
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.

   CKs can be accessed by subroutines that are part of the SPICE
   library, the major component of the SPICE Toolkit. These subroutines
   can be integrated into user application programs. For information on
   the SPICE Toolkit and/or how to obtain it, please consult
   SPICE_INST.CAT and SOFT.CAT.

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

   Refer to the CK.REQ and FRAMES.REQ documents provided with the
   Toolkit or available from the NAIF Node of PDS to get more
   information on how to access C-kernel data.


ROSETTA C-Kernel Files
======================

   This file describes the contents of the DATA/CK directory of the
   ROSETTA SPICE data set.

   The contents and time span covered by any CK file may be easily
   determined using the 'ckbrief' utility program available in all
   copies of the SPICE Toolkit. Example:

      %ckbrief <ck_file_name> <sclk_file_name> <lsk_file_name>

   This utility requires additionally a SCLK file and an LSK file; use
   the latest versions of these files.

   Descriptive information about how/why/when a CK file was created is
   usually available in the 'comment area' of the file. This may be
   viewed using the 'commnt' utility program available in all the SPICE
   Toolkit. Use the '-r' option to read the comments. Example:

     %commnt -r <ck_file_name>

   All binary CK files (*.BC) contained in this directory are
   little-endian (LTL-IEEE) binary files.


Rosetta C-kernels contained in this data set
============================================

   The following ROSETTA C-kernels are provided in this data set:

   Rosetta Orbiter Orientation CKs:

      RATT_DV_145_01_01____00216.BC
      RATT_DV_223_01_01____00302.BC 
      RATT_DV_257_02_01____00344.BC 
      RATT_DV_145_01_01_T6_00216.BC 
      RATT_DV_223_01_01_T6_00302.BC 
      RATT_DV_257_02_01_T6_00344.BC   Contains the orientation of the
                                      Rosetta orbiter frame
                                      ('ROS_SPACECRAFT') during orbital
                                      operations, based on data provided
                                      by ESOC.

      ATNR_P040302093352_00046.BC
      ATNR_P040302093352_00096.BC
      ATNR_P040302093352_00109.BC
      ATNR_P040302093352_00127.BC
      ATNR_P040302093352_T6_00127.BC  Contain the orientation of the
                                      Rosetta orbiter frame
                                      ('ROS_SPACECRAFT'), covering from
                                      launch to the comet rendezvous
                                      maneuver, based on data provided
                                      by ESOC. The file with the latest
                                      version supersedes all previous
                                      versions.

      ROS_ORBITER_EXTENSION_V2.BC     Contains the orientation of the
                                      Rosetta orbiter frame
                                      ('ROS_SPACECRAFT') after end of
                                      mission with a constant attitude
                                      defined by the last datapoint of
                                      RATT_DV_257_02_01_T6_00344.BC.

      ROS_SC_MES_050501_060101_V03.BC
      ROS_SC_MES_060101_070101_V03.BC
      ROS_SC_MES_070101_080101_V03.BC
      ROS_SC_MES_080101_090101_V03.BC
      ROS_SC_MES_090101_100101_V03.BC
      ROS_SC_MES_100101_110101_V03.BC
      ROS_SC_MES_110101_110608_V03.BC
      ROS_SC_MES_140120_150101_V03.BC
      ROS_SC_MES_150101_160101_V03.BC
      ROS_SC_MES_160101_160930_V03.BC Contain the "measured" orientation of
                                      the Rosetta orbiter frame
                                      ('ROS_SPACECRAFT') obtained from
                                      Housekeeping Telemetry.

      ROS_SC_DLR_S4S_1408_1409_V1.BC  This CK contains 251 Type 3 CK segments
                                      each covering a two-second interval
                                      corresponding to one of OSIRIS images
                                      taken in August-September 2014 and used
                                      in producing the SHAP4S shape model.

      ROS_SC_REC_140801_141231_V01.BC
      ROS_SC_REC_150101_151231_V01.BC
      ROS_SC_REC_160101_160601_V01.BC Contains Rosetta reconstructed attitude
                                      information. This attitude has been
                                      reconstruced by Bjoern Grieger using
                                      OSIRIS and NAVCAM images of the comet
                                      nucleus. Note that these CKs show a
                                      discrepancy of around 5 mdeg during
                                      slews with respect to the predicted
                                      CKs from Flight Dynamics.

   Rosetta Lander Orientation CKs:

      LATT_ROS2LDR_PRESEP_V1_0.BC     Contains Rosetta Lander orientation
                                      before the Lander separation from the
                                      Rosetta Orbiter. The Rosetta Lander is
                                      attached to the Rosetta Orbiter.

      LATT_CFF2LDR_FSS_V2_0.BC        Contains Rosetta Lander attitude for the
                                      First Science Sequence and beyond
                                      (until EOM). The data was provided by
                                      SONC-FD.

      LATT_EME2LDR_SDL_V1_0.BC        Contains Rosetta Lander attitude for the
                                      Separation, Descent and First Landing as
                                      defined by the data was by SONC-FD.

      LATT_ROS2LDR_SDL_ROMAP_V1_0.BC  Contains Rosetta Lander attitude for the
                                      Separation, Descent and First Landing as
                                      defined by the data was by ROMAP.

   Comet 67P/C-G Orientation CKs:

      CATT_DV_145_01_______00216.BC
      CATT_DV_145_02_______00216.BC
      CATT_DV_223_02_______00302.BC
      CATT_DV_257_03_______00344.BC  Contains the orientation of the
                                     comet 67P/C-G body-fixed frame
                                     ('67P/C-G_CK'), based on data
                                     provided by ESOC.

   VIRTIS-M Orientation CKs:

      ROS_VIRTIS_M_0403_1509_V1.BC
      ROS_VIRTIS_M_1509_1609_V1.BC   Contains the actual orientation of
                                     the VIRTIS-M articulating frame
                                     ('ROS_VIRTIS-M_SCAN'), created by
                                     merging individual CKs produced by
                                     the VIRTIS team.

      ROS_VIRTIS_ZERO_V1.BC          Contains the fictitious
                                     orientation of the VIRTIS-M
                                     articulating frame
                                     ('ROS_VIRTIS-M_SCAN') at "zero"
                                     position. This can be used only
                                     for applications for which assuming
                                     that VIRTIS-M mirror was at zero
                                     position is acceptable.


   High Gain Antenna Orientation CKs:

      ROS_HGA_2004_V0001.BC
      ROS_HGA_2005_V0001.BC
      ROS_HGA_2006_V0001.BC
      ROS_HGA_2007_V0001.BC
      ROS_HGA_2008_V0018.BC
      ROS_HGA_2008_V0019.BC
      ROS_HGA_2009_V0051.BC
      ROS_HGA_2009_V0052.BC
      ROS_HGA_2010_V0042.BC
      ROS_HGA_2010_V0046.BC
      ROS_HGA_2011_V0018.BC
      ROS_HGA_2014_V0044.BC
      ROS_HGA_2015_V0038.BC
      ROS_HGA_2015_V0053.BC 
      ROS_HGA_2016_V0042.BC          Contain the orientation of the
                                     Rosetta High Gain Antenna frames
                                     ('ROS_HGA_EL' and 'ROS_HGA_AZ'),
                                     in yearly chunks. For each year,
                                     the file with the latest version
                                     supersedes all files with earlier
                                     versions.


   Solar Array Orientation CKs:

      ROS_SA_2004_V0001.BC
      ROS_SA_2005_V0001.BC
      ROS_SA_2006_V0001.BC
      ROS_SA_2007_V0001.BC
      ROS_SA_2008_V0038.BC
      ROS_SA_2009_V0054.BC
      ROS_SA_2010_V0043.BC
      ROS_SA_2010_V0052.BC
      ROS_SA_2011_V0020.BC
      ROS_SA_2014_V0047.BC
      ROS_SA_2015_V0037.BC 
      ROS_SA_2015_V0042.BC 
      ROS_SA_2016_V0041.BC           Contain the orientation of the
                                     Rosetta Solar Arrays frames
                                     ('ROS_SA+Y' and 'ROS_SA-Y'), in
                                     yearly chunks. For each year, the
                                     file with the latest version
                                     supersedes all files with earlier
                                     versions.


   RPC Boom 2 Orientation CKs:

      ROS_LBOOM_V0.BC                Contain the orientation of the
                                     RPC boom 2 frame ('ROS_RPC_BOOM2').


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 SPICE Toolkit.

   At least a basic knowledge of the SPICE system is needed in order to
   use these kernels. The SPICE Toolkit provides versions in Fortran
   (SPICELIB), C (CSPICE), IDL (Icy), Matlab (Mice), and Java
   (JNISpice) and the user can choose any one that suits him/her.

   The SPICE routine FURNSH can be used to load a kernel file into a
   SPICE-based application to make kernel data usable with SPICE
   APIs.

   In the case when two or more binary CK files contain data
   overlapping in time for a given object the file loaded last takes
   precedence.

   Please note that CKs that contain 'T6' in their filename indicate
   that they are Type 6 CKs as opposed to type 5. T6 CKs contain
   the same data as their non-T6 counterparts but they have precedence
   due to computational efficiency (although they require Toolkit version
   N0065 or higher).
