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

   It was last modified on July 30, 2020 by Marc Costa Sitja, ESAC/ESA.

   DISCLAIMER: Not all SPKs provided in this directory are described.
   This is due to the fact that the information is not available to the
   ESA SPICE Service.


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


File naming conventions
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   There is no agreed naming Scheme for Hera spacecraft SPKs.


Current SPK Kernels Set
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   HERA_sc_DESCR.bsp

      SPICE SPK file that contains Hera spacecraft trajectory covering from
      launch to arrival to Didymos for the following scenario. Where DESCR:

       LPC_EMA_2024c:   LPO and LPC of 2024 Earth-Mars-Didymos transfer with
                        constraints on departure Vinf <= 5.1 km/s and arrival
                        no later than 2026/12/28. Launch period has been
                        shortened to 18 days in order to keep total
                        Delta-V < 1100 m/s.

       LPC_EEA_2025a64: LPO and LPC of 2025 Earth-Earth-Didymos transfer with
                        constraints on departure Vinf <= 6.0 km/s, departure
                        declination fixed to 18 deg and arrival no later than
                        2031/01/31. a64 stands for Arianne 64.

       LPO_EA_2026a64:  LPO and LPC of 2026 Earth-Didymos transfer with
                        constraints on departure Vinf <= 6.0 km/s and
                        arrival no later than 2031/01/31. a64 stands for
                        Arianne 64.

       PO:              Proximity Operations based on the trajectories reported
                        on RD27.


      Created by the GMV.


   de432s.bsp

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


   estrack_vNN.bsp

      SPICE SPK file that defines the position for each of the ESA ESTRACK
      ground stations, as seen from the center of the Earth, in the
      topocentric frame defined in the corresponding ESTRACK FK.


   hera_sci_vNN.bsp

      SPICE SPK file that defines the position of some relevant points
      for science purposes.


Other directory contents
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   aareadme.txt         This file.

   coverage.txt         File that contains a summary of the coverage
                        of all the SPK files present in the directory.


Particulars
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   Trajectory data is consistent with planetary ephemeris DE-432 and with
   the leapseconds kernel naif0010.tls

   The detailed manoeuvre sequence for arrival to Didymos is not modelled
   in the provided orbit files. An operationally robust arrival sequence
   implies a delay of about 1-2 months of the arrival date.


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
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     If you have any questions regarding this directory or its
     contents, please contact SPICE support at ESAC:

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

     or NAIF at JPL:

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


References and required readings
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     1. ``SPK Required Reading'', NAIF Document


End of aareadme file.