PDS_VERSION_ID          = PDS3
RECORD_TYPE             = STREAM

OBJECT                  = TEXT
   INTERCHANGE_FORMAT   = ASCII
   PUBLICATION_DATE     = 2016-05-06
   NOTE                 = "PC-Kernel Information"
END_OBJECT              = TEXT

END


General Information About SPICE PC-Kernels
==========================================

   In the SPICE system, the PC-kernels contain planetary attitude and
   body shape information. The PCK kernel includes orientation and
   shape information pertaining to extended solar system bodies such as
   the Sun, the planets, the natural satellites of the planets, comets,
   and asteroids.

   The purpose of the PCK kernels and associated software is to provide
   SPICE users with a convenient mechanism for supplying planetary
   physical constants to application programs. SPICE's PCK software is
   able to read files conforming to the PCK format and return to a
   calling application program both the data contained in such files
   and a small number of commonly used numeric quantities derived from
   the kernel data. The information regarding how to obtain the SPICE
   system toolkit for a number of languages and computer platforms is
   located in the ``/software'' subdirectory of the main directory of
   this data set.

   Refer to the ``pck.req'' document provided with the toolkit to get
   more information on how to access PC-kernel data.


MESSENGER PC-kernels Contained in This Data Set
===============================================

   This following PC-Kernel files are provided in this data set:

   -- MESSENGER specific PCK files:

         pck000<nn>_msgr_v<vv>.tpc  the latest PCK file providing the
                              contents of the generic NAIF PCK product
                              identified with the leading pck000<nn> and
                              followed by any Mercury specific parameters
                              adopted by the project.  This includes, but
                              is not limited to, the body radii and the
                              rotational parameters defining the body
                              fixed IAU_MERCURY frame.  <nn> indicates the
                              version of the NAIF generic PCK which this 
                              file was derived, and <vv> is the version 
                              number of the product itself.


Retired Files 
=============

   As the mission progressed and the project decided to update the rotational
   parameters for the Mercury body-fixed frame, it was decided to consolidate
   the NAIF generic PCK and any changes adopted by the project into a single
   file.  This was largely done to alleviate any chance of confusion in the
   consumption of the PCK data.

   As such, the following products are now retired and their usage is 
   discouraged:

      pck00008.tpc 
      pck00008_msgr.tpc
      pck00009_msgr_v10.tpc
      pck00010.tpc
      pck00010_msgr_v10.tpc


Kernel File Details
===================

   The most detailed description of the data in a text PCK file is
   provided in metadata included inside the description area of the
   file. This information can be viewed using any text editor program.

   The most detailed description of the data in a binary PCK file is
   provided in metadata included inside the comment area of the file.
   This information can be viewed using utility programs COMMNT and
   SPACIT included into the NAIF Toolkit.


Contact Information
===================

   Regarding MESSENGER project specific information provided in this
   data set:

      Mike Reid
      (240)228-4537
      Mike.Reid@jhuapl.edu

   address:

      The Johns Hopkins University Applied Physics Laboratory
      11100 Johns Hopkins Road
      Laurel, MD 20723

   For general information about SPICE system:

      Charles H. Acton, Jr,
      (818)354-3869,
      Charles.Acton@jpl.nasa.gov,

   or

      Boris Semenov
      (818)354-8136
      Boris.Semenov@jpl.nasa.gov

   address:

      Navigation and Ancillary Information Facility (NAIF)
      Jet Propulsion Laboratory
      MS 301-121
      4800 Oak Grove Drive
      Pasadena CA 91109 USA