PDS_VERSION_ID          = PDS3
RECORD_TYPE             = STREAM

OBJECT                  = TEXT
   INTERCHANGE_FORMAT   = ASCII
   PUBLICATION_DATE     = 2010-06-18
   NOTE                 = "This file describes the files in the
                           extras/orbnum directory of this volume."
END_OBJECT              = TEXT

END


Orbit Number Files for the Lunar Reconnaissance Orbiter Mission
===============================================================

   This directory contains the orbit number files generated at the
   archive preparation time using the NAIF's ORBNUM utility program
   with the spacecraft trajectory SPK files.

   The orbit number files are plain ASCII text files that have lines
   terminated with a line feed character, LF (ASCII 10).

   The orbit number files with the ``.nrb'' extension contain data that
   follow the ``node-to-node'' orbit numbering scheme -- with the orbit
   number changing at the ascending node.

   The information contained in the orbit number files includes the
   orbit number (``No.''), ascending node UTC time (``Event UTC
   A-NODE'') and SCLK time (``Event SCLK A-NODE'' ), descending UTC time
   (``OP-Event UTC D-NODE''). It also includes a few additional items
   computed at the time of ascending node such as planetocentric
   subsolar longitude and latitude (``SolLon'' and ``SolLat'') and
   planetocentric subspacecraft longitude and latitude (``SC Lon'' and
   ``SC Lat'') in the Lunar Mean Earth/Polar Axis (ME) reference frame
   based on the DE421 Lunar rotation model, spacecraft altitude above
   Lunar (``Alt'') relative to the IAU 2000 Lunar ellipsoid, and
   Sun-Lunar distance (``Sol Dist'').


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