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@bellsouth.net To: AMSAT-BB@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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