[meteorite-list] NASA Orbiter Reveals New Details of Mars, Young and Old (MRO)

[Ron Baalke]

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE  818-354-5011
http://www.jpl.nasa.gov

Guy Webster  818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.

Erica Hupp  202-358-1237	
NASA Headquarters, Washington 						 
News Release: 2006-131			 Oct. 16, 2006                                                                
NASA Orbiter Reveals New Details of Mars, Young and Old

During its first week of observations from low orbit, 
NASA's newest Mars spacecraft is already revealing new 
clues about both recent and ancient environments on the 
red planet.

Scientists hope the Mars Reconnaissance Orbiter will 
answer questions about the history and distribution of 
Mars' water by combining data from the orbiter's 
high-resolution camera, imaging spectrometer, context 
camera, ground-penetrating radar, atmospheric sounder, 
global color camera, radio and accelerometers.

Between Sept. 29 and Oct. 6, science instruments on the 
spacecraft viewed dozens of sites that reflect different 
episodes in Mars' history. The diverse sites provide a 
good test for the capabilities of the spacecraft 
instruments. The orbiter will begin its primary science 
mission phase in early November when Mars re-emerges from 
passing nearly behind the sun. 

The instruments are seeing details in the shapes and icy 
composition of geologically young layering near the Martian 
north pole. Other views offer details of a mid-latitude 
valley whose upper layers have been eroded away, revealing 
an underlying clay layer that formed a few billion years ago, 
when wet conditions produced the clay. Observations of a 
southern-hemisphere crater show fine-scale details of more 
recent gullies, adding evidence that they were carved by 
flowing water.

"In this opening phase we have tested the instruments, and 
they are working perfectly," said Dr. Steve Saunders, Mars 
Reconnaissance Orbiter program scientist at NASA 
Headquarters, Washington. "The teams are getting amazing 
science data. They are ready to fulfill the mission's 
science objectives and to support other Mars missions. One 
image is already helping the Mars Exploration Rover team 
choose a route to explore Victoria Crater. Others will help 
guide the selection of a safe site for the future Phoenix 
Mars Lander."

In Chasma Boreale, a vast valley that juts into the north 
polar ice cap, the orbiter's spectrometer sees layers that 
vary in soil composition and in how much ice is mixed with 
the soil. A dark underlying layer contains little ice, but 
just beneath it lies ice-rich material resembling higher 
layers. The spectrometer takes pictures both in 
visible-light and infrared wavelengths useful for 
identifying what a target is made of.

"You see more-ice-rich and less-ice-rich layers, which 
tells you that conditions changed from the time one layer 
was deposited to the time another layer was deposited," 
said Dr. Scott Murchie of Johns Hopkins University Applied 
Physics Laboratory, Laurel, Md. Murchie is the principal 
investigator for the spectrometer on the spacecraft. 
"These layers are geologically young -- on the order of 
thousands or millions of years -- and may hold clues about 
climate cycles." 

A lower-latitude target was Mawrth Vallis. The European 
Mars Express spacecraft previously discovered ancient 
deposits of clay minerals that could form only if water 
were present for a long time at Mawrth Vallis. The Mars 
Reconnaissance Orbiter's spectrometer has resolved 
smaller-scale compositional features and detected differing 
clay mineral content. The clay-rich areas show some of 
the best evidence for conditions possibly favorable for 
life on ancient Mars, Murchie said.

The mission's High Resolution Imaging Science Experiment 
camera has shown unprecedented detail in orbital images of 
Mars. An example was released recently showing the 
Opportunity rover at Victoria Crater. The camera imaged 64 
areas on Mars during the testing week. "These images are 
truly beautiful, and since they resolve features the size 
of people, you can visualize yourself hiking around in 
these diverse terrains," said the camera's principal 
investigator, Dr. Alfred McEwen of the University of 
Arizona, Tucson.

The high-resolution camera, the imaging spectrometer and 
the orbiter's wider-looking Context Camera all observed 
Mawrth Vallis. Details visible in the new observations, 
such as small channels, are consistent with past wet 
conditions, McEwen said. 

Another observation of an unnamed southern crater shows 
relatively young gullies, like those seen in many Mars 
locations viewed by NASA's Mars Global Surveyor orbiter. 
Braided channels characteristic of sediment-rich streams 
are visible in the new observations. This reinforces the 
interpretation that these geologically young gullies 
formed at least in part from erosion by flowing water. 
Original discovery of the many geologically young 
gullies on Martian slopes was by Dr. Michael Malin of 
Malin Space Science Systems, San Diego.

The Mars Reconnaissance Orbiter is managed by the Jet 
Propulsion Laboratory, Pasadena, Calif., for NASA's 
Science Mission Directorate, Washington. For more 
information, visit 

http://www.nasa.gov/mro .
 
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