NASA’s Curiosity rover - fitted with Air Liquide technology - has found new evidence preserved in rocks on Mars that suggests the planet could have supported ancient life, as well as new evidence in the Martian atmosphere that relates to the search for current life on the Red Planet.
While not necessarily evidence of life itself, these findings are a good sign for future missions exploring the planet’s surface and subsurface.
Curiosity has found ‘tough’ organic molecules in three-billion-year-old sedimentary rocks near the surface, as well as seasonal variations in the levels of methane (CH4) in the atmosphere.
Organic molecules contain carbon and hydrogen (H2), and also may include oxygen (O2), nitrogen (N2) and other elements. While commonly associated with life, organic molecules also can be created by non-biological processes and are not necessarily indicators of life.
“With these new findings, Mars is telling us to stay the course and keep searching for evidence of life,” said Thomas Zurbuchen, Associate Administrator for the Science Mission Directorate at NASA Headquarters, Washington. “I’m confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the Red Planet.”
“Curiosity has not determined the source of the organic molecules,” said Jen Eigenbrode of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who is lead author of one of the two new Science papers. “Whether it holds a record of ancient life, was food for life, or has existed in the absence of life, organic matter in Martian materials holds chemical clues to planetary conditions and processes.”
Although the surface of Mars is inhospitable today, there is clear evidence that in the distant past, the Martian climate allowed liquid water – an essential ingredient for life as we know it – to pool at the surface. Data from Curiosity reveal that billions of years ago, a water lake inside Gale Crater held all the ingredients necessary for life, including chemical building blocks and energy sources.
“The Martian surface is exposed to radiation from space. Both radiation and harsh chemicals break down organic matter,” said Eigenbrode. “Finding ancient organic molecules in the top five centimetres of rock that was deposited when Mars may have been habitable, bodes well for us to learn the story of organic molecules on Mars with future missions that will drill deeper.”
Finding organic molecules
To identify organic material in the Martian soil, Curiosity drilled into sedimentary rocks known as mudstone from four areas in Gale Crater. This mudstone gradually formed billions of years ago from silt that accumulated at the bottom of the ancient lake. The rock samples were analysed by Curiosity’s Sample Analysis at Mars (SAM) which uses an oven to heat the samples (in excess of 900 degrees Fahrenheit, or 500 degrees Celsius) to release organic molecules from the powdered rock.
SAM measured small organic molecules that came off the mudstone sample – fragments of larger organic molecules that don’t vaporize easily.
The results also indicate organic carbon concentrations on the order of 10 parts per million or more. This is close to the amount observed in Martian meteorites and about 100 times greater than prior detections of organic carbon on Mars’ surface. Some of the molecules identified include thiophenes, benzene, toluene, and small carbon chains, such as propane or butene.
In 2013, SAM detected some organic molecules containing chlorine in rocks at the deepest point in the crater. This new discovery builds on the inventory of molecules detected in the ancient lake sediments on Mars and helps explains why they were preserved.
Finding methane in the atmosphere and ancient carbon preserved on the surface gives scientists confidence that NASA’s Mars 2020 rover and ESA’s (European Space Agency’s) ExoMars rover will find even more organics, both on the surface and in the shallow subsurface.
These results also inform scientists’ decisions as they work to find answers to questions concerning the possibility of life on Mars.
Air Liquide: part of the project
The Tier One company was tasked with installing the SAM chromatograph’s capillary tubes, which is used to separate Martian molecules before they are analysed by Curiosity’s instruments. Air Liquide’s unique micro-brazing and micro- soldering expertise, developed on its site on Sassenage, France, that enabled the company to be part of the Curiosity project.
In particular, a technique for crimping the capillary tubes before brazing was developed to meet the requirements of the space industry. Air Liquide’s technician, Dominique Chazot, assembled the final parts of the chromatograph on NASA’s site in Washington. This required extraordinarily fine solders, with unparalleled precision.
The ExoMars programme will be launched in 2020 to look for other traces of life on Mars.
As with Curiosity, Air Liquide has been tasked with assembling the capillary tubes for the chromatograph in the mission’s main instrument, the MOMA (Mars Organic Molecule Analyser), which was developed by LISA (Inter-University Laboratory for Atmospheric Systems) to detect biological activity. This work, carried out in an ISO5 clean room, is all the more painstaking because the MOMA must be sterile in order to avoid contaminating any potential life on the planet.
As part of the ExoMars project, Air Liquide’s team’s skills were also called on for other parts of the robot: Bistable On/Off valves, real switches between the chromatograph’s different columns, a storage tank, and micro-regulation valves to manage the helium (He) (the gas used by the chromatograph), heated tubes to maintain samples at the correct temperature, derivatisation cells containing the products required for the analyses, and more.
The teams were able to adapt the technologies and processes to meet the constraints of sterility and decontamination.
Air Liquide is a major contributor to space exploration for more than 50 years. The Group takes part in the largest international projects, including the European Ariane launcher program, satellite programs (primarily Herschel, Planck and MeteoSat Third Generation) and the International Space Station (with the MELFI cold storage system).
For more information visit https://www.advancedtech.airliquide.com.