NASA’s Perseverance rover has identified ultrafine dust particles on Mars, marking the smallest dust measurements recorded on the planet to date. Operating in and around Jezero Crater in Mars’ northern hemisphere since its 2021 landing, the rover detected particles as small as approximately 100 nanometers in diameter, roughly 500 times thinner than a human hair.

Mars is known for its dusty environment, with dust circulated by regular winds, dust devils, and dust storms ranging from local to global scales. Understanding the characteristics of this dust is critical for future human missions, as the particles may pose health risks and affect equipment durability.

Scott VanBommel, a planetary scientist at Washington University in St. Louis and lead author of the study detailing the findings in the journal Proceedings of the National Academy of Sciences, emphasized that smaller dust particles have a greater potential to penetrate deeply into the human respiratory system and can be harder to clear from the body. Martian dust contains hazardous substances such as silica, iron compounds, and chlorine-based chemicals like perchlorate. While the toxicity depends on exposure levels, these components are known to be harmful in sufficient doses on Earth.

Prior to this, measurements of Martian dust resolved particles down to about 3 micrometers in diameter. Perseverance’s Planetary Instrument for X-ray Lithochemistry (PIXL) revealed two finer categories: ultrafine particles near 100 nanometers and fine particles less than 2.5 micrometers across, approximately 30 times thinner than a human hair.

These tiny particles raise concerns not only for astronaut health—due to their ability to infiltrate lungs and potentially enter the bloodstream—but also for the longevity of spacesuits and habitats. The rover carries small samples of spacesuit materials such as Vectran fiber and Teflon coating to assess their interaction with Martian dust. Vectran, about 20 millimeters square, tended to accumulate larger dust particles, particularly on the underside of its weave, while the Teflon samples held fewer but finer particles. These differences likely stem from the materials’ varying electrostatic properties.

VanBommel noted that while the dust adhered differently to the materials, there is no current evidence that the dust caused damage. The findings provide valuable insights into the challenges of protecting human explorers and equipment from pervasive Martian dust in future missions.