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Re: AO40: status



But under pressure, mmh and n2o4 are liquid.
We have liquid in the tanks.  The stuff
expands in the motor to  change state.  If it
were a gas, the spinning would not really
force the stuff to the "bottom" of the tanks, the
denser gas might settle out but there would
be significant mixing.   Both are liquids.


Bob

----- Original Message -----
From: "Bob Bruninga" <bruninga@usna.edu>
To: "Phil Karn" <karn@ka9q.net>
Cc: <maggie@voicenet.com>; <amsat-bb@AMSAT.Org>
Sent: Sunday, January 07, 2001 9:31 AM
Subject: Re: [amsat-bb] AO40: status


> On Sat, 6 Jan 2001, Phil Karn wrote:
>
> > Nope again. As the propellant drains outward, it gets accelerated by
> > the spacecraft body. This slows down the spin rate. As it dribbles off
> > the end, it continues in a straight line tangential to the point of
> > departure.
>
> Hummh...  You are thinking in terms of a liquid I think.  I am thinking in
> terms of a gas (I assume that all of the liquids instantly vaporize to a
> gas in the vacuum at the point of the leak (near the center of the
> spacecraft).  At that point, the gas is not in contact with the spacecraft
> and so it does not take away any angular momentum as it finds its way out
> of the bird through whatever holes it finds.
>
> Kind of like the fly flying around the cockpit of Lindberg's plane.  Does
> it add to the weight of his plane or not?
>
> But I guess it does take a finite period of time for any molecule of gas
> to get through the compartments and out, and by that time it has picked up
> the angular momentum of that compartment (no matter how small)...
>
> So then it must have all escaped near the center..
>
> > So if AO-40's spinup was caused by the simple movement of propellant
> > mass, it must have moved from the fuel tanks closer to the Z axis.
>
> Yep, we certainly agree on that point.
>
> de WB4APR@amsat.org, Bob
>
> See my APRS LIVE pages    http://web.usna.navy.mil/~bruninga/aprs.html
> See APRS SATELLITES       http://web.usna.navy.mil/~bruninga/astars.html
> See MIM/Mic-E/Mic-Lite    http://www.toad.net/~wclement/mim2.htm
>
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