Mars habitable one day, inhabitable next?

Looks like my hopes of meeting a Martian is fading. Aviation Week which first reported that the White House was briefed by NASA about potential of life on Mars now say that the Phoenix data is like to be more negative and that no life has been found on Mars by the Phoenix lander. Darn it! From Aviation Week:

AviationWeek.com reported Aug. 1 and Aviation Week & Space Technology reports today that the new information involves the "potential for life" on Mars. That potential can either be positive or negative, and the new data indicate the new soil tests are at best inconclusive, according to the information being released on the soil chemistry experiment.

An initial soil test by the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument indicated that the soil is highly Earth-like. The second test, however, is leading scientists to view the data as more inconclusive.

Other media outlets and websites around the world incorrectly reported that the "potential for life" meant that actual life on Mars had been detected. Coverage by Aviation Week states that the wet chemistry experiment can not detect life, nor can any other Phoenix instrument such as the Thermal and Evolved Gas Analyzer (TEGA) organics experiment.

A substance called perchlorate, a natural and manmade highly oxidizing salt sometimes found in soil and groundwater, has been found in the second Martian soil test. Perchlorate is the main ingredient in solid rocket fuel and NASA's Phoenix scientists are now investigating whether the substance could have gotten there by contamination before launch. From AP:

Phoenix detected the salt through a chemistry experiment. The lander mixed soil with water brought from Earth into a teacup-size beaker and stirred it. Two dozen sensors inside the beaker detect the soil's pH and probe for traces of mineral nutrients.

The first test determined the soil was slightly alkaline and contained nutrients such as magnesium, sodium, potassium and chloride necessary for living things. The second test found the highly reactive perchlorate.

Scientists want to confirm their results because another Phoenix instrument that bakes and sniffs soil samples found no evidence of perchlorate during a run on Sunday.

Previously: NASA finds Martians, briefs White House before announcing to public