Science Guide

There was a bit of buzz this weekend about something in the Phoenix lander's chemical analysis of the martian soil. It turns out that this something is the detection of perchlorate (ClO₄^-). Right now, the team is working to ensure that the perchlorate is not a contaminant from the lander itself, as perchlorate is used as an oxidizer in rocket fuel; though this is unlikely given the depth of the sample and the kind of rockets used by Phoenix (ultrapure hydrazine). This indicates a significant chemical difference between martian and terrestrial soils. Further, the presence of such a highly reactive oxidizing agent would make the martian soil much less habitable.
[via Scientific American]