A team of researchers from Massachusetts Institute of Technology (MIT) has developed a technique that will help the 2020 Mars rover quickly and non-invasively identify sediments
on the Red Planet for signs of life. In 2020, NASA plans to launch a new Mars rover that will be tasked with probing a region of the planet that scientists believe could hold remnants of ancient microbial life.
“Such ‘pristine’ samples give scientists the best chance for identifying signs of former life, if they exist, as opposed to rocks whose histories have been wiped clean by geological processes such as excessive heating or radiation damage,” the study noted. The technique centres on a new way to interpret the results of Raman spectroscopy — a common, non-destructive process that geologists use to identify the chemical composition of ancient rocks.
According to Roger Summons, professor of earth, atmospheric and planetary sciences at MIT, the chemical picture that scientists have so far been able to discern using Raman spectroscopy has been somewhat fuzzy. “We don’t have a way to confidently distinguish between organic matter that was once biological in origin, versus organic matter that came from some other chemical process,” Summons noted in a paper reported in the journal Carbon.
However, Nicola Ferralis, research scientist in MIT’s department of materials science and engineering, discovered hidden features in Raman spectra that can give a more informed picture of a sample’s chemical makeup. Among its suite of scientific tools, the 2020 Mars rover includes SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals).
A Raman spectrum represents the vibration of a molecule or atom, in response to laser light. The improved technique enables scientists to more accurately interpret the meaning of existing Raman spectra, and quickly evaluate the ratio of hydrogen to carbon — thereby identifying the most pristine, ancient samples of rocks for further study. Ultimately, Summons said that in addition to identifying promising samples on Mars, the technique will help paleontologists understand Earth’s own biological evolution.
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