PDS_VERSION_ID          = PDS3
RECORD_TYPE             = STREAM

OBJECT                  = TEXT
   INTERCHANGE_FORMAT   = ASCII
   PUBLICATION_DATE     = 2010-08-30
   NOTE                 = "LRO SP-Kernel Information"
END_OBJECT              = TEXT

END

General Information About SPICE SP-Kernels
==========================================

   The purpose of the SP-kernel -- 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.

   The SPK files can be accessed and manipulated using the SPICE
   Toolkit APIs, calls to which can be integrated into user application
   programs. The information regarding how to obtain the SPICE system
   toolkit for a number of languages and computer platforms is located
   in the ``/software'' subdirectory of the main directory of this data
   set.

   To use SP-kernels, a Leapseconds (LSK) is required. Also, to use
   SP-Kernels containing positions given relative to the non-inertial
   and project-defined frames, a Frame Definitions (FK) and Planetary
   Constants (PCK) files are required.

   Refer to the ``spk.req'' document provided with the toolkit to get
   more information on how to access SP-kernel data.


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

   This directory contains the SPICE SP-kernel files for the LRO
   mission. All files are in IEEE big endian binary format.

   The following SPK files are provided in this directory (only the
   leading portion of the file name is shown; the extension of all SPK
   file names is ``.bsp''):

      lrorg_YYYYDOY_yyyydoy_v??    merged reconstructed spacecraft
                                   ephemeris SPK files, created by
                                   merging together ``as is'' sets
                                   daily LRO definitive spacecraft
                                   ephemeris SPK files
                                   (fdf29_???????_???????_???.bsp)
                                   produced by the LRO project during
                                   operations. YYYYDOY and yyyydoy in
                                   the file name identify the period
                                   covered by the file; NN identifies
                                   the file version.

      lrorp_YYYYDOY_yyyydoy_v??    merged reconstructed reprocessed
                                   spacecraft ephemeris SPK files,
                                   created by merging together ``as
                                   is'' sets LRO reprocessed spacecraft
                                   ephemeris SPK files
                                   (fdf36_???????_???????_???.bsp)
                                   produced by the LRO project during
                                   operations. YYYYDOY and yyyydoy in
                                   the file name identify the period
                                   covered by the file; NN identifies
                                   the file version.

      de421                        DE421 planetary ephemeris SPK file
                                   containing ephemeris data for the
                                   Solar System planet barycenters,
                                   Sun, Mercury, Venus, Earth, Moon,
                                   and Lunar.

   If more than one SPK covering the same period of time is present in
   either of the two LRO spacecraft SPK sets, the SPK with the latest
   version supersedes all SPKs with earlier versions.

   If available for the interval of interest, the merged reconstructed
   reprocessed spacecraft ephemeris SPK files supersede the merged
   reconstructed spacecraft ephemeris SPK files.


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 utility programs COMMNT and
   SPACIT included into the NAIF Toolkit.


Contact Information
===================

   Regarding Lunar Reconnaissance Orbiter project specific information
   provided in this data set contact:

      Rick Saylor
      (301)-614-1354
      Richard.S.Saylor@nasa.gov

   address:

      NASA Goddard Space Flight Center (GSFC)
      Mail Stop 451.0
      Building 12 Room N233
      Greenbelt MD 20771