Hear the weather on Mars recorded by Perseverance rover
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A towering whirlwind of dust 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 devil using his microphone.
Dust devils, or dust whirlwinds, 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 the NASA InSight lander has even captured seismic and magnetic signals created by the dust devils. But sound has been the missing element so far.
When the Perseverance rover landed on Mars in February 2021, it became the first mission to take microphones on a journey to the red planet.
The robot explorer’s SuperCam microphone happened to be on and recording on Sept. 27, 2021, when a dust devil passed directly over the rover, according to a new study published Tuesday in the journal Nature communication.
During an 11-second clip captured by the microphone, there are two periods of low-frequency wind as the dust devil’s front and rear walls pass over the rover, said lead study author Dr. Naomi Murdoch, researcher at the University of Toulouse’s Higher Institute of Aeronautics and Astronautics.
Between the walls of the whirlwind is a quiet period when the rover was in the eye of the whirlwind, Murdoch said.
Crackles and hisses can be heard during the event, which were determined to be dust particles hitting the rover.
The researchers were able to count the particles in the dust devil as they hit the rover, leading to an entirely new type of measurement on the red planet, Murdoch said. It is the first time an instrument has been able to quantify elevated dust on Mars.
Images and other data sent back by the rover also confirmed what happened. When the researchers put together all the elements collected by the rover, they determined that the dust devil was more than 118 meters high and spanned 25 meters wide – about 10 times larger than the rover itself. While this sounds like a huge whirlwind, it’s the average size for Martian dust devils, Murdoch said.
The researchers were surprised to find that dust accumulated inside the dust devil, rather than just being carried within the outer walls — possibly because the dust devil may have been still forming when it moved over Perseverance.
Dust devils serve as indicators of atmospheric turbulence on Mars and play an important role in the Martian dust cycle.
Learning more about how dust is uplifted and moves on the red planet — an important feature of the weather and climate, as dust is the most important feature — can help scientists understand the formation and evolution of dust storms.
A planet-encircling dust storm is what ended the Opportunity rover’s 15-year mission in 2018.
“Global dust storms are important to understanding the Martian climate,” Murdoch said. “The acoustic measurements of dust impacts and dust lifts will therefore improve our understanding of dust devils and also help to improve Martian climate models. Understanding dust lifting is also critical to space missions because of the damage that can be done to hardware.
Perseverance’s wind sensors have already been damaged by uplifted dust particles likely carried by wind or a dust devil, Murdoch said.
Dust devils have a reputation for being both helpful and harmful on Mars.
The The InSight lander mission is expected to end this month after four years of studying earthquakes and other phenomena on the red planet. Layers of dust have accumulated on the solar panels, preventing the spacecraft from accumulating enough power to continue using its instruments.
Dust devils are common in Jezero Crater, where Perseverance landed, but they seem to be absent from InSight’s home in the flat plain of Elysium Planitia – and researchers aren’t exactly sure why.
“In the case of InSight, the dust from the atmosphere has settled on the solar panels. However, because there are no whirlwinds capable of lifting dust in the InSight region, the whirlwinds cannot ‘clean’ the solar panels.”
Other Mars missions have even benefited from regular cleanings by dust devils, which acted as vacuum cleaners for the dust collected on the solar-powered Spirit and Opportunity rovers and gave them longer-than-expected lifespans.
The Higher Institute of Aeronautics and Space of the University of Toulouse, known as ISAE SUPAERO, built the microphone that sits on Perseverance. Every month, Murdoch and her team gather eight shots of approximately 167 seconds each.
“We estimate that a single mid-day microphone sighting (the time of day when there is the most dust devil activity) has only a 1 in 200 chance of picking up a dust devil like the one we encountered,” Murdoch said. “We definitely got lucky, but we also carefully targeted the instrument observations to increase the chance of success.”
More microphone recordings could capture additional dust devils, and Murdoch’s team uses acoustic recordings to measure atmospheric turbulence to determine range on Mars.
The SuperCam microphone was originally included to listen as instruments on the rover’s zap rocks determine their properties, but the acoustic data also sheds light on the atmospheric science possibilities on the red planet, Murdoch said.
“All of these measurements and analyzes show how valuable acoustic data is in planetary exploration. Therefore, at ISAE-SUPAERO, we are simultaneously developing the next generation of acoustic sensors that will be sent to other planetary bodies with an atmosphere in the future,” she said.
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