This is what Martian dust devils sound like…

The Mars rover Perseverance is equipped with the first working microphone on the planet’s surface. It has been used to record the first audio of an extraterrestrial whirlwind. This marks a significant milestone in our understanding of the Martian environment.

Planetary scientist Naomi Murdoch and colleagues from the National Higher French Institute of Aeronautics and Space and NASA published their findings in Nature Communications. Roger Wiens, professor at Purdue University, leads the team behind the discovery. . He is in charge of Perseverance’s SuperCam, a collection of sensors that make up the rover’s “head” and include sophisticated remote-sensing equipment with a variety of spectrometers, cameras, and the microphone.

“We can learn a lot more using sound than we can with some of the other tools,” Wiens adds. “They take readings at regular intervals. The microphone lets us sample, not quite at the speed of sound, but nearly 100,000 times a second. It helps us get a stronger sense of what Mars is like.”

The microphone doesn’t stay on all the time; it only records for about three minutes every few days. Wiens said that getting the whirlwind recording was lucky, but it wasn’t completely out of the blue. Since Perseverance’s landing in the Jezero Crater, the crew has found evidence of roughly 100 dust devils there—tiny dust and grit tornadoes. The microphone was turned on for the first time when one flew over the rover.

Together with observations of air pressure and time-lapse imagery, the sound recording of the dust devil helps scientists better comprehend the atmosphere and weather of Mars.

“We could watch the pressure drop, listen to the wind, then have a little bit of silence that is the eye of the tiny storm, and then hear the wind again and watch the pressure rise,” Wiens adds. It took seconds. “The wind is fast — about 25 miles per hour, but about what you would see in a dust devil on Earth. The difference is that the air pressure on Mars is so much lower that the winds, while just as fast, push with about 1% of the pressure the same speed of wind would have back on Earth. It’s not a powerful wind, but clearly enough to loft particles of grit into the air to make a dust devil.”

The data suggest that future astronauts won’t have to worry about antennae or habitats being blown down by gale-force winds, meaning that no future Mark Watneys will be left behind. Other rovers, notably Opportunity and Spirit, may have lasted longer due to winds clearing dirt off their solar panels.

“Those rover teams would see a slow decline in power over a number of days to weeks, then a jump. That was when wind cleared off the solar panels,” according to Wiens.

It’s possible that the absence of wind and dust devils in the area of Elysium Planitia where the InSight mission landed is a contributing factor to the fact that the mission is coming to an end.

“Just like Earth, there is different weather in different areas on Mars,” Wiens remarks. “Using all of our instruments and tools, especially the microphone, helps us get a concrete sense of what it would be like to be on Mars.”

Source: 10.1038/s41467-022-35100-z

Image / Audio Credit:  NASA/JPL-Caltech/LANL/CNES/CNRS/ISAE-SUPAERO