Perseverance finds ultrafine Mars dust clinging to spacesuit materials

NASA's Perseverance rover has measured fine and ultrafine Martian dust stuck to samples of spacesuit material it carries, including particles small enough to reach deep into human lungs, NASA said on October 26, 2026. The study, led by Scott VanBommel of Washington University in St. Louis, appears in the Proceedings of the National Academy of Sciences (PNAS). NASA describes the results as the first on-site measurements of fine and ultrafine particles on Mars.

What the rover measured

The data span 1,645 Martian days. The measurements came from PIXL, the Planetary Instrument for X-ray Lithochemistry, looking at its own calibration target, which holds a sample of Teflon and one of basaltic glass. PIXL cannot directly detect any of the elements that make up Teflon, so any elements it measures there belong to dust lying on the sample.

The team also studied Teflon and Vectran swatches on the calibration target of SHERLOC, an instrument on the rover's robotic arm. That target carries five samples of spacesuit material, each 20 millimeters (three-quarters of an inch) square, which NASA sent to Mars to see how suit materials hold up on the surface.

The paper's abstract reports particles as small as 100 to 200 nanometers on spacesuit samples and calibration targets. It describes the dust as a mafic silicate enriched in phosphorus, iron and sulfur, which matches the iron- and sulfur-rich composition measured by earlier missions. PIXL also detected signs of calcium sulfate.

Static electricity appears to decide what sticks

NASA says static electricity seems to be what sorts the dust. Grains pick up an electric charge when they bump into each other in the air, and each material on the target pulls in particles of a different size. Years of driving and drilling knocked the larger clumps loose, but the finest grains stayed put. Teflon and similar organic polymers, which are common in the outer layers of spacesuits, gathered fine dust readily, while some other materials held less.

The larger clumps, the Martian dust bunnies, get shaken off over time. But the smallest particles stay behind, and those are the ones that pose the greatest challenge for human support systems.

Why it matters for astronauts

NASA notes that on Earth, airborne particles under 2.5 micrometers are linked to a range of harmful health effects, because they can reach deep into the lungs and pass into the blood. Studies have also found that ultrafine particles can move from the nasal cavity to the brain along the olfactory nerve. Martian dust also contains perchlorates, which can interfere with the thyroid, and reactive iron, which can damage cells.

Dust has caused trouble before. On the Apollo missions, Moon dust scratched visors, wore down the outer layers of spacesuits and damaged their seals, and some astronauts reported hay fever-like symptoms. Mars dust grains are rounder and less abrasive than the Moon's, but richer in sulfur, chlorine and iron, and dust storms can keep them circulating through the atmosphere.

What the study does not show

The measurements do not say how much dust a crew would breathe, or set safe limits. NASA says scientists think the health risk from Mars dust depends on how much of it people are exposed to, and for how long. The data come from a handful of material samples on a single rover, and the links between fine particles and health come from research on Earth.

What comes next

NASA says the results can feed into work on indoor dust-exposure limits for astronauts, safe working habits and methods for clearing dust on Mars. Because some materials hold less dust than others, the findings could also inform which materials and protective coatings are used for suits and habitats. NASA points to designs that could keep dust out of living quarters, such as suitports, where an astronaut climbs into a suit fixed to the outside of a habitat, and airlocks with two chambers.

The agency is already testing dust defenses on the Moon and on the ground. In March 2025, an Electrodynamic Dust Shield that uses electric fields cleared lunar soil from glass and radiator surfaces after landing aboard Firefly Aerospace's Blue Ghost Mission 1. For how journal papers like this one differ from preprints, see how peer review works.