'Dandruff' could contaminate Phoenix landing site

Published online 6 June 2008 | Nature | doi:10.1038/news.2008.878

Dead microbes and skin flakes from Earthlings may scupper the search for organic molecules.

Eric Hand

The most detailed photo ever of martian dust - but Phoenix may have less success in finding organic molecules.NASA/JPL-Caltech/Univ.

ArizonaCould Phoenix’s search for organic molecules on Mars be foiled by dandruff from Earth? After a successful landing last month on the planet’s northern plains, the NASA spacecraft is busily scraping through the martian dirt. Next week, the mission team plans to use one of its premier instruments, the Thermal and Evolved Gas Analyzer (TEGA), to test its first baked soil sample for molecules containing carbon.

The search for the organic building blocks of life has been a major selling point for Phoenix; many press accounts have eagerly, yet mistakenly, foreshortened the mission’s raison d’etre to ‘the search for life’. Yet some mission scientists say that it is the science goal least likely to succeed, partly because TEGA is so sensitive that it may end up sensing only contamination from Earth.

“We will see organics, for sure, because we’re bringing them,” says Aaron Zent, a mission scientist from NASA’s Ames Research Center in California. Likely contaminants include skin flakes, dead microbes and volatile lubricants. “The problem with an instrument so sensitive is all you detect is your own schmutz,” says Zent.

Full article here:

http://www.nature.com/news/2008/080606/full/news.2008.878.html