So what is brewing on Mars?

[Alex]

Not very exciting but here's a de-hyped recounting of the situation from wonderful astronomy blogger Emily Lakdawala. Essentially it is the opposite of what was inferred from the initial Aviation Week story. Rather than being positive news about the posibility of life on Mars there is dispositive news suggesting that organic life may have been pretty unlikely.

Key paragraphs:

• The Wet Chemistry Lab component of the MECA instrument has now analyzed two Mars soil samples. In both (I think), the MECA results indicate that one of the components of the soil may be an ion called perchlorate (ClO4-), which is an oxidizer. Oxidizers can do bad things to organic molecules, so its presence -- if confirmed -- would suggest that the past environment preserved in the soil at Phoenix' landing site was not conducive to life.
• HOWEVER, the TEGA instrument is also capable of detecting perchlorate. There have been two analyses of samples by TEGA. In one, the data could have been consistent either with the presence or absence of the perchlorate ion in the soil. In the other, the data suggested that perchlorate was NOT present.

The problem is that no special briefing happened. Without that, the "discovery concerning the potential for life' is suddenly much less interesting. The main goal of the Phoenix mission is to study the potential for past habitable environments on Mars; pretty much any measurement made by TEGA or MECA has some bearing on that question.