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A mighty dust eddy passed right over the Perseverance rover as it explored the site of an ancient lake on Mars, and the rover recorded the first sounds of this Martian dust eddy. using his microphone.
Dust eddies, or dust eddies, are common on Mars and are part of the red planet’s weather patterns.
Other missions have collected images, weather data, and dust measurements from these events, and NASA’s InSight lander even recorded seismic and magnetic signals created by the dust eddies. But sound has been the missing element, until now.
When the Perseverance rover touched down on Mars in February 2021, it became the first mission to carry microphones on a trip to the red planet.
The robotic rover’s SuperCam microphone was turned on and recording on Sept. 27, 2021, when a dust storm passed directly over the rover, according to a new study published Tuesday in the journal. nature communications.
During an 11-second clip captured by the microphone, there are two periods of low-frequency wind as the front and rear walls of the dust eddy pass over the rover, said study lead author Dr. Naomi Murdoch, a researcher of the Higher Institute of Aeronautics and Space of the University of Toulouse.
Between the walls of the eddy is a period of calm when the rover was in the eye of the vortex, Murdoch said.
Crackling and hissing sounds can be heard during the event, which were determined to be dust grains hitting the rover.
The researchers were able to count the particles in the dust vortex as they hit the rover, leading to an entirely new type of measurement on the red planet, Murdoch said. It is the first time that an instrument has been able to quantify the rising dust on Mars.
Images and other data sent back by the rover also confirmed what happened. When the researchers put together all the items collected by the rover, they determined that the dust storm was more than 387 feet (118 meters) tall and 82 feet (25 meters) wide, about 10 times larger than the rover itself. While this sounds like a massive whirlwind, it is about the average size for Martian dust eddies, Murdoch said.
The researchers were surprised to find that the dust was accumulating within the dust storm, rather than simply being transported within the outer walls, possibly because the dust storm may still have been in the process of forming as it moved over Perseverance.
Dust eddies serve as indicators of turbulence in the Martian atmosphere and play an important role in the Martian dust cycle.
Learning more about how dust rises and moves on the red planet, a key feature of its weather and climate, since dust is its primary feature, may help scientists better understand the formation and evolution of storms. dust.
A dust storm encircling the planet is what Opportunity rover’s 15-year mission ended in 2018.
“Global dust storms are important to understanding Martian climate,” Murdoch said. “Acoustic measurements of dust impacts and dust lift will therefore improve our understanding of dust eddies and also help improve Martian climate models. Understanding dust lift is also critical for space missions because to the damage that can be caused to the hardware”.
Perseverance’s wind sensors have already been damaged by overhead dust particles likely carried by the wind or a dust storm, Murdoch said.
Dust eddies have a reputation for being both helpful and harmful on Mars.
the The InSight lander mission is expected to end this month After spending four years studying earthquakes and other phenomena on the red planet. Dust layers built up on its solar panels and prevented the spacecraft from collecting enough power to continue operating its instruments.
Dust eddies occur frequently in Jezero crater, where Perseverance landed, but they appear to be absent from InSight’s home on the plain of Elysium Planitia, and researchers aren’t sure why.
“In the case of InSight, dust from the atmosphere has settled on the solar panels. However, because there are no eddies capable of kicking up dust in the InSight region, eddies cannot ‘clean’ the solar panels.”
In fact, other Mars missions have benefited from regular cleanups by dust eddies, which acted as vacuum cleaners for dust accumulated on the solar-powered Spirit and Opportunity rovers, giving them longer-than-expected lifespans. expected.
The Higher Institute of Aeronautics and Space of the University of Toulouse, known as ISAE-SUPAERO, built the microphone that sits on top of Perseverance. Every month, Murdoch and his team collect eight recordings of about 167 seconds each.
“We estimate that a single microphone observation in the midday period (the time of day when there is the greatest dust-eddy activity) has only a 1 in 200 chance of recording a dust-eddy like the one we found,” he said. Murdoch. “We definitely got lucky, but we also carefully focused the instrument’s observations to increase the chances of success.”
More microphone recordings could capture additional dust eddies, and Murdoch’s team is using acoustic recordings to measure atmospheric turbulence to determine its range on Mars.
The SuperCam microphone was originally included for listening as instruments on the rover zap rocks to determine their properties, but its acoustic data also sheds light on the possibilities for atmospheric science on the red planet, Murdoch said.
“All these measurements and analyzes highlight how valuable acoustic data is in planetary exploration. For this reason, in parallel, at ISAE-SUPAERO we are developing the next generation of acoustic sensors that in the future will be sent to other planetary bodies with an atmosphere”, he said.
