KPL/PCK

Comet Churyumov-Gerasimenko -- RSOC Solution
===========================================================================

 
Version and Date
--------------------------------------------------------

     Version 0.3 -- June 14, 2012 -- J. Vazquez, SRE-OSR/ESA
                    BODY1000012_LONG_AXIS keyword (deprecated) removed.

     Version 0.2 -- June 4, 2012 -- B. Grieger, SRE-OSR/ESA
     
     Version 0.1 -- January 26, 2011 -- M. Kueppers, SRE-OSR/ESA 
                    Corrected spin axis direction.

     Version 0.0 -- September 9, 2010 -- J. Vazquez, PSA, SRE-OS/ESA
     
 
 
Organization
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     The sections of this file are as follows.
 
     Introductory Information:
 
         --   Version description
 
         --   Disclaimer
 
         --   Sources
 
     Pck Data:
 
         --   Orientation constants for Comet 67P/Churyumov-Gerasimenko
 
         --   Radii for Comet 67P/Churyumov-Gerasimenko
 
 
Version description
--------------------------------------------------------
 
     This is a PCK containing values for the pole orientation, 
     rotation period and shape obtained from [2] and [3].
     
 
Disclaimer
--------------------------------------------------------
 
     This constants file may not contain the parameter values that you
     prefer. Note that this file may be readily modified by you or
     anyone else. PSA suggests that you inspect this file visually
     before proceeding with any critical or extended data processing.
 
     PSA requests that you update the version section if you modify
     the file.
 
 
Sources
--------------------------------------------------------
 
     The sources for the constants listed in this file are:
 
        1) ESA Science and Technology Server, Rosetta area,
           http://sci.esa.int/science-e/www/object/index.cfm?
           fobjectid=34849

        2) Technical note RO-ESC-TN-5566

Orientation constants for Comet Churyumov-Gerasimenko.
------------------------------------------------------

     The direction of the rotation axis and the rotation period are based on
     as of 2012-Mar-30.

     The phase of the rotation is chosen so that at the reference time
     2014-08-07T12:00:00 TDB the axis of the rotation from J2000 to the comet
     fixed frame is prependicular to the z-axis.

     \begindata
 
        BODY1000012_POLE_RA       = (  220.0            0.0            0.0 )
        BODY1000012_POLE_DEC      = (  -70.0            0.0            0.0 )
        BODY1000012_PM            = (  -86.369364827  679.245283019    0.0 )
 
     \begintext

     An ellipsoid of the same volume as the polyhedron shape model was fitted
     to the shape model. The optimisation criterion was maximum common volume. 
     The smallest radius of the ellipsoid was restricted to be along the 
     z-axis.

     \begindata

        BODY1000012_RADII         = (    2.398          1.887          1.532 )

     \begintext

     Please note that the prime meridian of the comet is rotated 22.39 degrees
     east from the long axis (X) of the reference frame.

     In order to use the ellipsoid shape model with correct orientation
     relative to the polyhedron shape model, an auxiliary frame with
     appropriate rotation relative to the body fixed frame is needed. Such
     a frame named 67P/C-G_ELLIPSOID is provided in the kernel ROS_CGS_AUX_V01.TF.
     E.g., in calls to SINCPT, the name 67P/C-G_ELLIPSOID has to be passed
     as body-fixed, body-centered target body frame.