PDS_VERSION_ID          = PDS3
RECORD_TYPE             = STREAM

OBJECT                  = TEXT
   INTERCHANGE_FORMAT   = ASCII
   PUBLICATION_DATE     = 2012-10-30
   NOTE                 = "GRAIL C-Kernel Information"
END_OBJECT              = TEXT
                                                                     
END 


General Information About SPICE C-Kernels
=========================================

   In the SPICE system, pointing data for an instrument platform, or
   for a specific instrument, are stored C-kernels. The pointing of a
   platform or an instrument is often expressed in terms of a
   transformation matrix from some standard inertial reference frame to
   a instrument-fixed frame. In the past, the instrument was often a
   camera, and the transformation was thus dubbed the ``C-matrix'';
   hence the choice of C as the name for the pointing kernel.
 
   The CK files can be accessed and manipulated using the SPICE Toolkit
   APIs, calls to which can be integrated into user application
   programs. 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.
 
   To use C-kernels, a Spacecraft Clock Kernel (SCLK) is required.
   Also, for C-Kernels containing orientation of a project-defined
   frames, a Frame Definitions File is required.
 
   Refer to the ``ck.req'' document provided with the toolkit or
   available from the NAIF Node of PDS if SPICE toolkit is not included
   with this data set to get more information on how to access C-kernel
   data.



GRAIL C-kernels Contained in This Data Set
=========================================

   The following GRAIL C-kernels are provided in this data set (only name
   portion of the file name is shown; the extension of all file names
   is ``.bc''):

   GRAIL Spacecraft Orientation CK Files:

      SC_rec_BEG_END[_vV]      CK files providing actual telemetry
                               -based orientation of the GRAIL-A
                               (SC=gra) or GRAIL-B (SC=grb) spacecraft
                               bus for the BEG to END time period. The
                               dates are specified in the YYMMDD
                               format. The appendage [_vV], in which V
                               is the version number, is omitted for
                               version 1.


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

   The most detailed description of the data in a binary CK 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 GRAIL project specific information provided in this data set
   and for general information about SPICE system:
   
      Boris Semenov 
      (818)-354-8136 
      Boris.Semenov@jpl.nasa.gov
      
   address:
   
      Navigation and Ancillary Information Facility (NAIF)
      Jet Propulsion Laboratory
      MS 301-125L
      4800 Oak Grove Drive
      Pasadena CA 91109 USA