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| 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.
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| 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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