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Re: AO40: status



Hi All,

Remember that the spin up did not happen at the same time as either of the
burns.  The telemetry showed the spin rate being the same before, during, and
for 43 hours after the last burn.  The increased spin was first noted after the
restoration of communications on Dec. 25, 2000.  I'm going back to look at the
very last telemetry before the comm loss to see if I can find any change in spin
rate.

73's de Rich @ WC8J

----

"Frederick M. Spinner" wrote:

> OK, the next question would be:
>
> Since we know the difference in orbit, and the mass of the satellite, etc.,
> then we could calculate what the spin should have been based on the burn we
> got.  Take that number, subtract it from the measured spin of 17 RPM,
> reverse the above calculation could we get a semi-exact amount of mass loss
> after the burn stopped this way?
>
> I'm sure those more intelligent than myself have done this calculation
> already, but I think I'm close to understanding this theory now.  :-)
>
> Is it possible that fluid kept coming out of the motor after the burn
> stopped-- instead of a "split" or "leak" somewhere in the system?
>
> Fred W0FMS
>
> >From: "MCGWIER ROBERT" <rwmcgwier@home.com>
> >To: "Frederick M. Spinner" <fspinner@hotmail.com>
> >Subject: Re: [amsat-bb] AO40: status
> >Date: Sun, 7 Jan 2001 09:48:33 -0500
> >
> >Yes it speeds up as a matter of course during
> >a normal burn as the moment of inertia decreases
> >with decreased mass out near the perimeter.
> >Remember the "bottom" of the tanks are towards
> >the walls since the spacecraft is spinning.
> >
> >Bob
> >
> >----- Original Message -----
> >From: "Frederick M. Spinner" <fspinner@hotmail.com>
> >To: <amsat-bb@AMSAT.Org>
> >Sent: Sunday, January 07, 2001 8:17 AM
> >Subject: Re: [amsat-bb] AO40: status
> >
> >
> > > Wouldn't that imply that even a normal burn would increase the spin
> > > rate?  If so, has experience shown that in the past on other satellites
> >that
> > > this happens?
> > >
> > > Fred W0FMS
> > >
> > > >Whoaa, how about this!  Doesnt matter where the leak is.  If we have a
> >500
> > > >Kg spacecraft spinning at X RPM, and then release say 250Kg of its mass
> > > >(lost propellant) then conservation of angular momentum will require
> >the
> > > >satellite to spin up (double its speed all else being equal (its not),
> > > >but close enough)...
> > > >
> > > >Its not that the mass had to move to the center like a spinning skater
> > > >which is a change in moment of inertia, but a loss of mass with no loss
> >in
> > > >angular momentum.  Thus it must spin up.
> > > >
> > >
> > > _________________________________________________________________
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> > > ----
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> > >
> >
>
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