James Webb Space Telescope SPK files
===========================================================================

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

   It was last modified on May 12, 2020 by Marc Costa Sitja, ESAC/ESA.


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

   This directory contains the SPICE SP-Kernel files for the JWST
   mission, including mission analysis, nominal and operational spacecraft
   trajectory SPKs, generic planetary and satellite ephemeris SPKs.


Data Origin
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     Please note that the data used to generate the SPK kernels present in this
     directory has been obtained with HORIZONS.


Current SPK Kernels Set
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    jwst_horizons_YYYYMMDD_YYYYMMDD_vNN.bsp

       SPICE SPK file that contains JWST predicted orbit information.
       The file is generated by the ESA SPICE Service using data
       from the Horizons tool.

    de432s.bsp

       SPICE SPK file containing JPL planetary ephemerides version DE432,
       created by NAIF, JPL.


Other directory contents
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   aareadme.txt         This file.


Particulars
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     SPKs generated from horizons originally contain LT CORRECTED cartesian
     states. These have been considered to be GEOMETRICAL cartesian states
     for the purpose of the application this is considered to be acceptable.


Kernel File Details
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     The most detailed description of the data in a binary SPK 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 NAIF Toolkit.


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


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

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


End of aareadme file.