Mars dust will be one of the most persistent hazards for the first astronauts on the Red Planet, and NASA’s Perseverance rover has now measured its smallest particles directly. Over 1,645 Martian days, the rover tracked fine and ultrafine dust clinging to samples of spacesuit material it carries, including particles small enough to reach the lungs and bloodstream.
The findings were published on 27 October in the Proceedings of the National Academy of Sciences. NASA’s Jet Propulsion Laboratory says they are the first on-site measurements of fine and ultrafine particles on Mars, and they could shape spacesuit and habitat design, dust-removal routines and crew health standards.
How Perseverance measured Mars dust on spacesuit samples
Perseverance carries five swatches of spacesuit material, each 20 millimeters square, on the calibration target for its SHERLOC instrument. NASA sent them to see how suit materials hold up on the surface. The team analyzed two of them, Teflon and Vectran.
The dust measurements came from PIXL, an X-ray instrument on the rover’s arm, whose own calibration target holds Teflon and basaltic glass. Teflon contains no elements PIXL can detect directly, so any elemental signal from that sample comes from the dust resting on it.
Earlier Mars measurements resolved particles down to about 3 micrometers. PIXL detected two smaller groups: fine particles under 2.5 micrometers and ultrafine particles around 100 nanometers, roughly 700 times thinner than a human hair. Particles on PIXL’s Teflon and SHERLOC’s Vectran averaged about 2 micrometers, while those on the basaltic glass and SHERLOC’s Teflon went down to about 100 to 300 nanometers.
Static electricity decides what sticks
According to JPL, static electricity appears to determine which particle sizes cling to which surfaces. Grains become charged as they collide in the air, and different materials attract different sizes. The finest particles stayed attached through years of driving and drilling.
“The larger clumps, the Martian dust bunnies, get shaken off over time,” said lead author Scott VanBommel of Washington University in St. Louis. “But the smallest particles stay behind, and those are the ones that pose the greatest challenge for human support systems.”
Chemically, the dust matches the iron- and sulfur-rich makeup seen by earlier missions. PIXL also found it enriched in phosphorus, with signs of calcium sulfate.
Why Mars dust matters for astronaut health
On Earth, fine particles below 2.5 micrometers are tied to health problems because they can penetrate deep into the lungs and enter the bloodstream. Studies have shown that ultrafine particles can travel from the nose to the brain along the olfactory nerve. Martian dust also carries perchlorates, which can disrupt thyroid function, and reactive iron that can damage cells. Scientists believe the risk depends on how much dust astronauts are exposed to and for how long.
The study found that some materials hold less dust than others, which could guide choices of materials and coatings. 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 gets indoors. NASA is also testing tools on the Moon, including an Electrodynamic Dust Shield that flew on Firefly Aerospace’s Blue Ghost Mission 1 in March 2025.
“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,” said Lindsay Hays, acting director of NASA’s Planetary Science Division.
I like that this result came from calibration targets, hardware meant mainly to tune instruments. For more Mars research, read about the Mars soil map that classifies 800 million sites and plasma technology for fueling a return trip from Mars.
FAQ
What did Perseverance find about Mars dust?
PIXL measured fine particles under 2.5 micrometers and ultrafine particles around 100 nanometers on spacesuit and calibration samples, the first such measurements made on Mars.
Is Mars dust toxic to astronauts?
It carries perchlorates that can disrupt thyroid function and reactive iron that can damage cells. Scientists believe the risk depends on how much dust astronauts inhale and for how long.
How could astronauts be protected from Mars dust?
Options include suit materials that hold less dust, suitports, dual-chamber airlocks and dust-removal tools such as NASA’s Electrodynamic Dust Shield.