PDS_VERSION_ID          = PDS3
RECORD_TYPE             = STREAM

OBJECT                  = TEXT
   INTERCHANGE_FORMAT   = ASCII
   PUBLICATION_DATE     = 2017-07-01
   NOTE                 = "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 as C-kernels (CK).  The
   pointing of a platform or an instrument is often expressed in terms
   of a transformation matrix from some standard base 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 data contained in C-kernel files can be accessed and manipulated
   by a collection of subroutines that are part of the SPICELIB
   library, the major component of the SPICE Toolkit. These subroutines
   can be integrated into user application programs. Information about
   obtaining the SPICE Toolkit is located in the ``software''
   subdirectory of the main directory of this dataset.

   To use C-kernels, a Spacecraft Clock Kernel (SCLK) is required.
   Also, for C-Kernels containing orientation of project-defined
   frames, a Frame Kernel file is required.

   Refer to the CK Required Reading (ck.req) document provided with the
   Toolkit or available from the NAIF Node of the PDS, to get more
   information on how to access C-kernel data.


Venus Climate Orbiter C-kernels Contained in This Data Set
==========================================================

   This directory contains the SPICE C-kernel files for the Venus
   Climate Orbiter (VCO, also known as PLANET-C and AKATSUKI) mission.
   All files are in IEEE little endian binary format.

   The following CK files are provided in this directory (only the
   leading portion of the file name is shown; the extension of all CK
   file names is ``.bc''):

      vco_YYYY_vVV          CK files containing reconstructed Venus
                            Climate Orbiter spacecraft orientation,
                            created during operations by the PLANET-C
                            Project Team. YYYY in the file name that
                            represents the year identify the period
                            covered by the file and VV is the version
                            number.

      vco_YYYY_pred_vVV     CK files containing predicted orientation
                            of the Venus Climate Orbiter spacecraft,
                            covering only ``gaps'', i.e., periods
                            without data in the yearly reconstructed CK
                            files, vco_YYYY_vVV, created by the
                            PLANET-C Project Team. YYYY in the file
                            name that represents the year identify the
                            period covered by the file and VV is the
                            version number. For the case of YYYY with
                            2012 and 2013, there aren't any gaps in the
                            reconstructed CKs, so the predicted CKs for
                            2012 and 2013 don't exist.

      vco_sap_nominal_vVV   CK files containing two Solar Array
                            Paddles' orientation of the Venus Climate
                            Orbiter spacecraft, with respect to the
                            dynamic frame named ``VCO_SAP_NOMINAL''.
                            Team. VV in the file name is the version
                            number.

      vco_sap_YYYY_vVV      CK files containing two Solar Array
                            Paddles' orientation of the Venus Climate
                            Orbiter spacecraft, with respect to the
                            Venus Climate Orbiter spacecraft body-fixed
                            frame, created by the PLANET-C Project
                            Team. YYYY in the file name that represents
                            the year identify the period covered by the
                            file and VV is the version number.

      vco_xmga_YYYY_vVV     CK files containing two X-band Medium Gain
                            Antennas' orientation of the Venus Climate
                            Orbiter spacecraft, with respect to the
                            Venus Climate Orbiter spacecraft body-fixed
                            frame, created by the PLANET-C Project
                            Team. YYYY in the file name that represents
                            the year identify the period covered by the
                            file and VV is the version number.

   If this data set contains multiple CK files for a particular period,
   the one with the latest version (VV) supersedes all previous versions.

   In most cases these CK files

      vco_YYYY_pred_vVV.bc
      vco_YYYY_vVV.bc
      vco_sap_nominal_vVV.bc
      vco_sap_YYYY_vVV.bc
      vco_xmga_YYYY_vVV.bc

   should be loaded in this order into a user's application to process
   data for the mission.


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 the utility programs COMMNT and
   SPACIT included in the SPICE Toolkit. The Toolkit is available from
   the NAIF website.