Geometry Files

in the Mars Global Surveyor 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's trajectory and instrumentation. These include 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
ORBFACTS.TAB	An ASCII file with column headers, summarizing orbit information: orbit number, periapsis data (time, spacecraft clock, lat. & lon. of spacecraft and Sun, altitude, Mars-Sun distance), and apoapsis time.
MAG_ER.TI	A SPICE MAG/ER instrument kernel containing a MAG/ER instrument mounting description.
PCK.TPC	A "planetary constants" kernel, used by NAIF subroutines which require properties of planets and other bodies.
MO_MAGS.KER	A magnetometer constants file used for conversion of telemetry.
MO_OBJ.KER	A file which provides information about program variables used in preparation of the data.
SCLK.KER	A spacecraft clock kernel, needed to convert spacecraft ticks to Universal Time.
LEAP.KER	A leapseconds kernel file, also needed to convert spacecraft ticks to Universal Time.
HGA.TF	A frames kernel file, containing frame definitions for MGS antennas.
SC_MOD.KER	A Spacecraft Magnetic Field Model File.
MGS_ER_1.JPG	An image file showing the ER instrument geometry.
MGS_ER_2.JPG	An image file showing the ER instrument geometry.

Additional spacecraft ephemeris data are contained in the Magnetometer data.

The NAIF node of the Planetary Data System (PDS) maintains an archive of SPICE kernel files, which contain ancillary geometry data for planetary missions. NAIF also maintains software for the utilization of SPICE data. For further information on NAIF and SPICE data, consult the NAIF Website at http://pds.jpl.nasa.gov/naif.html.