Carbon, sulfur, water and chlorine-containing substances, among other ingredients, were detected in samples Curiosity's arm delivered to an analytical laboratory inside the rover, the U.S. space agency reported Monday.
The rover's laboratory includes an instrument that used three methods to analyze gases given off from the dusty sand when it was heated in a tiny oven.
One class of substances the instrument checks for is organic compounds -- carbon-containing chemicals that can be ingredients for life. Although compounds made of carbon and chlorine can, in some cases, indicate microbes in the soil, the compounds detected could also be contamination from the Rover itself, scientists said.
"We have no definitive detection of martian organics at this point, but we will keep looking in the diverse environments of Gale Crater," said investigator Paul Mahaffy of NASA's Goddard Space Flight Center in Greenbelt, Md. "It's unclear if the carbon is martian or terrestrial."
The soil sample came from a drift of windblown dust and sand called "Rocknest" inside the Gale Crater.
The water detected by the instrument does not mean the area where the sample was taken was wet, scientists said; water molecules bound to grains of sand or dust are not unusual, although the quantity seen was higher than anticipated.
Curiosity is trying to assess whether areas inside the Gale Crater ever offered a habitable environment for microbes.
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