Thursday, March 14, 2013

Curiosity finds the Elements Necessary for Life

Rocks in Yellowknife Bay, Mars

On March 12, 2013 NASA announced that the Curiosity rover's on-board laboratory instruments, Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments, has detected the chemical building blocks of life on Mars. NASA scientists have found sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon near an ancient stream bed in Gale Crater on Mars last month. 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.

On August 6th 2012 at 1:32 am (eastern time) the Curiosity rover, a large mobile laboratory, was set down on Mars inside the Gale Crater by NASA’s Mars Science Laboratory, MSL, beginning a two-year investigation of Mars. The rover was designed to analyze samples scooped from the soil and drilled from rocks. The record of the planet's climate and geology is essentially "written in the rocks and soil" -- in their formation, structure, and chemical composition and this Mars mission is designed to unveil some of those secrets.  After the delays in the mission at year end, it is amazing that this discovery was made so early in the mission.

Curiosity carries a radioisotope power system that generates electricity from the heat of plutonium's radioactive decay. This power source gives the mission an operating lifespan on Mars' surface of a full Martian year (687 Earth days) or more and hopefully be able to gather enough data to assess what the Martian environment was like in the past. 

The rock analyzed so far 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 identified in previous Mars missions, was not harshly oxidizing, acidic or extremely salty. According to Michael Meyer, lead scientist for NASA's Mars Exploration Program at the agency's headquarters in Washington these findings are evidence that Mars could have once supported a habitable environment for microbial life.

Rover Path on Mars
In addition to sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon 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. 

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