Reaching its first 100 days of operations, the
powerful mineral detector aboard the newest satellite to
circle Mars is changing the way scientists view the history
of water on the red planet.
The Compact Reconnaissance Imaging Spectrometer for
Mars, designed and built by Johns Hopkins'
Applied Physics
Laboratory, has teamed with the five other cameras and
sensors aboard NASA's Mars Reconnaissance Orbiter to
provide new clues about where water could have existed on
or near the Martian surface.
"We're finding that Mars has even more compositional
diversity and complicated geology than had been revealed by
instruments on other Mars orbiters," said Scott Murchie,
CRISM principal investigator from APL. "With CRISM's help,
this mission is going to rewrite our understanding of the
planet."
Sue Smrekar, deputy MRO project scientist at NASA's
Jet Propulsion Laboratory, Pasadena, Calif., said, "CRISM's
high spatial resolution provides the means to not only
identify a greater range of minerals on Mars but also to
associate them with small-scale geologic features. The
result is a tremendous leap forward in interpreting the
geologic processes and volatile environments that created
different rocks throughout the history of Mars."
Since beginning its primary science phase in November
2006, the orbiter has sent home enough data to fill nearly
1,000 compact discs, quickly matching the record for Mars
data returned over nine years by NASA's Mars Global
Surveyor.
About 30 percent of MRO's data has come from CRISM.
Through its telescopic scanners, the instrument has taken
more than 700 images of specific targets, including more
than 250 at high resolution that pinpoint areas down to 48
feet in 544 "colors" of reflected sunlight. The camera also
has mapped nearly a quarter of the planet at lower
resolution--showing areas as small as 660 feet in 72
colors--and monitored abundances of atmospheric gases and
particulates in the atmosphere, returning more than 500
separate measurements that track seasonal variations.
"We started mapping in northern Martian summer, so
we're able to compile a nearly complete map of the ices and
minerals present in and around the north polar cap," said
Frank Seelos, CRISM science operations lead from APL.
Some CRISM images reveal unprecedented details of
geologic processes on Mars, such as intricate compositional
layering of the polar caps, and ancient rocks from Mars'
earliest history that record a time when liquid water was
pervasive and long-lasting. Its coverage of the north polar
region is providing new insight into the vast field of
gypsum-rich sand dunes that surrounds the polar cap. Over
the past three months, the CRISM team has placed several of
these images on the Web at:
crism.jhuapl.edu
and the team members plan to discuss the data in papers to
be published this spring.
CRISM's resolution in near-infrared wavelengths is
about 20 times sharper than any previous look at Mars at
these wavelengths. The instrument is searching for areas
that were wet long enough to leave a mineral signature on
the surface, looking for the spectral traces of aqueous and
hydrothermal deposits, and mapping the geology, composition
and stratigraphy of surface features. By identifying sites
most likely to have contained water, CRISM data will help
determine the best potential landing sites for future Mars
missions seeking fossil traces of past life.
NASA's Phoenix mission team is using data from CRISM
and other high-resolution MRO instruments to support
landing-site selection for its spacecraft, scheduled to
touch down in the northern Martian plains in May 2008.
Phoenix will determine the composition of both dry surface
soil and ice-rich subsurface soil; CRISM's infrared
sensitivity to the ice and salts typically found on Mars
has proven valuable in helping the team find sites with
ready access to both features.
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; for more
information, go to:
crism.jhuapl.edu.
Information about the Mars Reconnaissance Orbiter is
available online at:
www.nasa.gov/mro.
The mission is managed by the Jet Propulsion Laboratory, a
division of the California Institute of Technology, for the
NASA Science Mission Directorate, Washington. Lockheed
Martin Space Systems, Denver, is the prime contractor and
built the MRO spacecraft.
GO TO