ExoMars2016 MK files
===========================================================================

     This ``aareadme.txt'' file describes the contents of the kernels/mk
     directory of the ExoMars2016 SPICE Kernel Dataset.

     It was last modified on July 15, 2019 by Marc Costa Sitja, ESAC/ESA.


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

     This directory contains the SPICE Meta-Kernel files for the ExoMars
     2016 mission. Meta-kernels (also known as ``FURNSH kernel'') are used
     to name a collection of kernels that are to be loaded into a user's
     application at run-time. Meta-kernels are appropriate to group kernels
     that correspond to a certain study group, phase or kernel state of the
     mission.


File naming conventions
--------------------------------------------------------

   Naming Scheme for ExoMars 2016 spacecraft MKs:

     The naming scheme for the ExoMars 2016 spacecraft MKs is:

           em16[_DESC][_vXXX][_TAG][_NNN].tm

     where

           DESC      a brief description of the scope of study of the
                     scenario (optional);

           vXXX      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)

           TAG       a time tag of the MK generation time (optional;
                     e.g. 20160928);

           NNN       a count of the MK version generated for a given TAG
                     (mandatory if TAG is included; e.g 001)



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

     aareadme.txt         This file.

     former_versions      Directory where versions no longer valid are
                          stored for archive purposes.


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

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

     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 SCKL files). This MK should be used
     for Data Analysis or exceptionally Very Short Term Planning (VSTP).
     Since the periodicity of this updates ranges from hours to weeks, 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
     operational MK is stored. This duplicated MK filename is appended with a
     time tag and a version; if the original MK looks like:

        ftp/data/SPICE/ExoMars2016/kernels/mk/em16_ops.tm

     the following duplicate is generated:

        ftp/data/SPICE/ExoMars2016/kernels/mk/em16_ops_v111_20160928_001.tm

     Please note that in order to conduct Long, Mid and Short Term planning
     (LTP/MTP/STP) users should use the planning meta-kernel. This meta-kernel
     does not contain the OEMS orbit files and SATS attitude files delivered
     by FDy nor the measured CKs. The release schema is analogue to the one
     for the operational meta-kernel.

     For what concerns 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.

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


Kernel File Details
--------------------------------------------------------

    Name                            Comments
    ---------------------------------------------------------------------

    em16_ops.tm                     Contains the latest available operational
                                    kernels generated by the SPICE operational
                                    pipeline.

    em16_ops_vXXX_YYYYMMDD_NNN.tm   Is a duplicate of the operational MK that
                                    derived from release vXXX. If multiple
                                    operational MK files are generated on the
                                    same date the version NNN is increased
                                    starting from 001. Read the
                                    ``Particulars'' section for more
                                    information.

    em16_plan.tm                    Contains the long, mid and short term
                                    operational kernels generated by the SPICE
                                    operational pipeline.

    em16_plan_vXXX_YYYYMMDD_NNN.tm  Is a duplicate of the planning MK that
                                    derived from release vXXX. If multiple
                                    operational MK files are generated on the
                                    same date the version NNN is increased
                                    starting from 001. Read the
                                    ``Particulars'' section for more
                                    information.


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

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

           Marc Costa Sitja
           (+34) 91-8131-457
           esa_spice@sciops.esa.int, marc.costa@esa.int

     or SPICE support at IKI:

             Alexander Abbakumov
             +7 (495) 333-40-13
             aabbakumov@romance.iki.rssi.ru

   or NAIF at JPL:

           Boris Semenov
           +1 (818) 354-8136
           Boris.Semenov@jpl.nasa.gov



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

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


End of aareadme file.