A new NASA study indicates that traces of ancient life on Mars could survive for over 50 million years in pure ice, protected from cosmic radiation. Researchers recommend future missions focus on drilling into clean ice deposits rather than rocks or soil. The findings, based on lab simulations, highlight pure ice as a potential preserve for organic material.
Scientists at NASA Goddard Space Flight Center and Penn State have conducted experiments simulating Martian conditions to assess the preservation of organic material in ice. The study, published in Astrobiology, tested amino acids derived from E. coli bacteria sealed in pure water ice and in mixtures with Martian-like sediments such as silicate-based rocks and clay.
Samples were frozen at minus 60 degrees Fahrenheit and exposed to gamma radiation equivalent to 20 million years of cosmic rays on Mars, with an additional 30 years modeled, totaling 50 million years. In pure water ice, more than 10 percent of the amino acids survived intact. However, when mixed with sediments, the organic material degraded 10 times faster.
"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, meaning any organic life present within the ice would be preserved," said co-author Christopher House, a geosciences professor at Penn State.
Lead researcher Alexander Pavlov noted the surprise in the results: "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." The team attributes the protection in pure ice to harmful radiation particles being frozen in place, unable to reach the compounds.
A prior 2022 study by the same group showed faster destruction in a 10 percent water ice and 90 percent soil mix. The findings extend to colder environments like Jupiter's moon Europa and Saturn's moon Enceladus, supporting NASA's Europa Clipper mission, launched in 2024 and set to arrive in 2030 for 49 flybys.
For Mars, accessing subsurface ice will require advanced drilling, similar to the 2008 Phoenix mission, which photographed ice near the Martian Arctic. "There is a lot of ice on Mars, but most of it is just below the surface," House added. "Future missions need a large enough drill or a powerful scoop to access it."
The research was funded by NASA's Planetary Science Division and involved team members including Hannah McLain, Kendra Farnsworth, Daniel Glavin, Jamie Elsila, Jason Dworkin, and Zhidan Zhang.