[meteorite-list] NASA Research Offers New Prospect Of Water On Mars

[Ron Baalke]

July 01, 2011

Dwayne Brown 
Headquarters, Washington      
202-358-1726 
dwayne.c.brown at nasa.gov 

Rachel Hoover 
Ames Research Center, Moffett Field, Calif. 
650-604-4789 
rachel.hoover at nasa.gov 

Karen Randall 
SETI Institute, Mountain View, Calif. 
650-960-4537 
krandall at seti.org   


RELEASE: 11-214

NASA RESEARCH OFFERS NEW PROSPECT OF WATER ON MARS

WASHINGTON -- NASA scientists are seeing new evidence that suggests 
traces of water on Mars are under a thin varnish of iron oxide, or 
rust, similar to conditions found on desert rocks in California's 
Mojave Desert. 

Mars could be spotted with many more patches of carbonates than 
originally suspected. Carbonates are minerals that form readily in 
large bodies of water and can point to a planet's wet history. 
Although only a few small outcrops of carbonates have been detected 
on Mars, scientists believe many more examples are blocked from view 
by the rust. The findings appear in the Friday July 1, online edition 
of the International Journal of Astrobiology. 

"The plausibility of life on Mars depends on whether liquid water 
dotted its landscape for thousands or millions of years," said Janice 
Bishop, a planetary scientist at NASA's Ames Research Center at the 
SETI Institute at Moffett Field, Calif., and the paper's lead author. 
"It's possible that an important clue, the presence of carbonates, 
has largely escaped the notice of investigators trying to learn if 
liquid water once pooled on the Red Planet." 

Scientists conduct field experiments in desert regions because the 
extremely dry conditions are similar to Mars. Researchers realized 
the importance of the varnish earlier this year when Bishop and Chris 
McKay, a planetary scientist at Ames investigated carbonate rocks 
coated with iron oxides collected in a location called Little Red 
Hill in the Mojave Desert. 

"When we examined the carbonate rocks in the lab, it became evident 
that an iron oxide skin may be hindering the search for clues to the 
Red Planet's hydrological history," McKay said. "We found that the 
varnish both altered and partially masked the spectral signature of 
the carbonates." 

McKay also found dehydration-resistant blue-green algae under the rock 
varnish. Scientists believe the varnish may have extended temporarily 
the time that Mars was habitable, as the planet's surface slowly 
dried up. 

"The organisms in the Mojave Desert are protected from deadly 
ultraviolet light by the iron oxide coating," McKay said. "This 
survival mechanism might have played a role if Mars once had life on 
the surface." 

In addition to being used to help characterize Mars' water history, 
carbonate rocks also could be a good place to look for the signatures 
of early life on the Red Planet. Every mineral is made up of atoms 
that vibrate at specific frequencies to produce a unique fingerprint 
that allows scientists to accurately identify its composition. 

Research data were similar to observations provided by NASA's Mars 
Reconnaissance Orbiter (MRO) spacecraft, as it orbited an ancient 
region of Mars called Nili Fossae. The area revealed the strongest 
carbonate signature ever found. Although MRO recently detected small 
patches of carbonates, approximately 200-500 feet wide, on the 
Martian surface, the Mojave study suggests more patches may have been 
overlooked because their spectral signature could have been changed 
by the pervasive varnish. 

"To better determine the extent of carbonate deposits on Mars, and by 
inference the ancient abundance of liquid water, we need to 
investigate the spectral properties of carbonates mixed with other 
minerals," Bishop said. 

The varnish is so widespread that NASA's Mars Exploration Rovers, 
Spirit and Opportunity, used a motorized grinding tool to remove the 
rust-like overcoat on rocks before other instruments could inspect 
them. In 2010, scientists using data collected by Spirit also 
identified a small carbonate outcrop at a crater called Gusev. NASA's 
newest and most capable rover, the Mars Science Laboratory Curiosity 
is schedule to launch in November. It will use tools to study whether 
the Mars had environmental conditions favorable for supporting 
microbial life and favorable for preserving clues about whether life 
existed. 

Launched in 2006, MRO observes Mars' surface, subsurface and 
atmosphere in unprecedented detail. Opportunity and Spirit completed 
their three-month prime missions on Mars in April 2004, but continued 
to collect data. NASA ended operations for Spirit this year to focus 
only on Opportunity activities. NASA's Jet Propulsion Laboratory in 
Pasadena manages MRO, Mars rovers and Curiosity for NASA's Science 
Mission Directorate in Washington. For more information about NASA's 
Mars missions, visit: 

http://www.nasa.gov/mars   
	
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