Global Map Reveals Mineral Distribution on Mars (Forwarded)

Applied Physics Laboratory
Johns Hopkins University
Laurel, Maryland

Media Contacts:
J. Huergo, Johns Hopkins University Applied Physics Laboratory
(240) 228-5618

December 19, 2007

Global Map Reveals Mineral Distribution on Mars

Scientists are getting a clearer image of mineral distribution on the
surface of Mars, thanks to the Compact Reconnaissance Imaging Spectrometer
for Mars (CRISM), one of six science instruments on NASA's Mars
Reconnaissance Orbiter, currently circling the planet. More than 200
just-released "spectral maps" reveal the distribution of various minerals
on the surface of Mars -- the first installment of the Global Mars Map,
which will eventually cover the entire planet.

The locations and amounts of these minerals provide clues about the
geological processes that created different rock formations, and will
provide invaluable pointers to when and where liquid water once existed on
Mars. These first maps were selected to cover many of the geologically
most interesting parts of the planet and represent about 11 percent of
Mars' surface.

Built and operated by the Johns Hopkins University Applied Physics
Laboratory (APL), CRISM detects 544 wavelengths of visible and infrared
sunlight reflecting off of the planet's surface. Minerals on the planet
absorb some of this sunlight, leaving telltale gaps or absorptions in the
spectra of the reflected light.

To create the maps, CRISM uses a multispectral survey mode of operation,
collecting data from just 13 percent of the available wavelengths to
highlight key mineral groups. This lower data-rate mode, coupled with
other onboard data compression, decreases the data volume significantly
and makes it possible for CRISM to extend its measurements beyond a few
thousand targets to cover the entire planet.

Each section, or tile, of the Global Mars Map shows a visible-infrared
image of a swatch of the planet's surface about 300 kilometers (186 miles)
wide, overlaid with 10 kilometer- (6.2 mile-) wide strips of the CRISM
spectral data. By creating the map tiles, the CRISM team is providing
scientists with a unique tool in the form of uniformly processed data,
saving them from the lengthy task of processing the image strips
themselves.

This initial release of map tiles includes fully calibrated measurements,
but without any correction for the obscuring effects of Mars' atmosphere.
For the future, we're working on an experimental correction for the
atmospheric effects and a series of 'summary' tiles that will capture key
information about surface composition," says APL's Scott Murchie, CRISM
principal investigator.

"We'll continue to add to the Global Mars Map until we've mapped the
entire planet, in 1,964 tiles," says Christopher Hash of Applied Coherent
Technology, Inc., in Herndon, VA, which is responsible for the specialized
software to produce the tiles.

Researchers can access the Global Mars Map through NASA's Planetary Data
System Geosciences Node. Samples of the tiles can be found under "Featured
Images" on the CRISM home page.

APL, which has built more than 150 spacecraft instruments over the past
four decades, led the effort to develop, integrate and test CRISM. The
CRISM team includes experts from universities, government agencies and
small businesses in the United States and abroad; visit
http://crism.jhuapl.edu for more information.

Information about the Mars Reconnaissance Orbiter and Mars Science
Laboratory missions is available online at
http://mars.jpl.nasa.gov/
The Jet Propulsion Laboratory, a division of the California Institute of
Technology, manages the MRO mission for the NASA Science Mission
Directorate, Washington. Lockheed Martin Space Systems, Denver, is the
prime contractor and built the MRO spacecraft.

[NOTE: Images supporting this release are available at
http://www.jhuapl.edu/newscenter/pressreleases/2007/071219.asp ]


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