NASA is finally receiving data on Martian soil samples from Curiosity, its rover currently traversing the red planet. The results from the soil samples hint at something exciting, but rover scientists are making very sure not to raise expectations.
NASA had always planned to present early results from the mission this week at a press conference. But expectations for the press conference soared after one of the instruments on board the rover appeared to detect organic molecules.
Having already found signs of water on Mars, finding signs of organic material would be another piece of evidence that there might might, might have once been life on Mars.
Paul Mahaffey, the lead scientist on Curiosity's main analysis instrument, known as the Scientific Analysis at Mars, or SAM, device, says no news yet.
"SAM has no definitive detection to report of organic compounds with these first set of experiments," he told a meeting of the American Geophysical Union in San Francisco Monday.
Mahaffey says SAM definitely saw simple organic compounds, compounds made of carbon, when it analyzed its first soil sample last month. It also saw compounds made with chlorine.
"The reason we're saying we have no definitive detection of Martian organics," Mahaffey says, "is that we have to be very careful to make sure both the carbon and the chlorine are coming from Mars."
Mahaffey says NASA cleaned the instrument before it left Earth, and cleaned it some more once it got to Mars. But he says it's still possible the carbon that the instrument is seeing may be a contaminant from Earth.
And Mahaffey emphasized that the carbon compounds if they really are in the soil sample may simply be inorganic carbon created by a non-biological chemical reaction. But if Curiosity did find carbon molecules, even inorganic carbon, that would be a sign that organic carbon could potentially exist on Mars and might be discoverable.
John Grotzinger of the California Institute of Technology, Curiosity's chief scientist, said it will take a while to make sense of all the data coming from the rover's suite of instruments.
"There's not going to be one single moment where we all stand up and, on the basis of a single measurement, have a hallelujah moment," he says.
Grtozinger says that's just the way it works in science.