If life ever existed on Mars, traces of it could still be preserved beneath the planet’s icy surface. Recent experiments conducted by NASA and Penn State University suggest that fragments of biomolecules from ancient microbes may survive in Martian ice for tens of millions of years. Laboratory simulations exposed frozen samples of E. coli to Martian temperatures and radiation levels equivalent to 50 million years on the Red Planet. The results indicate that pure ice, unlike ice mixed with soil, can act as a protective time capsule for biological molecules, offering a promising target for future missions searching for signs of past. life.
Testing life’s survival in Mars conditions
To explore how biomolecules endure on Mars, scientists froze bacteria in both pure water ice and ice combined with Martian soil analogs, including silicate-based rocks and clay. Samples were cooled to minus 51 degrees Celsius, mirroring the temperature of icy Martian regions, and exposed to radiation levels simulating millions of years on the planet. Researchers found that amino acids, the building blocks of proteins, survived far longer in pure ice than in soil-containing ice. In pure ice, more than 10% of the original amino acids remained intact after the simulated exposure, whereas those mixed with soil degraded almost completely.The study suggests that in pure ice, radiation byproducts such as free radicals become trapped and immobilized, slowing the chemical breakdown of biomolecules. In contrast, minerals in Martian soil may create microenvironments that accelerate molecular damage. This difference highlights why ice-dominated regions on Mars are considered prime locations for preserving biological material and searching for signs of ancient life.
Lessons from Earth’s extreme environments
The experiments also tested even colder temperatures similar to those on icy moons like Europa and Enceladus. Findings showed that lower temperatures further reduce the rate of biomolecule deterioration, suggesting that icy environments across the solar system could preserve traces of life for extended periods. This has significant implications for astrobiology and the search for extraterrestrial life beyond Mars.
What this means for future missions
“These results suggest that pure ice or ice-dominated regions are ideal places to look for recent biological material on Mars,” said Alexander Pavlov, lead author and NASA space scientist. With upcoming missions planned to explore Martian polar regions, researchers hope to use these findings to guide landing sites and sampling strategies. The study emphasizes that ice is not just a frozen landscape but potentially a biological archive waiting to be explored.
