Perseverance has given researchers their first direct look at Mars dust sizes on the surface, and the result reaches beyond geology. Scott VanBommel of Washington University in St. Louis and colleagues reported that particles in Jezero Crater are small enough to penetrate deep into human lungs and travel via the olfactory nerve to the brain.
The study, published in the Proceedings of the National Academy of Sciences, found the first direct in-situ evidence of dust at or below 2.5 micrometers and ultrafine particles at or below 100 nanometers. Those size classes matter for future astronauts because they are the kinds of particles crews would breathe, and the smallest can move past the body’s normal filters.
PIXL dust maps in Jezero Crater
Researchers drew on PIXL elemental fluorescence maps and optical images from SHERLOC's WATSON camera to locate individual dust particles and infer their sizes. PIXL used a flat calibration target of Teflon and polished basaltic glass to check its X-ray fluorescence performance each day, and that target collected dust over 1,645 Martian sols of operation in Jezero Crater.
That span gave the team a long record of dust accumulation under Mars conditions. The target was designed to show that PIXL was producing accurate elemental maps of Mars rocks, so the same hardware used to calibrate the instrument also became the dust record the researchers analyzed.
Teflon and Vectran
The team cross-checked the target with 10 small spacesuit material swatches, each measuring 20 mm by 20 mm, or 0.79 by 0.79 inches. The swatches included Teflon and Vectran, and the two materials did not collect the same mixture of particles. Instead, they sorted Martian dust by size.
Vectran is an aromatic polyester-polyamide fiber used in suit construction, and the study used that difference to test how material choice changes what gets picked up. The same Martian dust supply, captured over the same 1,645-sol period, produced different size patterns on Teflon and Vectran, which means a protective layer can change what particles are carried toward habitats.
Scott VanBommel study
Scott VanBommel and his coauthors left one practical question open: how the measured dust levels would affect astronaut health during a real Mars mission. The study shows the particles are there and identifies the sizes, but mission planning still has to account for how crews and suit materials would interact with that dust once people arrive on Mars.
