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Re: AO-40 Attitude Information




Hi Norbert,


The transponder will be on, but will only be useful from MA 10 to MA 35 or so.
The poor squint angle (no better than 15-20 deg) will be partly compensated
by the reduced range, though.  So you may try, but conditions might not be
too good due to the spacecraft attitude.

73s Peter DB2OS



Norbert Sayou wrote:
> 
> 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
> >
> ____________________________________________________________________________
> __
> >
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> 
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
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