NASA's Perseverance rover carries, in addition to cameras and sensors, small patches of spacesuit material - each less than 6.5 square centimeters in area. They are needed to assess how Martian dust affects future astronaut suits. This is reported in a new study published in the journal Proceedings of the National Academy of Sciences (PNAS).
"Mars is a very dusty place," noted lead author Scott VanBommel of Washington University in St. Louis. "Astronauts heading there will have to be prepared."
Scientists compared Martian dust with lunar dust. During the Apollo missions, abrasive particles scratched helmet visors and damaged spacesuits, and on returning to the module the dust got into the air and caused astronauts to experience symptoms similar to hay fever. The new data indicate that Martian dust may be less dangerous: after 1,645 Martian sols (roughly the same number of Earth days), the patches showed almost no visible damage.
On closer inspection, the particles from Mars turned out to be much smoother than the jagged grains from the Moon. "Particles in the Martian atmosphere could have been rolled by wind for billions of years, so they are well rounded, like pebbles in a river," VanBommel explained. This means they scratch equipment less and irritate the lungs less.
However, there is another problem: Martian dust can be extremely fine. VanBommel developed a method for estimating the size of each particle. Some of them turned out to be ultrafine - only about 100 nanometers across (one ten-thousandth of a millimeter). On Earth, such particles from smoke and polluted air pose a serious health threat, as they penetrate deep into the lungs and enter the blood. Astronauts will not breathe the Martian atmosphere directly, but engineers will have to take these microscopic risks into account when designing habitat modules, spacesuits and air filtration systems.
In addition, data from the PIXL instrument (Planetary Instrument for X-ray Lithochemistry) made it possible to analyze the chemical composition of the particles. Unlike lunar dust, Martian dust contains perchlorates and other potentially toxic compounds, and is also enriched in sulfur, iron and silicon. Short-term exposure is unlikely to seriously harm health - much depends on the dose and duration - but these substances add another risk factor for mission planners.
The authors emphasize: rovers have been operating on the surface of Mars for more than 20 years, and dust remains a challenge, but it is possible to prepare for it. The study was observational in nature and did not test the effect of dust on humans directly.