FEATURE
The Story of Life…As Recorded in a Rock
The quest to discover whether Mars ever hosted an environment friendly to microscopic forms of life will begin with renewed vigor in 2010 when a Mini Cooper-sized robot touches down and begins scooping up, processing, and analyzing soil and rock samples to detect the presence of organic compounds.
Without question, the Mars Science Laboratory (MSL) will be one of the most complicated and capable missions ever landed on the surface of another planet, said Jennifer Eigenbrode, a biogeochemist who is working with the Goddard team building one of MSL’s onboard chemical-processing labs, the Sample Analysis at Mars (SAM) instrument suite.
SAM will carry out the initial search for organic compounds on Mars, relying on scorching heat to process the samples. SAM’s gas chromatograph and spectrometers will then analyze the resulting gases for potential biomarkers. “SAM should detect organic carbon if it is present, regardless of its chemistry,” Eigenbrode said.
| A Catch
But, there is a catch.
“Heat breaks carbon bonds, resulting in the loss of certain chemical information,” she said. “If SAM discovers an environment rich in organics, we will have compelling scientific reasons to develop more sophisticated tools that can determine if these are life or non-life processes. In that case, what we’ll need is a robotic laboratory that offers the capabilities and flexibility of an Earth-based organic geochemistry laboratory,” Eigenbrode said.
Achieving that next level of sophistication on a robotic laboratory operating millions of miles from home won’t be easy. But that’s what Eigenbrode has set out to do.
IRAD Funding to Develop Process
Using Internal Research and Development funding, Eigenbrode is now developing a chemical-processing method that would combine some of the many different steps researchers use in laboratories on Earth to process and study organic compounds to learn more about their evolution. “No single technology identifies all molecular components because they have different chemistries. If organics are present on Mars and elsewhere, they likely include complex compounds, which require additional processing to find them.” |
Goddard biogeochemist Jennifer Eigenbrode, who is an expert at detecting organic compounds in rocks, is using R&D funds to develop a simplified sample-processing method that could be applied to a robotic chemistry lab.
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Making her job more complex is the fact that such an in-line methodology doesn’t currently exist for Earth laboratories. Researchers must follow multiple steps when preparing samples for analysis. However, should Eigenbrode find the right combination of steps that could be applied easily to a next-generation instrument, NASA then would have the ability to identify a much larger variety of compounds and perhaps get a more complete picture of how life, if it existed in the first place, evolved over time, she said.
“We know that life interacts with its environment,” she said. Fossil fuels, after all, formed from prehistoric plants, animals, and microorganisms that died, decomposed into organic materials, and became buried under layers and layers of mud, rock, and sand 300 million years ago. “If life evolved here, it could have evolved elsewhere. What we want is a record of life and the most direct way to track these organisms is in the organic molecules in rock samples. What we need are the tools with which to do the search.”
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