Geometry Files

in the Lunar Prospector MAG/ER Level 1 Archive

Overview

In addition to the Magnetometer/Electron Reflectometer (MAG/ER) datasets, this disk contains ancillary data files describing the spacecraft attitude, ephemeris, position, and Sun pulse information. It also contains kernel files which can be used in the processing and interpretation of geometry data.

Links to Geometry Files

Geometry data reside in the GEOMETRY directory and its subdirectories. The principal files in the GEOMETRY directory are:

File	Description
ATTITUDE.TAB	A table of spacecraft attitude versus time. Has columns for start time, spin rate, right ascension, and declination. (This is a Level 0 file.)
LEAP_SEC.TLS	A SPICE kernel containing leapsecond data in transfer format.
LP_EPHEM.TSP	A SPICE spacecraft/planetary ephemeris kernel that contains ephemerides for the Earth, Moon, and Sun.
MOON_POS.TAB	A table of positions of the Moon relative to the Earth. Shows time; GSE coordinates of Moon (X, Y, Z, lon); and GSM coordinates of Moon (Y, Z).
GEOMINFO.TXT	A text file describing the files in the GEOMETRY directory.

The SPICE kernels are provided on this product for completeness and are not official NAIF data sets. The kernels represent the best data available from NAIF at the time of the creation of this product; however, each of these kernels is dynamic and is subject to updates with time. The official archive of all SPICE products is maintained by the Navigation and Ancillary Information Facility (NAIF) at the Jet Propulsion Laboratory (JPL) in Pasadena, CA.

In addition to being the PDS archive site for the SPICE kernels, NAIF provides and maintains a software toolkit (SPICELIB) for accessing the kernels. For more information about NAIF or SPICELIB please visit the NAIF website (http://pds.jpl.nasa.gov/naif.html).

Note that LP_EPHEM.TSP can be used to generate LP trajectory data in alternative coordinate systems and to generate transformation matrices that can rotate the magnetometer data into these systems.

The following PDS labels describe these files:

File	Description
ATTITUDE.LBL	Detached PDS label for ATTITUDE.TAB. (This is a Level 0 file.)
LEAP_SEC.LBL	Detached PDS label for LEAP_SEC.TLS.
LP_EPHEM.LBL	Detached PDS label for LP_EPHEM.TSP.
MOON_POS.LBL	Detached PDS label for MOON_POS.TAB.

The subdirectories of GEOMETRY contain still other geometry files. These subdirectories are:

Directory	Description
EME50	Contains spacecraft ephemeris data files and their detached PDS labels. (These are Level 0 files.)
TRAJECT	Contains spacecraft position files and their detached PDS labels. The position files are derived from data in the Level 0 position dataset.
SUNPULSE	Contains binary format sunpulse files and their detached PDS labels, in one-month subdirectories. (These are Level 0 files.) Filenames are Syydddhh.B (yy = year, ddd = day of year, hh = starting hour).