Exploring the Geology of Mars using Mars Orbiter Laser Altimeter (MOLA) DataAccess the MOLA Homepage , the MOLA Science Investigation homepage, and MOLA Data.
The Mars Orbital Laser Altimeter (MOLA) data set consists of two years of altimetry data on surface features on Mars. MOLA data sets are produced by the MOLA Science Team and archived by the Planetary Data Systems (more info) (PDS) Geosciences Node.
Use and Relevance
More detailed information on important discoveries stemming from MOLA data is available.
Use in Teaching
- Elevation and shape features of Mars
- Mars topography
- Methodology of laser altimetry
- Seasonal changes in snow cover on Mars
- Structural evidence of water flow on Mars
- Cloud coverage of Mars
- Interpreting topographic maps
- Using tools to generate and manipulate topographic maps
- Understanding the methodology of laser altimetry
- Understanding how elevation and shape information is derived from laser altimetry data
Exploring the Data
Data Type and Presentation
The MOLA data site provides raw and derived data products.Raw Data Products
Accessing the Data
The primary repository of data from the Mars Global Surveyor (MGS) Mission is the Planetary Data System (PDS (more info) ). To access data in the PDS, visit the PDS MOLA site, or go to the PDS Geosciences node, go to Mars Global Surveyor Data, and go to instrument, MOLA. The entire dataset is large so if you want to download many files, it's easier to use FTP. Wherever you see links to data files, you may download them using your web browser's "Save Target" function.
Users can also view MOLA data via the topographic map at Google Mars, which allows users to pan the map and zoom in on features of interest, including mountains, canyons, and ridges.
Manipulating Data and Creating Visualizations
Cartography can be something of an art form as well as literal mapping. To create images, obtain data in their binary integer, evenly sampled, simple cylindrical projection form (raw PDS .IMG files). Use a topography rendering program to apply a directional-derivative shade function and color contour function to the elevation.
Tools for Data Manipulation
Software to read and extract data from MOLA PEDR files is provided for Sun/UNIX, PC/Windows, and Macintosh platforms. The MOLA Science Team web site has the same software plus versions for additional platforms.
Some programs that can apply generic shading techniques:
About the Data
Limitations and Sources of Error
Error in MOLA measurements depends on the signal energy, pulse width, background level, and detector noise. By multiplying pulse reflection times by the speed of light, scientists can calculate MGS's altitude above the local terrain to within 30 meters (98 feet) or better. Knowledge of the MGS spacecraft position and the range of accuracy is sufficient to measure the topgraphy in smooth areas to an accuracy of a meter. Changes in topography due to the condensation and sublimation of carbon dioxide frost on the polar caps are measured to an accuracy of about 10-20 cm averaged over the whole of the cap.
References and Resources
Scientific References that Use this Dataset
- Zuber, M.T., D.E. Smith, S.C. Solomon, D.O. Muhleman, J.W. Head, J.B. Garvin, J.B. Abshire, J.L. Bufton (1992), The Mars Observer laser altimeter investigation. Journal of Geophysical Research, vol. 97(E5), 7781-7797.
- Kreslavsky, M. A., J. W. Head (2000), Kilometer-scale roughness of Mars: Results from MOLA data analysis. Journal of Geophysical Research, vol. 105(E11), 26695-26712.
- Bills, B. G., G. A. Neumann, D. E. Smith, and M. T. Zuber (2005), Improved estimate of tidal dissipation within Mars from MOLA observations of the shadow of Phobos, Journal of Geophysical Research, vol. 110(E7), 7004.
Education Resources that Use this Dataset
- Sakimoto, S. E., E. B. Grosfils, C.V. Mendelson, J. E. Bleacher (2001), The Mars 2000 Keck Undergraduate Research Project: Assessing the regional geology of the Cerberus Plains Region, Mars, American Geophysical Union, Spring Meeting 2001, abstract #ED21B-04.