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Re: AO-40 Attitude Information



Hello Peter and Stancey,

The S/C attitude for january 12/13 seem good for trafic.
AO40 transponder will be open for an expedition on devil island ( IOTA
SA020) with FY5KE kourou radio club ?

Happy new year

FY1DW Norbert

----- Original Message -----
From: Peter Guelzow <peter.guelzow@arcormail.de>
To: <amsat-bb@AMSAT.Org>
Sent: Saturday, December 29, 2001 2:02 PM
Subject: [amsat-bb] AO-40 Attitude Information


>
> Dear All,
>
> May I take this chance to say a big thank you to our command stations
> James Miller G3RUH, Stacey Mills W4SM, Ian Ashley ZL1AOX, Graham
> Ratcliff VK5AGR, and all those who support them with telemetry, for
> an outstanding effort in keeping AO-40 operational and work as it's best.
> Special thanks also to Paul Willmott for keeping the telemetry archive
> up to date and organizing all the mass of telemetry data.
>
> HAPPY NEW YEAR to everyone!!
>
> best wishes
>  Peter
>
> --
>  Peter Guelzow, DB2OS
>  Pres. AMSAT-DL
>
>
>
> The following information is provided by G3RUH:
>
>
____________________________________________________________________________
__
>
> AO-40 Attitude Information
> --------------------------
> The YACE camera was activated on Orbit 535 in order to check the AO-40
> attitude.
>
> This is done every 5 orbits which also enables calibration of the excess
> precession in ALON (the so-called "Mystery Effect").
>
> Presently the Sun sensors cannot see the Sun, so the Sun/Earth sensor
system
> is unuseable.  This "hibernation" commenced on orbit 529 (Dec 24) and will
> continue until orbit 549 on 2002 Jan 09 [Wed].  You can tell that this is
the
> case because the telemetered analogue spin rate is meaningless;  the true
> spin rate is in fact 2.51 rpm.
>
>    Today Dec 29 on orbit 535 the attitude measured  ALON 327.4, ALAT -11.4
>                  with an uncertainty of order 0.1 deg.
>
> The attitude direction will drift as follows:
>
>                                       Sun  Illumin-
> DATE                  ALON   ALAT    Angle  ation %
> ---------------------------------------------------
> 2001 Dec 20 [Thu]    347.5  -10.2    -37.2   79.7
> 2001 Dec 21 [Fri]    345.7  -10.2    -39.0   77.7
> 2001 Dec 22 [Sat]    342.2  -10.2    -41.8   74.5
> 2001 Dec 23 [Sun]    340.3  -10.3    -43.5   72.5
> 2001 Dec 24 [Mon]    338.5  -10.3    -45.1   70.6  << Sun sensor stopped
> 2001 Dec 25 [Tue]    336.6  -10.3    -46.5   68.8      ..    ..     ..
> 2001 Dec 26 [Wed]    333.1  -10.3    -48.6   66.2      ..    ..     ..
> 2001 Dec 27 [Thu]    331.3  -10.3    -49.7   64.7      ..    ..     ..
> 2001 Dec 28 [Fri]    329.5  -10.4    -50.7   63.4      ..    ..     ..
> 2001 Dec 29 [Sat]    327.6  -10.4    -51.5   62.3      ..    ..     ..
> 2001 Dec 30 [Sun]    324.1  -10.4    -52.3   61.1      ..    ..     ..
> 2001 Dec 31 [Mon]    322.3  -10.4    -52.7   60.6      ..    ..     ..
> 2002 Jan 01 [Tue]    320.4  -10.4    -52.9   60.4      ..    ..     ..
> 2002 Jan 02 [Wed]    318.6  -10.4    -52.8   60.4      ..    ..     ..
> 2002 Jan 03 [Thu]    315.1  -10.5    -52.3   61.2      ..    ..     ..
> 2002 Jan 04 [Fri]    313.2  -10.5    -51.8   61.9      ..    ..     ..
> 2002 Jan 05 [Sat]    311.4  -10.5    -51.1   62.8      ..    ..     ..
> 2002 Jan 06 [Sun]    309.6  -10.5    -50.2   64.0      ..    ..     ..
> 2002 Jan 07 [Mon]    306.1  -10.5    -48.4   66.4      ..    ..     ..
> 2002 Jan 08 [Tue]    304.2  -10.6    -47.2   68.0      ..    ..     ..
> 2002 Jan 09 [Wed]    302.4  -10.6    -45.8   69.7  << Sun sensor restarts
> 2002 Jan 10 [Thu]    300.5  -10.6    -44.3   71.5
> ..
> ---------------------------------------------------
>
> On Jan 09, when the Sun sensor recovers lock, the magnetorquer will be
used
> once again to:
>
>  a) counteract the "mystery effect" precession (drift) in alon
>  b) to drive alat towards alat=0
>  c) increase alon towards alon=360 as rapidly as the Sun's movement
allows.
>
> Broadly the future should be:
>
>   Date         Alon  Alat
>   -----------------------
>   2002 Jan 08   300  -10
>   2002 Jan 15   300   -5
>   2002 Jan 22   300    0
>   2002 Feb 19   320    0
>   2002 Mar 19   340    0
>   2002 Apr 13   360    0
>   -----------------------
>
> Excellent communications are available now, and will be maintained
throughout
> this period.
>
> JRM 2001 Dec 29 [Sat] 1414 utc
>
____________________________________________________________________________
__
>
> ----
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