Perseverance's dust data: what clings to spacesuit materials on Mars

Perseverance has directly measured Martian dust grains as small as about 100 nanometres. These grains stuck to calibration hardware that has ridden on the rover for years. According to NASA, the rover measured fine and ultrafine dust over 1,645 Martian days, including particles small enough to penetrate the lungs and enter the bloodstream. The work is due in the Proceedings of the National Academy of Sciences on 27 October. This article relies on NASA's release and earlier conference abstracts from the same team. I could not retrieve the PNAS paper itself, so finer details of its method and statistics are not covered here.

The data are not a simulation of suit wear. They are an accidental, passive exposure test: dust settled on a vertical plate and on fabric swatches, and stayed there through driving and drilling. That makes them useful for design, and it also limits what they can show.

01A dust sensor made from a blank puck

The key measurement comes from PIXL, the X-ray fluorescence spectrometer on the rover's arm. Its calibration target carries a sample of Teflon and a sample of basaltic glass. The Teflon puck is the useful part. PTFE is built from carbon and fluorine, and, as the team has written in conference abstracts, it contains no elements PIXL can directly detect through XRF, so interrogating it on Mars essentially assesses the dust directly. An earlier abstract makes the same point: apart from the rhodium anode lines, characteristic X-rays in the PTFE spectra are effectively due to accumulated dust.

So a component meant to confirm that the X-ray source and detector work became a dust collector with a known blank background. The team's work has treated the dust as a thin layer. In the abstract's wording, a thin sample limits the analysis to excitation by the incident X-ray flux alone. The abstract also notes that signals from thin dust on an XRF-invisible substrate skew toward low-energy, low-atomic-number elements. Any volume or thickness estimate has to correct for that bias. The abstracts do not say how the final paper handles it.

The second data stream comes from SHERLOC, the Raman and fluorescence instrument. Its calibration target carries suit materials on purpose. The bottom row holds a polycarbonate helmet-visor piece, Vectran (a cut-resistant glove-palm fabric), Ortho-Fabric, and two kinds of Teflon. The paper analysed the Teflon and Vectran swatches. NASA says the swatches were sent to study how spacesuit materials hold up on the planet's surface. The SHERLOC team did not originally set out to build a suit-materials experiment. A team member said they first wanted a Teflon reference and materials with good Raman signatures, and the suit-materials role grew from there.

02What the numbers say

Earlier Mars measurements resolved dust only down to about 3 micrometres. PIXL separated two smaller categories: fine particles under 2.5 micrometres and ultrafine particles around 100 nanometres. NASA's comparison is that a human hair is about 70 µm wide, so a 100 nm grain is roughly 700 times thinner.

Grain size depended on the surface, as the table shows.

Particles on PIXL's Teflon and SHERLOC's Vectran averaged about 2 micrometres, while PIXL's basaltic glass and SHERLOC's Teflon held dust down to roughly 100 to 300 nanometres. The same bare polymer therefore held very different populations depending on where it sat and which instrument looked at it. The release does not explain this, and the full paper may.

Composition matches earlier missions' iron- and sulfur-rich dust. PIXL also found enrichment in phosphorus and signs of calcium sulfate. A 2024 Mars-conference abstract from the team already pointed to phosphorus enrichment and electrostatic effects on the calibration target. The PNAS paper appears to build on that work.

03Electrostatics sets what sticks

The central mechanism is electrostatic. NASA says static electricity appears to determine which dust sizes stick to which surface: grains charge as they collide in the air, and different calibration-target materials attract different sizes. Two consequences follow.

• Persistence. The finest particles stayed attached through years of driving and drilling. Lead author Scott VanBommel of Washington University in St. Louis said larger clumps shake off over time while the smallest grains remain. He called these the hardest challenge for human support systems.
• Polymer vulnerability. NASA says organic polymers like SHERLOC's Teflon sample are common in suit outer layers and readily collect fine dust. This matters because Teflon is often chosen for its nonstick, dust-repelling properties. The result shows that low adhesion to large grains does not guarantee low adhesion to submicron grains.

The study also found that some materials hold less dust than others. NASA presents this as a basis for choosing materials and protective coatings for suits and habitats. The release gives no ranking or quantitative retention figures, so engineers will need the paper's tables.

04Why Mars dust is a different problem from lunar dust

NASA's framing starts from Apollo, when lunar dust scratched visors, degraded outer suit layers and damaged seals. Mars dust differs. Wind-driven collisions have rounded its grains, so they are less abrasive than lunar ones. Martian dust is also richer in sulfur, chlorine and iron, and it has more silica. Regional and global storms keep it circulating.

This shifts the design priorities. Abrasion and mechanical wear matter less on Mars. Respiratory and chemical exposure matter more. On Earth, particulate matter below 2.5 µm is linked to health effects because it reaches deep into the lungs and the bloodstream. Studies have shown ultrafine particles can travel from the nasal cavity to the brain along the olfactory nerve. Martian dust is mostly silicate minerals, and it carries reactive compounds such as perchlorates, which can disrupt thyroid function, and reactive iron, which induces cellular damage. NASA says scientists believe the risk depends on dose and exposure time. That is why measured size distributions feed directly into indoor exposure limits.

05From measurement to mitigation, and what is unproven

NASA names several mitigation routes that follow from this. Suitports, which let astronauts enter a suit attached to the outside of a habitat, and dual-chamber airlocks could reduce how much dust enters living quarters. The research could also inform exposure limits, dust-handling routines and removal methods.

Active dust removal is being tested on the Moon. In March 2025, an Electrodynamic Dust Shield from Kennedy Space Center flew on Firefly's Blue Ghost Mission 1. It used electric fields to clear regolith from glass and thermal-radiator surfaces. At Johnson Space Center, engineers use vacuum chambers and lunar simulant to test suit components and a handheld electrostatic dust-mitigation tool ahead of Artemis. Electrostatics here is both the cause of the adhesion and a possible way to remove the dust. Whether that approach works on 100 nm Martian grains at Mars pressures is not established by these data.

The limits of the dataset are worth stating plainly:

• The swatches are small, passive and mounted on a rover. They are not flexed or abraded, and no suit pressure or seal is involved.
• The exposure is a single site history. It covers Jezero crater and its dust-raising events along the traverse.
• The data show size and adhesion. They do not give toxicity, and the release gives no exposure thresholds.
• Material rankings need laboratory confirmation with Mars-analogue dust under representative humidity, charge and pressure.

Even so, these are the first on-site measurements of fine and ultrafine particles on Mars. They give suit and habitat designers a measured size range, and a mechanism to test against, before any crew arrives. Katie Stack Morgan, Perseverance project scientist at JPL, noted that the spacesuit swatches belong to the mission's human-exploration preparation. The next steps are the paper's material-by-material data and laboratory tests that reproduce the electrostatic conditions behind them.