Rover: Conditions Once Suited for Life on Mars   
       
   March 12, 2013: An analysis of a rock sample recently collected by NASA's   
   Curiosity rover shows ancient Mars could have supported living microbes.   
       
   "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."   
       
   Last month, Curiosity drilled into a sedimentary rock near an ancient stream   
   bed in Gale Crater. In the powder from the drill sample, scientists have   
   identified sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon -- some   
   of the key chemical ingredients for life.   
       
   http://www.nasa.gov/mission_pages/msl/multimedia/pia16833.html   
       
   These fine-grained sediments, likely deposited under water, suggest that Mars   
   could have supported ancient microbial life.  Data gathered by Curiosity   
   indicate a habitable environment characterized by neutral pH, chemical   
   gradients that would have created energy for microbes, and a distinctly low   
   salinity, which would have helped metabolism if microorganisms had ever been   
   present. More   
       
   "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.   
       
   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. (Red, like   
   rust, is a sign of oxidation.)   
       
   "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.   
       
   http://www.nasa.gov/mission_pages/msl/multimedia/pia16832.html   
       
   This false-color map shows the area within Gale Crater where NASA's Curiosity   
   rover landed on Aug. 5, 2012 PDT and the location where Curiosity collected   
   its first drilled sample at the "John Klein" rock. MoreClues 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.   
       
   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.   
       
   For updates, stay tuned to Science@NASA.   
       
       
    Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   More Information   
   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://www.nasa.gov/msl and h   
   tp://mars.jpl.nasa.gov/msl/ .   
       
   You can follow the mission on Facebook and Twitter at: http://ww   
   .facebook.com/marscuriosity and http://www.twitter.com/marscuriosity   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.9   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)