Solar Orbiter MK files
===========================================================================

   This ``aareadme.txt'' file describes the contents of the kernels/mk
   directory of the Solar Orbiter SPICE Kernel Dataset.

   It was last modified on February 23, 2023 by Ricardo Valles, ESAC/ESA.


Brief Summary
------------------------------------------------------------------------

   This directory contains the SPICE Meta-Kernel files for the
   SOLAR ORBITER mission. Meta-kernels (also known as ``FURNSH kernel'')
   are a way of loading a  self-consistent dataset with a single command.
   They are essentially an ASCII file containing a list of other kernels to
   load, and are how we will manage version control: If a user has access to
   the entire Solar Orbiter SPICE Kernel Dataset and loads the most recent
   meta-kernel, they will automatically be using the most recent versions of
   each kernel.

   SOC will maintain two meta-kernels: One for the predictive dataset, and
   one for the as- flown dataset. This is necessary because of the different
   spacecraft clocks used in the production of the attitude kernels.


File naming conventions and Kernel File Details
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   The naming scheme for the SOLAR ORBITER MKs is:

      solo_ANC_soc-TYPE-mk[_VNNN_YYYYMMDD_XXX].tm

   where

         TYPE      Type of meta-kernel:

                      pred: predicted attitude
                      flown: as-flown attitude

         NNN       version number that corresponds to the version of the
                   meta-kernel or the SPICE Kernel Dataset release number
                   (optional, e.g. v121 for Release 1.2.1)

         YYYYMMDD  a date tag of the MK generation time (optional,
                   e.g. 20190604);

         XXX       a count of the MK version generated for a given date.
                   (optional, e.g. 001)


Other directory contents
------------------------------------------------------------------------

   aareadme.txt         This file.

   former_versions      Directory where old versions are stored for
                        archive and consistency purposes.


Particulars
------------------------------------------------------------------------

   Meta-Kernel file management is a critical element of any SPICE dataset.
   For ESA Missions the Meta-Kernels of the operational SPICE repositories
   are also used to control the version of the SPICE Kernel Dataset.

   For what concerns SPICE Kernel Dataset version kernels, they are
   generated when a new version of the kernel dataset is released.
   In parallel a new operational version is made available.

   In general missions in operations will have an "operational" Meta-Kernel.
   This MK will contain the latest SPICE kernels available for the mission
   including those kernels generated by the operational pipeline in a
   periodical basis (namely SPK, CK and SCLK files).
   Since the periodicity of this updates ranges from hours to weeks
   (should happen after every S/C Ground Station pass), the MK
   in the Meta-Kernel directory does not have a version number and is
   regularly overwritten. Nevertheless in order to keep traceability and
   backwards compatibility with former MKs, a duplicate of every generated
   MK is stored. This duplicated MK filename is appended with a time-tag and
   a version; if the original MK looks like:

      SOLAR-ORBITER/kernels/mk/solo_ANC_soc-pred-mk.tm

   the following duplicate is generated:

      SOLAR-ORBITER/kernels/mk/solo_ANC_soc-pred-mk_V100_20190704_001.tm

   New kernel datasets are typically released when new text kernels are
   added, updated or modified, when there is a change in the directory
   structure, etc. Superseded version kernels are moved to the
   'former_versions' directory.


Contact Information
------------------------------------------------------------------------

   If you have any questions regarding this file contact the
   ESA SPICE Service (ESS) at ESAC:

           Alfredo Escalante Lopez
           (+34) 91-8131-429
           spice@sciops.esa.int

   or the Solar Orbiter Science Operations Center at ESAC:

           sol_soc@esa.int


References and required readings
------------------------------------------------------------------------

   1. ``Kernel Required Reading'', NAIF Document

   2. ``SOC-Provided Ancillary Data for Solar Orbiter'',
      SOL-SGS-TN-0017, A. Walsh, Issue 0, Revision 3, 22/09/2018


End of aareadme file.