March 12, 2013
Curiosity Finds First Hard Evidence That Mars May Have Hosted Life
Lee Rannals for redOrbit.com - Your Universe Online
NASA announced today that the powder that Curiosity drilled out of a sedimentary rock on Mars showed the presence of sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon — all of which are key chemical ingredients for life.
"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."
Curiosity made its first drill into "John Klein" rock on February 8, drilling a 0.63-inch wide and 2.5-inches deep hole. After drilling, the rover extended its arm and collected a sample of the rock to deliver for analysis inside its Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments. When the rock sample was heated by the SAM instrument in a quartz oven to 1,535 degrees Fahrenheit, it showed the presence of water, carbon dioxide, oxygen, sulfur dioxide and hydrogen sulfide.
According to NASA, the data has revealed that Curiosity is sitting on the end of an ancient river system or an intermittently wet lake bed that could have provided chemical energy and other favorable conditions for living microbes. While many scientists have speculated about these results in the past, this is some of the first tangible evidence ever obtained to show Mars once had the right conditions for microbial life.
The John Klein rock, named after a former Mars Science Laboratory deputy project manager who died in 2011, is made up of fine-grained mudstone containing clay and sulfate minerals as well as other chemicals. NASA says this ancient wet environment was not harshly oxidizing, acidic or extremely salty.
The bedrock where Curiosity drilled its first sample contains an ancient network of stream channels that descend from the rim of Gale Crater. Like John Klein rock, this bedrock is also fine-grained mudstone and shows evidence of multiple periods of wet conditions, including features like nodules and veins.
"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.
According to NASA, the clay minerals found come from the reaction of relatively fresh water with igneous minerals like olivine. The reaction could have taken place within the sedimentary deposit, during the transport of the sediment. NASA also said the presence of calcium sulfate along the clay suggests that the soil was neutral or mildly alkaline.
Scientists say they were surprised to find a mixture of oxidized, less-oxidized and even non-oxidized chemicals in the sample.
"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.
Drilling into the Martian rock unveiled a layer of gray rather than the iconic red the planet is known for, showing some of the first signs of partial oxidation.
"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."
Last week the Curiosity team faced a bit of a delay after the rover reported a memory glitch with the main computer system. The team had to put Curiosity into "safe mode" to investigate the main computer before putting the rover back to work.