The Mars Perseverance rover records the first audio of a dust storm
Perseverance has captured the sound of dust grains impacting NASA’s rover, and the recording could be key to understanding how dust is transported around Mars.
The recording comes from a microphone in the perseverance vehicleThe ‘s SuperCam instrument on September 27, 2021, during the rover’s mission Sol 215. (A sun is a Martian day and about 40 minutes more than a day on Earth). Other instruments also detected the dust storm, which appears in images from Perseverance’s NavCam and in temperature and pressure measurements from Perseverance’s Mars Environmental Dynamics Analyzer (MEDA). Additionally, the scientists were able to use the microphone to accurately measure wind speed based on the sound intensity of the gusts.
The rover had already detected 90 dust eddies passing overhead, but this event marked the first time Perseverance had been lucky enough to have its microphone turned on at that time.
“With this dust swirl recording, we can listen and count the particles impacting the rover,” said Naomi Murdoch, a planetary scientist at the Institut Supérieur de l’Aéronautique et de l’Espace (ISAE–SUPAERO) at the University of Toulouse. in France and lead author of the study, told Space.com.
Related: Dust storm on Mars mysteries remain as scientists study the red planet
Taking everything into account—the audio recording, images, and temperature and pressure measurements—Murdoch and his colleagues determined that the dust storm was about 82 feet (25 meters) wide and at least 387 feet (118 meters) high. , and was moving at 17 feet (5.3 m) per second.
Based on the number of impacts, sound recordings quantified for the first time windblown dust grains in a dust storm. The recording includes a total of 308 impacts on the rover from dust grains carried by the winds of the dust swirl, and these impacts were distributed in three groups. The first cluster occurred as the rotating leading edge of the dust devil began to pass over Perseverance, and the third cluster occurred as the trailing edge reached the rover, with concentrations of dust on the vortex walls.
However, most of the impacts occurred as the vortex’s low-pressure center swirled over Perseverance, which was a disconcerting surprise.
Normally, one would expect most of the dust to be concentrated on the walls of the dust storm, where the wind speed is high. The center of a dust storm, like the eye of a storm, should, compared to the vortex walls, be relatively calm and clear.
However, in this particular dust eddy, there seemed to be a concentration of dust in the middle of the vortex. And the oddity was not a fluke in the recording as Perseverance’s NavCam also detected this internal dust.
“This particular dust eddy is unusual even for Mars,” Murdoch said. “We’re not entirely sure why the dust has accumulated in the center, but it may be because the dust eddy is still in its early stages of formation.”
the landing place of perseverance, crater lakeIt is located near one of the tracks of the great station dust storms and experiences a lot of dust swirls compared to Elysium Planitia, where NASA InSight lander landed in November 2018; that spacecraft has not detected a single dust eddy to date.
It’s not just atmospheric scientists who wish InSight had better luck with dust. The lander’s solar panels are now covered in too much dust to allow the mission continue much longer and in experience from previous missions, such as the Spirit and Opportunity rovers, dust eddies can blow dust from solar panels.
Previous work has shown that dust eddies and isolated gusts of wind are responsible for maintaining a significant amount of dust in the Martian atmosphere even outside of the dust storm season. However, the number of contributing dust eddies and the process by which they lift dust off the ground remains uncertain, so finding a dust eddy with this extra dust in the middle could be an important piece of the puzzle.
“We still don’t fully understand how, exactly, dust is lifted from the surface of Mars,” Murdoch said.
The findings illustrate the importance of the sonic environment as a new frontier for planetary scientists to explore.
Murdoch was part of the ISAE–SUPAERO team that designed and built the microphone for Perseverance’s SuperCam instrument, and it was always the intention to use it to try to listen for swirling dust. However, since each microphone recording session lasted only 167 seconds, the chances of the microphone turning on at the same time as a dust chute swept over the rover were low. But the slim chances didn’t deter Murdoch.
“Within our team at ISAE-SUPAERO we were convinced that a microphone on Mars would be an important instrument and we have not been disappointed,” he said.
The results are described in a paper published Tuesday (December 13) in Nature Communications.
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