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Tumbling bright satellite: possibly Zi Yuan 2 or Cosmos 1689 Rocket

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Alexander Avtanski

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Aug 12, 2007, 6:26:49 AM8/12/07
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Hello,

Does somebody know if Zi Yuan 2 or Cosmos 1689 Rocket is tumbling?
Period about 6 sec (+/- 2 sec), very pronounced sequence of one bright
peak and one less bright peak. Something like this?

I'm asking because today we saw an unusually bright tumbling satellite
and heavens-above.com shows two very similar passes by Zi Yuan 2 and
the Cosmos rocket. Both fit the trajectory and are within the accuracy
limits of the time we took (we did not have exact time at the moment;
probably +/- 3 minutes). I'd like to see that one again.

Thanks,

- Alex

mol...@hotmail.com

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Aug 12, 2007, 7:53:25 AM8/12/07
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On Aug 12, 6:26 am, Alexander Avtanski <avtan...@gmail.com> wrote:
> Hello,
>
> Does somebody know if Zi Yuan 2 or Cosmos 1689 Rocket is tumbling?
> Period about 6 sec (+/- 2 sec), very pronounced sequence of one bright
> peak and one less bright peak. Something like this?

I have reviewed many observations of Cosmos 1689 r (85090B / 16111),
as far back as 1990, almost all of which report steady brightness.
There was one report, in spring of 2007, of a 60 s variation, much
slower than your observation.

I found only a few observations of Zi Yuan 2 (03049A / 28057), made in
2004-05, which reported steady brightness.

Since 03049A has seldom been observed, and not recently, it is more
likely to be an undiscovered flasher than 85090B. It is a fairly young
spacecraft, but it could have failed prematurely. I have not attempted
to find out its health, so that is only speculation.

Please let us know the results of any further observations you may
make of 03049A.

Ted Molczan

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