03.12.2013
Source: Jet Propulsion Laboratory
Two Different Aqueous Environments
This set of images compares rocks seen by NASA's Opportunity rover and Curiosity rover at two different parts of Mars.
PASADENA, Calif. -- An analysis of a rock sample collected by NASA's Curiosity rover shows ancient Mars could have
supported living microbes.
Scientists identified sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon -- some of the key chemical ingredients
for life -- in the powder Curiosity drilled out of a sedimentary rock near an ancient stream bed in Gale Crater on the
Red Planet last month.
"A fundamental question for this mission is whether Mars could have supported a habitable environment," said Michael
Meyer, lead scientist for NASA's Mars Exploration Program at the agency's headquarters in Washington. "From what we know
now, the answer is yes."
Clues to this habitable environment come from data returned by the rover's Sample Analysis at Mars (SAM) and Chemistry
and Mineralogy (CheMin) instruments. The data indicate the Yellowknife Bay area the rover is exploring was the end of an
ancient river system or an intermittently wet lake bed that could have provided chemical energy and other favorable
conditions for microbes. The rock is made up of a fine-grained mudstone containing clay minerals, sulfate minerals and
other chemicals. This ancient wet environment, unlike some others on Mars, was not harshly oxidizing, acidic or
extremely salty.
The patch of bedrock where Curiosity drilled for its first sample lies in an ancient network of stream channels
descending from the rim of Gale Crater. The bedrock also is fine-grained mudstone and shows evidence of multiple periods
of wet conditions, including nodules and veins.
Curiosity's drill collected the sample at a site just a few hundred yards away from where the rover earlier found an
ancient streambed in September 2012.
"Clay minerals make up at least 20 percent of the composition of this sample," said David Blake, principal investigator
for the CheMin instrument at NASA's Ames Research Center in Moffett Field, Calif.
These clay minerals are a product of the reaction of relatively fresh water with igneous minerals, such as olivine, also
present in the sediment. The reaction could have taken place within the sedimentary deposit, during transport of the
sediment, or in the source region of the sediment. The presence of calcium sulfate along with the clay suggests the soil
is neutral or mildly alkaline.
Studying Habitability in Ancient Martian Environments
This set of images shows the results from the rock abrasion tool from NASA's Mars Exploration Rover Opportunity (left)
and the drill from NASA's Curiosity rover (right).
Scientists were surprised to find a mixture of oxidized, less-oxidized, and even non-oxidized chemicals, providing an
energy gradient of the sort many microbes on Earth exploit to live. This partial oxidation was first hinted at when the
drill cuttings were revealed to be gray rather than red.
"The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as
sulfates and sulfides that indicate a possible chemical energy source for micro-organisms," said Paul Mahaffy, principal
investigator of the SAM suite of instruments at NASA's Goddard Space Flight Center in Greenbelt, Md.
An additional drilled sample will be used to help confirm these results for several of the trace gases analyzed by the
SAM instrument.
"We have characterized a very ancient, but strangely new 'gray Mars' where conditions once were favorable for life,"
said John Grotzinger, Mars Science Laboratory project scientist at the California Institute of Technology in Pasadena,
Calif. "Curiosity is on a mission of discovery and exploration, and as a team we feel there are many more exciting
discoveries ahead of us in the months and years to come."
Scientists plan to work with Curiosity in the "Yellowknife Bay" area for many more weeks before beginning a long drive
to Gale Crater's central mound, Mount Sharp. Investigating the stack of layers exposed on Mount Sharp, where clay
minerals and sulfate minerals have been identified from orbit, may add information about the duration and diversity of
habitable conditions.
NASA's Mars Science Laboratory Project has been using Curiosity to investigate whether an area within Mars' Gale Crater
ever has offered an environment favorable for microbial life. Curiosity, carrying 10 science instruments, landed seven
months ago to begin its two-year prime mission. NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the
project for NASA's Science Mission Directorate in Washington.
For more about the mission, visit: http://mars.jpl.nasa.gov/msl . You can follow the mission on Facebook and Twitter at: http://www.facebook.com/marscuriosity and http://www.twitter.com/marscuriosity
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