ExoMars rover will search for evidence of life on Mars
Artist’s impression of the ExoMars rover and surface platform on the surface of Mars. Image Credit: ESA/ATG medialab
An international team of scientists has developed a toaster oven-sized chemistry lab for a robotic rover that will drill up to two meters (about 6 1/2 feet) beneath the Martian surface in search of evidence of present or past life on the Red Planet. The laboratory, called the Mars Organic Molecule analyzer (MOMA), is a crucial instrument for the ExoMars Rover, a joint mission between the European Space Agency (ESA) and the Russian space agency Roscosmos. Scientists at NASA’s Goddard Space Flight Center are making a significant contribution to the MOMA instrument. The ExoMars mission is scheduled to launch to Mars in July 2020.
“The ExoMars Rover’s two-meter deep drill will provide MOMA with unique samples that may contain complex organic compounds preserved from an ancient era, when life might have gotten started on Mars,” said MOMA Project Scientist Will Brinckerhoff of NASA’s Goddard Space Flight Center via a release.
While the surface of Mars is currently inhospitable to known forms of life, there is evidence that in the distant past, liquid water was present on the Red Planet’s surface. NASA’s Mars rovers, including Opportunity and Curiosity which are still actively exploring the Red Planet, have found additional signs of past habitable environments.
MOMA should be capable of detecting and identifying a wide variety of organic compounds. These compounds contain hydrogen and carbon and can also include oxygen, nitrogen and other elements. While organic compounds are commonly associated with life, they can also be created by non-biological processes. To fit MOMA into the ExoMars rover, scientists had to shrink instruments that would normally occupy a couple of lab benches – down to the size of a toaster oven.
Precision assembly and mechanical technician Ryan Wilkinson inspects MOMA during thermal vacuum testing at Goddard. Photo Credit: NASA
MOMA is built around a single, very small mass spectrometer that separates charged atoms an molecules by mass. The process for finding organic compounds on Mars can be broken down into two steps: separating the rocks and sediment and giving them an electric charge (ionized) so that they can be detected and identified by the mass spectrometer. The first step uses an oven to bake the sample, vaporizing the organic molecules and sending them to a thin column that separates mixtures of compounds into their individual constituents. The compounds then sequentially pass into the mass spectrometer, where they are given an electrical charge and sorted using electrical fields.
MOMA has a second method for finding larger organic molecules that are fragile and would be broken apart during the vaporization process. MOMA zaps them with a with a quick burst of laser light, vaporizing the molecules without totally breaking them apart. The laser also gives these molecules an electrical charge, sending them directly from the sample to the mass spectrometer where they are sorted and identified.
Chirality, or handedness, is a property of certain organic molecules that may provide a hint that they were created by life. Some organic molecules used by life come in two varieties that are mirror images of each other. Life on Earth uses left-handed amino acids and all right-handed sugars to build larger molecules, such as proteins from amino acids and DNA from sugars.
The MOMA instrument is capable of determining the chirality of organic molecules. If it finds that a particular organic molecule is primarily of the right- or left-hand variety, called “homochirality,” that could be evidence that the molecule was produced by life, because non-biological processes tend to make an equal mix of varieties. Life based on right-handed amino acids and left-handed sugars could work, but a mix of right- and left-handed for either could not. This is because these molecule need to come together in the correct orientation, like puzzle pieces, to build the larger molecules necessary for life to function.
MOMA recently completed pre-delivery reviews by both ESA and NASA. On Wednesday, May 16, 2018 the MOMA team gathered at Goddard to see off their science instrument on the first step of its journey to the Red Planet: delivery to Thales Alenia Space, in Turin, Italy, where it will be integrated into the rover’s analytical laboratory drawer this summer. Following later rover and spacecraft-level integration activities in 2019, the ExoMars Rover is scheduled to launch to Mars in July, 2020 atop a Proton-M launch vehicle from the Baikonur Cosmodrome in Kazakhstan.
Video courtesy of NASA’s Goddard Space Flight Center/Dan Gallagher
Jim Sharkey
Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.
