[meteorite-list] Mars Rovers Spot Water-Clue Mineral, Frost, Clouds

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon Dec 13 18:07:41 2004
Message-ID: <200412132307.PAA00275_at_zagami.jpl.nasa.gov>

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

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

Donald Savage (202) 358-1547
NASA Headquarters, Washington, D.C.

News Release: 2004-287 December 13, 2004

Mars Rovers Spot Water-Clue Mineral, Frost, Clouds

Scientists have identified a water-signature mineral called
goethite in bedrock that the NASA's Mars rover Spirit
examined in the "Columbia Hills," one of the mission's
surest indicators yet for a wet history on Spirit's side of
Mars.

"Goethite, like the jarosite that Opportunity found on the
other side of Mars, is strong evidence for water activity,"
said Dr. Goestar Klingelhoefer of the University of Mainz,
Germany, lead scientist for the iron-mineral analyzer on
each rover, the Moessbauer spectrometer. Goethite forms only
in the presence of water, whether in liquid, ice or gaseous
form. Hematite, a mineral that had previously been
identified in Columbia Hills bedrock, usually, but not
always, forms in the presence of water.

The rovers' main purpose is to look for geological evidence
of whether their landing regions were ever wet and possibly
hospitable to life. The successful results so far -- with
extended missions still underway -- advance a NASA goal of
continuing Mars exploration by robots and, eventually, by
humans, said Doug McCuistion, Mars Exploration Program
Director at NASA Headquarters.

Klingelhoefer presented the new results from a rock in the
"West Spur" of Mars' "Husband Hill" at a meeting of the
American Geophysical Union in San Francisco this week.

Spirit has now driven past the West Spur to ascend Husband
Hill itself. One remaining question is whether water was
only underground or ever pooled above the surface, as it did
at Opportunity's site. "As we climb Husband Hill and
characterize the rock record, we'll be looking for
additional evidence that the materials were modified by
ground water and searching for textural, mineralogical and
chemical evidence that the rocks were formed in or modified
by surface water," said Dr. Ray Arvidson of Washington
University in St. Louis, deputy principal investigator for
the rover instruments.

The amount of worrisome friction in Spirit's right front
wheel has been decreasing. Meanwhile, rover wranglers at
NASA's Jet Propulsion Laboratory in Pasadena, Calif.,
continue to minimize use of that wheel by often letting it
drag while the other five wheels drive. "Babying that wheel
seems to be helping," said JPL's Jim Erickson, rover project
manager. Both rovers continue working in good health about
eight months after their primary three-month missions.
"Looks as though Spirit and Opportunity will still be with
us when we celebrate the landing anniversaries in January,"
Erickson said.

Opportunity has completed six months of inspecting the
inside of "Endurance Crater" and is ready to resume
exploration of the broad plains of the Meridiani region. It
has recently seen frost and clouds marking the seasonal
changes on Mars. At this week's conference, rover science-
team member Dr. Michael Wolff of the Brookfield, Wisconsin
branch of the Boulder, Colorado-based Space Science
Institute is reporting those and other atmospheric
observations. "We're seeing some spectacular clouds," Wolff
said. "They are a dramatic reminder that you have weather on
Mars. Some days are cloudy. Some are clear."

A portion of Mars' water vapor is moving from the north pole
toward the south pole during the current northern-summer and
southern-winter period. The transient increase in
atmospheric water at Meridiani, just south of the equator,
plus low temperatures near the surface, contribute to
appearance of the clouds and frost, Wolff said. Frost shows
up some mornings on the rover itself. The possibility that
it has a clumping effect on the accumulated dust on solar
panels is under consideration as a factor in unexpected
boosts of electric output from the panels.

As its last major endeavor inside Endurance Crater,
Opportunity made a close inspection of rock layers exposed
in a part of the crater wall called "Burns Cliff." Dr.
Steve Squyres of Cornell University, Ithaca, N.Y., principal
investigator for the rover instruments, said, "In the lower
portion of the cliff, the layers show very strong
indications that they were last transported by wind, not by
water like some layers higher up. The combination suggests
that this was not a deep-water environment but more of a
salt flat, alternately wet and dry."

JPL has managed the Mars Exploration Rover project since it
began in 2000. Images and additional information about the
rovers and their discoveries are available on the Internet
at
http://www.nasa.gov/vision/universe/solarsystem/mer_main.htm
l and at http://marsrovers.jpl.nasa.gov . Information about
NASA and agency programs is available on the Web at
http://www.nasa.gov .
                              
                            -end-
Received on Mon 13 Dec 2004 06:07:34 PM PST