The measurements, taken with the rover's PIXL and SHERLOC instruments, detected two categories of particles smaller than earlier Mars measurements had resolved: fine particles measuring less than 2.5 micrometers, and ultrafine particles around 100 nanometers, about 700 times thinner than a human hair. On PIXL's Teflon target and SHERLOC's Vectran swatch, dust averaged about 2 micrometers; on the basaltic glass and Teflon swatch, sizes ranged down to about 100 to 300 nanometers.
NASA sent the swatches, each three-quarters of an inch (20 millimeters) square, to Mars to study how spacesuit materials hold up on the planet's surface. Because Teflon contains no elements PIXL can directly detect, elemental signals from that sample come from dust resting on it. Static electricity appears to determine which dust sizes stick to which surface, and the finest particles stayed attached through years of driving and drilling. Organic polymers like Teflon, common in the outer layers of spacesuits, readily collect fine dust, though some materials hold less than others, a finding that could guide future material and coating choices. Designs such as suitports, which let astronauts enter a suit attached to the outside of a habitat, and dual-chamber airlocks could reduce how much dust reaches living quarters.
Dust has been a surface-exploration challenge since the Apollo program, when lunar dust scratched visors, degraded outer spacesuit layers and damaged seals, with some crew members reporting symptoms similar to hay fever. Martian dust grains, rounded by wind-driven collisions, are less abrasive than lunar dust and are enriched in sulfur, chlorine and iron, with more silica. Chemically, the dust measured by PIXL matches the iron- and sulfur-rich composition earlier missions found, and was enriched in phosphorus, with signs of calcium sulfate.
On Earth, airborne particles below 2.5 micrometers are tied to a range of negative health effects because they can penetrate deep into the lungs and enter the bloodstream; studies have shown ultrafine particles can travel from the nasal cavity to the brain along the olfactory nerve. Martian dust is composed predominantly of silicate minerals and carries chemically reactive compounds, including perchlorates that can disrupt thyroid function and reactive iron that induces cellular damage. Scientists believe the health risks depend on the quantity of dust and length of exposure.
Lindsay Hays, acting director of NASA's Planetary Science Division, said the agency has a history of turning challenges into workable solutions and of finding creative ways to use data to answer questions beyond what it was originally collected for. "Dust has been a surface-exploration challenge since the Apollo program," she said. "Perseverance is giving our engineers and flight surgeons measurements they can use to improve our existing designs well before the first American astronauts arrive on Mars."
Scott VanBommel, the paper's lead author and a Perseverance scientist at Washington University in St. Louis, said the existence of Mars dust at ultrafine sizes had been predicted for a long time, and PIXL gave the team the chance to measure it directly on Mars. "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."
Katie Stack Morgan, Perseverance's project scientist at NASA's Jet Propulsion Laboratory, noted the rover's main job is to search for signs of ancient microbial life, but the mission was also designed to help prepare for human explorers, including technology demonstrations and the spacesuit samples.
NASA is already testing solutions to extraterrestrial dust hazards, including an Electrodynamic Dust Shield that used electric fields to clear lunar regolith from glass and thermal radiator surfaces during a March 2025 mission to the Moon, and ground facilities testing spacesuit components ahead of Artemis missions.