The first “wet chemistry” experiment conducted by NASA’s Curiosity rover may have found evidence of long-chain carboxylic acid, a fatty acid that could be the latest organic molecule to be discovered on Mars, researchers from the US space agency have revealed.
However, NASA scientist Daniel Glavin and his colleagues, who presented their findings at the 46th Lunar and Planetary Science Conference (LPSC) in Houston last week, caution that it is not possible at this time to determine whether or not the compound has a biological origin.
Contamination could also be to blame for the discovery, according to BBC News.
Does it answer the million dollar question?
The results were produced by Curiosity’s Sample Analysis at Mars (SAM) instrument suite, which analyzes organics and gases from both atmospheric and solid samples. SAM was created by NASA Goddard Space Flight Center, France’s Laboratoire Inter-Universitaire des Systèmes Atmosphériques (LISA), Honeybee Robotics and multiple other partner agencies.
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Glavin explained that the fatty acid was a good fit for one of the data peaks in a mudstone called Cumberland, the British news agency noted. A form of alcohol molecule could be among the compounds analyzed, and while the preliminary finding is exciting because fatty acids play a key role in the cell membranes of most types of living organisms (excluding microbes).
However, while he said that the research was “provocative” and that its link to potential life on Mars was the “million dollar question,” Glavin said that it was every bit as possible that the signal had a non-biological origin at this point. Another scientist commending on the study told the BBC that contamination also could not be rules out as a cause of the findings.
Mass spec-ing the Red Planet
The SAM team, which previously found evidence of chlorobenzene in the same rock, has also been working on a chemical leak in the instrument. That chemical, MTBSTFA, has actually helped their research, they explained, because they have used their understanding of how the organic molecule interacts with other compounds to discover organic substances on Mars.
The SAM instrument suite, which makes up more than half the science payload on the Mars Science Laboratory rover, features the same type of chemical equipment found in many Earth-based scientific laboratories, NASA said. It was created to search for compounds of the element carbon that are associated with life, and to figure out how they are created and destroyed in the Red Planet’s ecosphere.
Included among the instruments in the SAM suite are a mass spectrometer, gas chromatograph, and tunable laser spectrometer, they added. The mass spectrometer separates elements and compounds by mass for identification and measurement, while the gas chromatograph vaporizes soil and rock samples, separates the resulting gases into their components and analyzes them.
The laser spectrometer measures the abundance of carbon, hydrogen, and oxygen isotopes in atmospheric gases such as methane, water vapor, and carbon dioxide. Those measurements are accurate to within 10 parts per thousand, and since those compounds are vital to living things, their abundances are essential when evaluating the potential habitability of Mars.