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Re: pt3 telemetry



on 1/4/01 7:58 PM, Richard D. Burgan at wc8j@raex.com wrote:
 I saw an AMSAT-BB post yesterday where Phil, KA9Q calculated the
> doppler at +/- 14 Hz.  All the indications I had were that it is more than
> that.  So there is something going on.  I roughly measured the rotation rate
> at
> 17.4 rpm.

I think Phil was talking about frequency drift from the rotation of the
spacecraft not the Doppler from the normal fact that the satellite is moving
relative to us in its orbit.

> 
> I am curious about the following questions (among others):
> 
> 1. How did the spin rate get from 9 rpm to 17 rpm?  Where did the energy
> come from?

That is unknown as of yet.  The control team acknowledges that the spin rate
shown in the telemetry does not match that calculated by receiving the
signal and measuring it like you did.  They have not said what happened.

> 
> 2. What happened to lower the Helium pressure between burn attempts?

Not sure what you mean.  The He pressure after recovering the bird has shown
to be right where it should be.  In between burns there really was no helium
release since the valves didn't open correctly for the first burn.  The only
helium release was for the second burn.  At least this is how I understand
it.

> 
> 3. Do other stations here the same audio pattern?

Don't have mode S capability yet.  :-(
> 
> 4. How could we accurately measure the "doppler" wobble from AO-40?

I think Phil pretty accurately calculated it.

> 
> 5. What do the propellants do to wiring and other spacecraft structure if
> they leak?

Probably something that is not very good.  From what I've read it seems like
the MMH is pretty reactive.  To me that would mean that any of the
propellants that might leak could be pretty corrosive and destructive to
circuits, etc.  But we've not been given any indication that this is what
happened.

> 
> Lets hope we get some more information soon!  That would be GOOD news.

Well, let's hope we get GOOD news in that information!  :-)

73,

Jon
NA9D


-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."

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