the others in the past several years, yet this one is still  
> working?  I know the batteries are dead, but I'm primarily interested  
> in how this bird is able to stay in it's orbit for over 30 years?  And  
> if it's orbit is decaying, how is it that it has apparently decayed so  
> slowly?
> 
> I was under the impression that unless a satellite is occasionally  
> 'boosted', it will eventually re-enter?  I somehow doubt AO-7 has any  
> fuel left in it's boosters; if it had any.
> 
> 73 de W4AS
> Sebastian
> 
> On Apr 9, 2009, at 11:01 PM, Greg D. wrote:
> 
> >
> > Yeah, this is one grand old bird (the satellite, I mean).  If you  
> > look at the planetary statistics, the median age of the human  
> > population is about 26.8 as of 2000, and growing slowly.  That makes  
> > AO-07, at age 35, significantly older than more than half of the  
> > people on Earth.
> >
> > Greg  KO6TH  (one of the few older than AO-07...)
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