ROSAT Status Report #134

[THE RAGE OF CALIBAN <TURNER@LHEAVX.GSFC.NASA.GOV>]

           		ROSAT Status Report #134

   			    Dec 21 1995


=========================================================================
=                                                                       =
=              ROSAT NEWS No. 43   ---      21-Dec-1995                 =
=                                                                       =
=-----------------------------------------------------------------------=
=                 ROSAT Scientific Data Center at the                   =
=       Max-Planck-Institut fuer Extraterrestrische Physik (MPE)        =
=               Postfach 1603, D-85740 Garching, Germany                =
=-----------------------------------------------------------------------=
=  e-mail addresses (Uli Zimmermann):                                   =
=   rosat_svc@mpe-garching.mpg.de (Internet) or  MPE::ROSAT_SVC (SPAN)  =
=  ROSAT Service Area (including ROSAT Data Archive):                   =
=   ftp rosat_svc.mpe-garching.mpg.de      user: anonymous              =
=   WWW address:  http://rosat_svc.mpe-garching.mpg.de/                 =
=   interactive account (including ROSAT Result Archive):               =
=     telnet xray.mpe-garching.mpg.de  user: xray  no password          =
=-----------------------------------------------------------------------=
=  XUV Center: 29382::GXUVDC or  GXUVDC@AIT.PHYSIK.UNI-TUEBINGEN.DE     =
=   WFC Archive access via telnet/ftp ait.physik.uni-tuebingen.de       =
=                                user: xuv  (password: xuv_archive)     =
=   WWW address:  http://astro.uni-tuebingen.de/rosat.html              =
=========================================================================


              the team of the ROSAT Data Center wishes you

                                                                                
             |        M E R R Y   C H R I S T M A S        |                  
            - -                                           - -                 
            / \                                           / \                 
           /o *\                 and  a                  /* o\                
          /_   _o                                       /_   _\               
           o * \                                         * o \                
          /   o \         S U C C E S S F U L L         /   * \               
         /_*    _\                                     /_o    _\              
          /o   *\                                       /*   o\               
         /    o  \          Y E A R   1 9 9 6          /    *  \              
        /__*_ __o_\                                   /__o_ __*_\             
            | |                                           | |                 
  __________| |___________________________________________| |__________
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Contents:  SATELLITE STATUS
           EXSAS


SATELLITE STATUS
================
On December 2nd ROSAT entered the safemode from which it was recovered 
after about 8 hours. It was the first genuine AMCS safe mode since 
October 29, 1994. An unsuccessful target acquisition attempt occured 
before entry of the spacecraft into the shadow phase of the orbit. 
As is usual in this situation, the satellite was angular momentum 
stabilized and began a precession movement. The sunlit phase of the orbit 
was then entered with a sun angle greater 15 deg. In such a situation
there is a margin of 5 min for AMCS software to re-acquire a sun angle 
below 15 deg. The AMCS just fell short of achieving this within the 5 min 
so that the AMCS safemode was triggered. Obviously, this event was just 
an extreme in a distribution of similar events that for the most part 
are routinely handled with success. Recovery from the safemode was 
straightforward. The general performance of the AMCS has been very 
stable.

EXSAS
=====
A new version of EXSAS, compatible with the November95 version of MIDAS,
is in preparation and will be available in the second half of January.

====================== end of ROSAT NEWS ================================