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Re: AO40: status

In my previous message, I said I thought there
might be a leak in the motor casing from the
coolant jacket.

This is another thing that should have slapped me
in the face.

It is clear we have increased  the rotational rate
as everyone has noticed.

Furthermore it is clear that it the increase in
angular momentum has occurred around the
Z axis since the spacecraft does not appear
to have an appreciable wobble.  The only
place I can see from a quick look for this
to happen is in the tubes that flow propellant
around the motor casing.   Given the nearness
of this to the axis and the fairly large moment
of inertia and the rate at which it was expelled
much have been pretty high.  I feel we have been
extremely fortunate indeed that the increase in
rate was in the direction of rotation we had already
established.  If it had not been, we might have
stopped rotation, solar panels not toward the
sun or long periods of no sun and this would
have been really difficult to recover from with
no attitude sensors in operation (dependent
on motion for a signal).  There might be other
places where we could have applied torque
around the existing spin axis but I can't see it

Peter, thank you very much indeed for your
message.  We are wishing the command team
all the luck in world.


----- Original Message ----- 
From: "Peter Guelzow" <Peter.Guelzow@arcormail.de>
To: <amsat-bb@AMSAT.Org>
Sent: Friday, January 05, 2001 12:37 PM
Subject: [amsat-bb] AO40: status

> Dear All,
> I know that many people are looking for more information and
> I can understand this..
> But please keep in mind that the recovery efforts are not easy 
> and take a lot of time. Everyone involved in the recovery
> is indeed very busy.. and we all have another job for living..
> Due to the currently limited downlink capabilities, uploading
> of new command and analyzing the results takes somewhat longer
> at the moment.
> So far it was determined that the L-band and U-band Uplink,
> both on HiGain antennas, seem to be OK.  We have no results
> yet on the Omni antennas.  At the moment command stations
> will also evaluate the V-band antennas with the receivers.
> As soon as the antenna situation (including the antenna relays)
> is known, we will also carefully try the V-band (2m) TX again, maybe
> even the U-band (70cm) TX.  Until than we will continue to use
> the S2 downlink.
> Another high priority is to test the magnetorquing attitude control
> system to spin down the s/c and adjust the attitude for better
> sun angle and also to improve the squint.
> Than it will also take some time to evaluate the status of the
> various other systems and experiments. This will certainly include 
> the Arcjet and the wheels as earliest as possible.
> Once this is completed and we have a complete overview, than
> we can declare the spacecraft to work normally and perhaps 
> think about re-defining the mission of AO-40, whatever it will 
> be...
> The good thing is, that AO40 seems to be in a very stable condition
> and there are no signs on further damages. However, there is a
> sign of a small leak, which is also the reason for the higher spin.
> The reason for this, effects and other things are under investigation
> and results will be reported when a final conclusion is made.
> At the moment we clearly have priorities and these are to bring
> AO-40 back into "normal" mode as soon as possible.
> Best regards
>   Peter DB2OS
> ----
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