Mars Soil Not Too Extreme for Life
This image shows the trench informally called “Snow White.” Two samples were delivered to Phoenix’s Wet Chemistry Laboratory. Image Credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University. Credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University
Ever since the NASA Viking mission, which reached Mars in 1976, there has been considerable interest in the composition of Martian soils. Some Viking measurements indirectly suggested that the soils contained
highly oxidizing compounds, which could present extremely harsh conditions for life.
Recent observations from the Phoenix Mars Mission pointed to evidence of perchlorate, a potentially highly oxidizing compound, in the Martian soils. However, some studies have noted that because perchlorate is highly stable, its presence in Martian soils cannot explain the Viking measurements.
Quinn et al. present a new analysis of Mars soil samples using the Wet Chemistry Laboratory, a component of the Microscopy, Electrochemistry, and Conductivity Analyzer on the NASA Mars Phoenix Lander.
They find that although low levels of oxidizing compounds may be present, the oxidation-reduction potential of the soil is moderate and well within the range expected for habitable soils.
Source: Quinn et al. (2011) Geophysical Research Letters, doi:10.1029/2011GL047671