Ar-Rehman

Building blocks of life found by NASA's Curiosity rover on Mars

NASA’s Curiosity Mars rover has been dutifully probing Gale crater and Mount Sharp since the robot plopped down on the Red Planet on 06 August, 2012. But there’s new news from the car-sized Mars machinery now wheeling about in the Glen Torridon region of Gale crater, a place that scientists believe was a locale where ancient conditions would have been favorable to supporting life, if it was there in the first place. NASA's Curiosity rover has found a diverse mix of organic molecules on Mars, including chemicals considered building blocks for the origin of life on Earth. The discovery from a rock sample Curiosity drilled in 2020 possessed the largest variety of organic molecules ever found on the Red Planet. When scientists studied the sample, they found 21 different carbon-containing molecules, seven of which had never been seen on Mars before. Curiosity's Sample Analysis at Mars (SAM) is a suite of instruments built to search for compounds of the element carbon that are associated with life. NASA's Curiosity Mars rover found a diverse mix of organic molecules including chemicals widely considered building blocks for the origin of life on Earth. The finding marks the first time a new kind of chemical experiment has been performed on another planet.

Curiosity rover, car-sized Mars rover is now wheeling about in the Glen Torridon region of Gale crater, a place that scientists believe could have supported conditions which were favorable to supporting ancient life, if it was ever there in the first place. While in the region, Curiosity recently utilized its onboard Sample Analysis at Mars (SAM) instrument suite, built to search for compounds of the element carbon that are associated with life and investigate ways in which these compounds are generated and destroyed in the Martian ecosphere. Curiosity's SAM instrument was able to use a chemical known as tetramethylammonium hydroxide (TMAH) to detect organic molecules in the region's clay-rich sandstone. The newly identified chemicals include nitrogen and sulfur-bearing molecules which are similar to the raw material that helped spur life on Earth. However, the experiment can't tell if the chemicals come from ancient Martian life or non-biological geological processes. The study of Curiosity's first SAM TMAH experiment was led by Amy Williams, an associate professor in the Department of Geological Sciences at the University of Florida in Gainesville. The research has been published in the journal Nature Communications. Organic molecules are important because they are the basic chemical building blocks needed for life. While researchers say this discovery does not 100% prove that life existed on Mars, they said these molecules can be created through natural chemical or geological processes. And their presence shows that ancient Mars had the right chemistry to potentially support living organisms. The rock sample 'Mary Anning 3' was collected from the slopes of Mount Sharp, and billions of years ago, this area likely had lakes and streams.

"This experiment and its results have been a labor of love and science," Williams said. "This was the first time that TMAH had been used on another world and our team worked extensively to interpret and confirm the molecules detected in this first-of-its-kind experiment." Mars beckons for future life detection missions and instruments. Humans and robots are likely to team up to augment the types of exploration avenues which can be done on the Red Planet. Curiosity has found a diverse mix of organic molecules on Mars. The finding marks the first time a new kind of chemical experiment has been performed on another planet. Curiosity's experiment detected more than 20 organic molecules from clay-bearing sandstones in the roughly 3.5-billion-year-old Knockfarrill Hill section of Glen Torridon. The variety of organic molecules observed suggests that some chemical diversity has been preserved in ancient Martian sediments despite billions of years of diagenesis (the process by which sediment turns to rock) and radiation exposure. "We propose that this suite of organics represents TMAH thermochemolysis breakdown products from ancient organic macromolecular material that has been preserved in billions-of-years-old sedimentary rocks in Gale crater," explains the research paper. Williams said the rover's discoveries were confirmed with other instruments aboard. "We iterated on molecule identifications using some of the SAM flight spare equipment to confirm our findings," Williams said. "I think the time was well spent, as we now have evidence that the suite of molecules broken apart by the TMAH reagent derived from more complex macromolecular carbon that is preserved in the martian subsurface."

The NASA Curiosity rover finding confirms that ancient Mars had the right chemistry to support life. One of the most interesting discoveries in the rock was a nitrogen heterocycle, a type of molecule which contains carbon and nitrogen arranged in a ring. These structures are important because they can be early building blocks of RNA and DNA, the molecules which carry genetic information in living things. “That detection is pretty profound because these structures can be chemical precursors to more complex nitrogen-bearing molecules,” said Amy Williams. When scientists studied the sample, they found 21 different carbon-containing molecules, seven of which had never been seen on Mars before. Mars machinery has detected more than 20 organic molecules from clay-bearing sandstones in Glen Torridon, Gale crater, work done by the Sample Analysis at Mars instrument suite onboard the Curiosity rover. The newly-issued paper explains that the ongoing characterization of organic matter on Mars "is a pillar of modern robotic exploration, as space agencies send rovers and landers to explore Mars' past and present habitability and to search for signs of life." Furthermore, within a decade of time, researchers have advanced from the search for organic molecules on Mars to identifying native Martian organics. "We are now poised to address the source of these organics, whether exogenous (e.g., meteoritic, cometary, or interplanetary dust particles) or endogenous (e.g., abiotically or biologically produced)," Williams and colleagues report in the study. As noted, the confirmation of macromolecular organic matter "supports the possibility that future optimized TMAH thermochemolysis experiments can liberate ancient biosignatures preserved in macromolecules on Mars (if present)." The results of the SAM TMAH experiment "expand the library of confirmed and suggested organic molecules preserved over deep geologic time in the Martian near-surface and confirm the presence of macromolecular carbon on Mars," the paper concludes.

“Nitrogen heterocycles have never been found before on the Martian surface or confirmed in Martian meteorites. We think we're looking at organic matter that's been preserved on Mars for 3.5 billion years," Williams added. "It's really useful to have evidence that ancient organic matter is preserved, because that is a way to assess the habitability of an environment. And if we want to search for evidence of life in the form of preserved organic carbon, this demonstrates it's possible." Another molecule discovered was benzothiophene, which contains carbon and sulfur. This compound has also been found in meteorites and scientists believe meteorites may have helped spread the chemicals needed for life throughout the early solar system. “This is Curiosity and our team at their best. It took dozens of scientists and engineers to locate this site, drill the sample, and make these discoveries with our awesome robot,” said the mission’s project scientist, Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Southern California. “This collection of organic molecules once again increases the prospect that Mars offered a home for life in the ancient past.” The scientists say that Curiosity's discoveries could tie into observations from NASA's other on-duty Mars rover. "Our findings are aligned with some observations of organic matter with the Perseverance rover," Williams said. The TMAH experiment on Curiosity was used to identify cyclic (or aromatic) organic compounds that derived from more complex macromolecular carbon, Williams said. Meanwhile, the Perseverance rover has used a different instrument to find evidence for both cyclic organic compounds and macromolecular carbon. "We now have evidence for diverse and potentially complex organic matter, preserved in different locations on Mars and detected with different instrument suites. This suggests that organic carbon is better preserved over long time periods on Mars than we expected, given the harsh radiation environment," Williams said.

It’s the first time a new kind of chemical experiment has been performed on Mars, with researchers publishing their results in the journal Nature Communications. Can Ozempic change your mind? Dr. Drew breaks down ‘Ozempic personality’. Scientists believe the Torridon region of the Gale crater could have supported conditions favorable to supporting ancient life, if any such life ever existed on the red planet. Curiosity used its onboard Sample Analysis at Mars instruments to search for compounds of carbon associated with life and investigate how those compounds are generated and destroyed on Mars. Curiosity was able to identify chemicals, including nitrogen and sulfur-bearing molecules, in the clay-rich sandstone of the region. These new results could be useful for future life detection instruments done robotically or by astronauts, Williams said, calling the TMAH experiment a "trailblazer for upcoming planetary missions." Versions of the TMAH experiment are flying with the Mars Organic Molecule Analyzer (MOMA) on the European Space Agency's Rosalind Franklin rover destined for Mars' Oxia Planum plain, and on the Dragonfly Mass Spectrometer (DraMS) instrument being installed on the Dragonfly rotorcraft destined for Saturn's moon Titan. Williams said that the new results can help inform the experimental design for these future missions.

"The TMAH experiment revealed that macromolecular carbon is preserved over long time periods in some of the rocks on Mars. This is powerful information for future life detection missions and instruments, as we now know that larger molecules that could have been made by life can be preserved in the Martian near surface," Williams added. Next generation instruments can focus on techniques to more fully extract these organics and glean new information about their identity and potentially their origin, be it geologic, meteoritic, or biologic. However, the experiment isn’t able to definitively determine whether the chemicals come from geological processes or ancient Martian life. Researchers also say the findings aligned with findings from the Mars Perseverance rover, providing evidence for potential organic matter preserved in different locations.