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Re: AO40: status



MAJOR point.  I should not have forgotten this.
In fact, it should become the 8-th point in what
heretofore was the 7 point scenario I put up the
other day.

Thanks again Rich for a timely post.

Bob

----- Original Message -----
From: "Richard D. Burgan" <wc8j@raex.com>
To: "Frederick M. Spinner" <fspinner@hotmail.com>
Cc: <amsat-bb@AMSAT.Org>
Sent: Sunday, January 07, 2001 2:03 PM
Subject: Re: [amsat-bb] 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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