PDS_VERSION_ID          = PDS3
RECORD_TYPE             = STREAM

OBJECT                  = TEXT
   INTERCHANGE_FORMAT   = ASCII
   PUBLICATION_DATE     = 2019-10-02
   NOTE                 = "This file describes the files in the
                           extras/orbnum directory of this volume."
END_OBJECT              = TEXT

END


Orbit number files for the SELENE Main Orbiter
==============================================

   This directory contains the orbit number file generated during the
   SELENE (also known as Kaguya) mission using the NAIF's ORBNUM
   utility program for the main spacecraft trajectory SPK files of
   the mission. The orbit number files are named sel_main_vVV.orb,
   where VV is the version number. The file with the latest version
   supersedes all files with earlier versions. The orbit number files
   are plain ASCII text files that have lines terminated with a line
   feed character, LF (ASCII 10).

   The files included in this dataset are the most recent files
   available at the moment of the compilation of each release of this
   dataset, which should span at least the same time interval as all
   the SPK files included in the dataset.

   They contain data that follow the "periapsis-to-periapsis" orbit
   numbering scheme -- with the orbit number changing at periapsis.

   The information contained in the orbit number files includes:

    - Orbit number ("No".)
    - Ascending node UTC time ("Event UTC A-NODE")
    - SCLK time ("Event SCLK A-NODE")
    - Descending UTC time ("OP-Event UTC D-NODE")
    - Sub-solar geodetic longitude and latitude (SolLon, SolLat), in
      the MOON_ME reference frame.
    - Sub-spacecraft geodetic longitude and latitude (SC Lon, SC Lat),
      in the MOON_ME reference frame.
    - Altitude relative to the IAU 2000 Lunar ellipsoid (Alt)
    - Inclination of the vehicle orbit (Inc)
    - Eccentricity of the orbit plane about the primary body (Ecc)
    - Longitude of the ascending node of the orbit (LonNode)
    - Solar distance the time of the orbit event (Sol Dist)
    - Semimajor axis of the orbit (Semi Axis)

   All the orbital elements are calculated in the MOON_ME reference
   frame.


Important Note Regarding Orbit Number Files
===========================================

   Orbit number 1 corresponds to the first orbit, started from
   2007-10-03T02:44:01.
 
   All derived quantities provided on each record -- sub-solar lon/lat,
   sub-spacecraft lon/lat/alt, and orbital elements -- are computed for
   the time of pericenter.


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

   Regarding the SELENE Project specific information provided in this
   data set and for general information about SPICE system, contact:
 
      Yukio Yamamoto
      +81-50-3362-2612
      yukio@planeta.sci.isas.jaxa.jp
 
   , or 
 
      Boris Semenov   
      (818)-354-8136  
      Boris.Semenov@jpl.nasa.gov