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Sensor Being Developed to Check for Life on Mars
03.02.07
exomars NASA-funded researchers are refining a tool that could not only check for the faintest traces of life's molecular building blocks on Mars, but could also determine whether they have been produced by anything alive.
Right: Artist's concept of ExoMars. Image courtesy: European Space Agency
The instrument, called Urey: Mars Organic and Oxidant Detector, has already shown its capabilities in one of the most barren climes on Earth, the Atacama Desert in Chile. The European Space Agency has chosen this tool from the United States as part of the science payload for the ExoMars rover planned for launch in 2013. Last month, NASA selected Urey for an instrument-development investment of $750,000.
The European Space Agency plans for the ExoMars rover to grind samples of Martian soil to fine powder and deliver them to a suite of analytical instruments, including Urey, that will search for signs of life. Each sample will be a spoonful of material dug from underground by a robotic drill.
"Urey will be able to detect key molecules associated with life at a sensitivity roughly a million times greater than previous instrumentation," said Dr. Jeffrey Bada of Scripps Institution of Oceanography at the University of California, San Diego. Bada is the principal investigator for an international team of scientists and engineers working on various components of the device.
To aid in interpreting that information, part of the tool would assess how rapidly the environmental conditions on Mars erase those molecular clues.
Dr. Pascale Ehrenfreund of the University of Leiden in the Netherlands, said, "The main objective of ExoMars is to search for life. Urey will be a key instrument for that because it is the one with the highest sensitivity for organic chemicals." Ehrenfreund, one of two deputy principal investigators for Urey, coordinates efforts of team members from five other European countries.
Urey can detect several types of organic molecules, such as amino acids, at concentrations as low as a few parts per trillion.
Urey instrument Left: Urey Instrument. Click browse view to see instrument labels. Image credit: NASA/JPL/UCSD. + Read More
All life on Earth assembles chains of amino acids to make proteins. However, amino acids can be made either by a living organism or by non-biological means. This means it is possible that Mars has amino acids and other chemical precursors of life but has never had life. To distinguish between that situation and evidence for past or present life on Mars, the Urey instrument team will make use of the knowledge that most types of amino acids can exist in two different forms. One form is referred to as "left-handed" and the other as "right-handed." Just as the right hand on a human mirrors the left, these two forms of an amino acid mirror each other.
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