A leading NASA scientist has been speaking about the possibility of finding life on the planet Mars.
Chris McKay of the NASA Ames Research Centre is a co-investigator on NASA's Phoenix Lander mission, which detected perchlorates, (ClO4), in the Martian soil in June and July 2008.
McKay has been interviewed by the US Planetary Society for their weekly radio show.
In the interview McKay states ...
1% of the martian soil at the Phoenix lander site is perchlorate.
Perchlorates can coexist with organic molecules at room temperature, but when heated the perchlorate decomposes releasing oxygen which attacks organic molecules, destroying them.
In 1976 two life detection experiments on NASA's Viking 1 and 2 landers ( the labelled released and gas exchange experiment ) delivered results that were consistent with biological activity.
The Viking landers were also equipped with a GCMS experiment which heated Mars soil samples to several hundred degrees and looked for organic fragments being released. None were found at a concentration of
1 part per billion.
As a result most scientists concluded the data obtained by the life detection experiments were false positives caused by inorganic chemical processes.
But McKay says that if perchlorates were present in the soil at the Viking landing sites the GCMS experiment would have destroyed organic molecules in the Martian soil before it could detect them, providing an explanation for the unusual finding of no organics at all in the Martian soil at the Viking lander sites.
McKay thinks its time to re-evaluate the Viking results and says we should get the first accurate measurement of the concentration of organic molecules in the Martian soil when the Mars Science Laboratory lander starts work in 2012. It'll search for organics by dissolving them in solution - without heating the sample.
This way any organics won't be removed by perchlorate activity.