Martian Ice: Best Hope for Finding Life on Mars, New Study Suggests
Mars Ice Could Preserve Evidence of Ancient Life for Millions of Years, New Study Finds
Future missions to Mars may need to prioritize drilling into ice deposits rather than focusing on rocks and soil, according to a new study from NASA and Penn State. Researchers have found that key building blocks of proteins can survive for tens of millions of years when trapped in Martian ice, offering a potential time capsule for evidence of past life on the Red Planet. The findings, published in the journal Astrobiology, significantly shift the understanding of where to look for biosignatures on Mars.
The research team, led by Alexander Pavlov of NASA Goddard Space Flight Center and including Christopher House of Penn State, recreated Martian conditions in the laboratory to test the survivability of organic molecules. They sealed fragments of amino acids from E. Coli bacteria within test tubes filled with pure water ice, and in other samples, combined the bacteria with materials mimicking Martian sediment – silicate-based rocks, and clay. The samples were then subjected to intense gamma radiation, simulating decades of cosmic ray bombardment.
“Fifty million years is far greater than the expected age for some current surface ice deposits on Mars, which are often less than two million years old,” explained Professor House, affiliate of the Huck Institutes of the Life Sciences and the Earth and Environment Systems Institute, and director of the Penn State Consortium for Planetary and Exoplanetary Science and Technology. “That means if there are bacteria near the surface of Mars, future missions can find it.”
Simulating the Martian Environment
The laboratory setup meticulously mirrored the harsh conditions on Mars. Samples were frozen to minus 60 degrees Fahrenheit, matching temperatures found in icy regions of the planet. The radiation chamber exposed the samples to the equivalent of 20 million years of cosmic ray exposure, and then an additional 30 million years was modeled, bringing the total simulated exposure to 50 million years. After irradiation, the samples were shipped back to NASA Goddard for amino acid testing.
Pure Ice Offers Superior Protection
The results were striking. In the pure water ice samples, over 10 percent of the amino acids – the fundamental components of proteins – remained intact after the full 50 million year simulation. However, samples mixed with Martian sediment degraded ten times faster and showed significantly reduced survival rates. This difference highlights the protective qualities of pure ice.
This finding reverses some previous assumptions. A 2022 study by the same team showed that amino acids in a mixture of 10% water ice and 90% Martian soil broke down more quickly than samples containing only sediment. “Based on the 2022 study findings, it was thought that organic material in ice or water alone would be destroyed even more rapidly than the 10% water mixture,” Pavlov said. “So, it was surprising to find that the organic materials placed in water ice alone are destroyed at a much slower rate than the samples containing water and soil.”
Researchers theorize that the accelerated degradation in mixed samples is due to a thin film forming where the ice contacts the minerals. This layer could facilitate radiation movement, increasing damage to the amino acids. “While in solid ice, harmful particles created by radiation get frozen in place and may not be able to reach organic compounds,” Pavlov explained. “These results suggest that pure ice or ice-dominated regions are an ideal place to look for recent biological material on Mars.”
Implications Beyond Mars
The implications of this research extend beyond the search for life on Mars. The team also tested organic material at temperatures similar to those found on Europa, a moon of Jupiter, and Enceladus, a moon of Saturn. At these even colder temperatures, the rate of deterioration slowed down further, suggesting that the icy moons could also harbor preserved biosignatures.
These findings are particularly encouraging for NASA’s -launched Europa Clipper mission, which is scheduled to reach Jupiter in . The mission will conduct numerous close flybys of Europa to assess the habitability of its subsurface ocean.
Accessing Buried Ice on Mars
Successfully searching for life in Martian ice will require the right tools and techniques. The NASA Mars Phoenix mission was the first to excavate and photograph ice in the Martian Arctic, demonstrating the feasibility of accessing subsurface ice.
“There is a lot of ice on Mars, but most of it is just below the surface,” House said. “Future missions need a large enough drill or a powerful scoop to access it, similar to the design and capabilities of Phoenix.”
The research team included Zhidan Zhang, Hannah McLain, Kendra Farnsworth, Daniel Glavin, Jamie Elsila, and Jason Dworkin. The work was funded by NASA’s Planetary Science Division Internal Scientist Funding Program.