PDS_VERSION_ID          = PDS3
RECORD_TYPE             = STREAM

OBJECT                  = TEXT
   INTERCHANGE_FORMAT   = ASCII
   PUBLICATION_DATE     = 2011-06-23
   NOTE                 = "SP-Kernel Information"
END_OBJECT              = TEXT

END

General information about SPICE SP-kernels
==========================================

   The purpose of the SP-kernel (SPK), which stands for S(pacecraft)
   and P(lanet) Kernel, is to allow ephemerides for any collection of
   solar system bodies, spacecraft or any other objects in 3D space to
   be combined under a common file format, and accessed by a common set
   of subroutines. SP Kernels provide the state of a target relative to
   its center of motion, where ``state'' implies Cartesian position and
   velocity at a requested epoch.

   The SPK format is supported by a collection of subroutines that are
   part of the SPICELIB library, the major component of the NAIF
   Toolkit. These subroutines can be integrated into user application
   programs. Information about obtaining the SPICE Toolkit is located
   in the "software" subdirectory of the main directory of this
   dataset.

   To use SP-kernels, a Leapseconds Kernel (LSK) is required. Also, to
   use SP-Kernels containing states defined relative to non-inertial or
   project-defined frames, a Frames Kernel (FK) and/or Planetary
   Constants Kernel (PcK) are required.

   Refer to the SPK Required Reading (spk.req) document provided with
   the Toolkit or available from the NAIF Node of the PDS, to get more
   information on how to access SP-kernel data.


EPOXI SP-kernels Provided in This Data Set
==========================================

   This directory contains the SPICE SP-Kernel files for the Deep
   Impact Flyby (DIF) spacecraft, EPOXI mission targets comets Hartley
   2, and solar system bodies. All files are in IEEE big endian binary
   format and suitable for use on UNIX workstations and MACs. The
   following files are present in this directory. (Only the leading
   portions of the file names are shown; the file name extensions of
   the binary SPK files are always ".bsp"):

      dif_epoch_nav_v1       SPK file providing the reconstructed DIF
                             spacecraft trajectory for the EPOCh part
                             of the mission and predicted DIF
                             spacecraft trajectory for the DIXI part of
                             the mission as well as ephemerides of the
                             comet Hartley 2 and solar system bodies
                             for the whole duration of the mission,
                             generated at the end of the EPOCh part of
                             the mission.

      dif_dixi_nav_v1        SPK file providing the reconstructed DIF
                             spacecraft trajectory for the DIXI part of
                             the mission and predicted DIF spacecraft
                             trajectory from the end of the DIXI part
                             of the mission to 2021 as well as
                             ephemerides of the comet Hartley 2 and
                             solar system bodies for the whole duration
                             of the mission, generated at the end of
                             the DIXI part of the mission. This file
                             provides the best reconstructed trajectory
                             for Hartley 2 encounter available at the
                             end of the mission.

   To provide spacecraft and target trajectory for the whole mission 
   these two SPK files must be loaded together with the EPOCh SPK file 
   loaded first:

      dif_epoch_nav_v1.bsp
      dif_dixi_nav_v1.bsp


EPOXI SPK File Naming Scheme
==================================

   The EPOXI SPKs provided in this data set are named according to the
   following scheme:

      dif_ident_prod_vX[_modif].bsp

   where:

      ident     is a token identifying the type and coverage of
                trajectory data provided in the file. Examples:
                "epoch" -- trajectory for the EPOCh part of the mission.

      prod      is a token identifying the data producer. Examples:
                "nav" -- EPOXI Navigation team, etc.

      vX        is the file version number.

      modif     is an optional modifier indicating additional
                processing done to create the file.

   The file with the highest version number supersedes all files with
   the same name but earlier version numbers.


Kernel File Details
===================

   The most detailed description of the data in each 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
===================

   Regarding EPOXI project specific information provided in this
   data set and for general information about SPICE system:

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

   or

      Chuck Acton
      (818)-354-3869
      Chuck.Acton@jpl.nasa.gov

   address:

      Navigation and Ancillary Information Facility (NAIF)
      Jet Propulsion Laboratory
      MS 301-125L
      4800 Oak Grove Drive
      Pasadena CA 91109 USA