A peer-reviewed study published on September 8, 2026, estimates that exposed water ice at six sites around Mars’s north pole generally contains less than 3% dust by mass. Earlier estimates reached about 25%. The result applies to exposed ice at locations poleward of 65°N. The study in npj Space Exploration presents a revised estimate based on spectral observations and a model of layered ice.
How researchers estimated the dust
Pari Mohan and Aditya R. Khuller analyzed visible and near-infrared observations from OMEGA aboard Mars Express and CRISM aboard Mars Reconnaissance Orbiter, along with albedo measurements from the Phoenix lander site. Albedo is the proportion of incoming light a surface reflects.
The researchers used a radiative-transfer model to estimate how light moves through layers of ice and impurities. It combines Mie theory with a modified Delta-Eddington method, and its best fits typically use a surface layer and a subsurface layer. The deeper modeled layer is set at 20 meters to represent an optically thick layer.
The model generally treats dust particles as separate from ice grains. If the impurities are inside the grains instead, the paper says their actual amount would be about half the modeled estimate.
Dusty marker beds are a different layer
The study separately describes marker beds 1 to 20 meters thick, with estimated dust fractions of 10–50% by volume, equivalent to 24–74% by mass. Those concentrated layers are distinct from the exposed ice-rich material behind the generally lower estimate.
The distinction matters because dust, ice-grain size, layering and seasonal frost all affect how polar ice reflects sunlight and exchanges energy. The revised estimates can help constrain models of Mars’s polar energy balance, ice stability and climate evolution.
What the findings say about life
Aditya R. Khuller has discussed a possible analogy between dusty Martian meltwater and microbial meltwater pools on Earth. That is a hypothesis about potential habitats, not a life detection; the study examines ice properties and climate. Khuller discussed the analogy in an interview with Space.
