How to Find Water in a Martian Rock Without Breaking It express
To find out if a Mars rock holds water without smashing it, scientists used neutron and X-ray scanning — similar to medical imaging. Neutrons pick up hydrogen, the foundation of water, allowing them to map moisture inside the sample. In the NWA 7034 meteorite, a chunk of Martian crust, scientists spotted minerals that look like rust but are soaked with water. These hydrogen-bearing iron oxides act like a stone sponge: they soaked up ancient water as it seeped into solidified lava. Even today, billions of years later, they hold moisture at temperatures above 100°C — water is locked not just as ice, but inside the rocks themselves. The Perseverance rover finds similar clues in Jezero Crater, hinting that early Mars was riddled with watery pockets. One day, this method could help study Martian samples on Earth without damaging a single grain, searching for microscopic traces of ancient life.
Original abstract
as written by the authors arXiv:2601.08390
The next great leap in Martian exploration will be the return of samples to Earth. To ensure the maximum scientific return from studying these samples, the development and utilisation of nondestructive analytical techniques are essential to enable early three-dimensional characterisation of their interiors. Neutron computed tomography is a powerful method in this context: it is highly sensitive to hydrogen and complements the more conventional X-ray computed tomography. Because the distribution and nature of hydrous phases are central to understanding the habitability, the climatic and geological evolution, and potential biosignatures of Mars, identifying hydrogenbearing phases in Martian crustal rocks is of particular importance. Using the only Martian crustal material available on Earth, the NWA 7034 meteorite and its pairs, we show that combined neutron and X-ray computed tomography enables non-destructive sample-wide mapping of hydrogen and reveals the distribution and petrographic contexts of hydrous phases. We identify hydrogen-rich iron oxyhydroxides within ancient igneous clasts, forming a macroscopic mineralogical water reservoir within the meteorite. These alteration assemblages closely resemble those observed in samples collected by the Perseverance rover in Jezero crater, where hydrated iron oxyhydroxides are also present. This similarity suggests that such phases may represent a widespread near-surface water reservoir on early Mars.
To 'squeeze' water out of such a stone sponge, you'd need temperatures above 400°C — heat you won't find on the Martian surface.
Like the hero of 'The Martian' extracting water from Martian soil, scientists are uncovering hidden moisture trapped in minerals.