NSSDCA ID: PSPG-00798
Availability: Archived at NSSDC, accessible from elsewhere
This description was generated automatically using input from the Planetary Data System.
Data Set Overview ================= The Mars Global Surveyor spacecraft includes a laser altimeter instrument. The primary objective of the Mars Orbiter Laser Altimeter (MOLA) is to determine globally the topography of Mars at a level suitable for addressing problems in geology and geophysics.
This file contains coefficients and related data for a spherical harmonic model of the shape of Mars. Input data are from the Mars Orbiter Laser Altimeter (MOLA) on the Mars Global Surveyor (MGS) spacecraft. Coordinate system is IAU 1991 (Davies et al., Celestial Mechanics and Dynamical Astronomy, 53, 377-397, 1992), areocentric, with longitudes measured positive east. When evaluated, the model gives absolute radius from Mars center of mass in meters. The model is a numerical transform of planetary radius values from the MOLA 0.5-degree gridded data set DATA_SET_ID = 'MGS-M-MOLA-5-IEGDR-L3-V2.0' PRODUCT_ID = 'MOLA-IEG0062R.IMG' into spherical harmonics using Simpson's Rule quadrature. The gridded data set included all MOLA nadir observations from the Orbit Insertion phase, plus Mapping Phase nadir observations from the beginning of mapping through the end of December 1999. Additionally, off-nadir observations of the north pole were included from 87 N latitude and northward, taken during the spring of 1998, and of both poles taken in July of 1999, from 87 N and S to the poles. Orbits 355 and 358 of the Orbit Insertion Phase and parts of orbits 10709 through 10716, inclusive, of the Mapping Phase were excluded because solutions for these orbits were deemed to be poor. (Note: subtract 10000 from a MOLA mapping phase orbit number to determine the equivalent MGS Project orbit number.) Also excluded were shots more than 1 degree off-nadir except as noted above), channel 4 returns, and any returns not classified as ground returns, e.g. clouds or noise, according to the SHOT_CLASSIFICATION_CODE. A total of approximately 123 million observations are represented. Further improvements to the model are expected as additional MGS data are incorporated. This product is a set of two ASCII tables: a header table and a coefficients table. Definitions of the tables follow. This Mars topography model was produced under the direction of D.E. Smith of the MGS MOLA Team.
These data are available on-line from the Planetary Data System (PDS) at:
http://pds-geosciences.wustl.edu/GEO/mgs-m-mola-5-shadr-v1/mgsl_2xxx/
Questions and comments about this data collection can be directed to: Dr. David R. Williams
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. David E. Smith | Data Provider | NASA Goddard Space Flight Center | david.e.smith@nasa.gov |
Dr. David E. Smith | General Contact | NASA Goddard Space Flight Center | david.e.smith@nasa.gov |