The first chemical lab results beamed back from the Phoenix lander in the deathly cold martian arctic show that life could get along just fine there, given a bit of liquid water. But there's still no evidence that organisms could have populated the area in the past.
The latest results come from the lander's Microscopy, Electrochemistry, and Conductivity Analyzer (MECA), where "we're making mud and stirring it with sensors," as team member Michael Hecht of NASA's Jet Propulsion Laboratory in Pasadena, California, put it. About a cubic centimeter of soil mixed with sterile water brought from Earth had a pH of 8 to 9 and contained magnesium, sodium, potassium, and chloride. "Earth-type life would be happy to live in this soil," Phoenix team member Samuel Kounaves of Tufts University in Medford, Massachusetts, said at a media teleconference today. "You could grow asparagus but not [acid-loving] strawberries" in the alkaline dirt.
The conditions are reminiscent of soil in Antarctica's Dry Valleys, Kounaves said, referring to the hyperarid, ice-free regions where the merest wisp of life hangs on. There, the surface soil is also alkaline and low in salts, but deeper it can turn saline and acidic as the "ice table" is approached, he said.
Still, Kounaves emphasized that the results are preliminary, and they do not address the mission's prime goal of determining whether this spot ever harbored liquid water and was therefore habitable. MECA cannot measure phosphorus, an essential terrestrial nutrient, and results for nitrogen, another essential element, will take another few days, he said. Phoenix will also remain silent on possible life showstoppers such as arsenic, which it can't detect.
Meanwhile, the lander will keep digging and analyzing deeper--toward the subsurface ice reported last week (ScienceNOW, 20 June), in search of water's history on Mars.
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