Measurement of dust devils’ range on Mars using acoustic microscopic recordings of atmospheric wind and air turbulence
More microphone recordings could capture additional dust devils, and Murdoch’s team is using acoustic recordings to measure atmospheric turbulence to determine its range on Mars.
The microphone picked up data about the wind conditions and also detected small impacts that were striking the area around it, making a ping. By counting each of these impacts, the researchers could see how dense these particles were within the dust devil — a measurement that no other instrument has been able to take and that could help to model how dust devils lift particles from the surface.
Dust devils occur because of atmospheric conditions on Mars. “You have to have a really large temperature gradient between the ground and the air,” Murdoch explained. The air rises because the ground gets warm and then the air starts to rise. The rotation of things starts when the air starts to rise.
The researchers were surprised to find that the dust devil still had some dust in it even after moving over Perseverance.
Understanding more about how dust moves on the red planet can help scientists better understand the evolution of dust storms, which are a key feature of its weather and climate.
Dust removal from the solar panels of the InSight lander and implications for acoustic-based Mars detection systems: The Case of the JZ Crater
The InSight lander’s mission is expected to end this month after spending four years studying quakes and other phenomenon on the red planet. Layers of dust have collected on its solar panels and prevented the spacecraft from collecting enough power to continue operating its instruments.
There are a lot of unanswered questions regarding how dust can be lifted off the surface, thanks to the forces of wind shear and dust devils. Dust devils are a common occurrence in the Jezero Crater where Perseverance is located, but it’s not clear why they aren’t more frequent in Elysium Planitia.
“In the case of InSight, the dust has settled out of the atmosphere onto the solar panels. However, because there are no whirlwinds capable of lifting dust in the region of InSight, the whirlwinds are not able to ‘clean’ the solar panels.”
Dust devils have been used in previous Mars missions to clean up the dust collected on the rovers, and have given the missions longer lifespans.
The University of Toulouse’s Higher Institute of Aeronautics and Space, known as ISAE-SUPAERO, built the microphone that sits on Perseverance. Every month, Murdoch and her team collect eight recordings lasting about 167 seconds each.
Murdoch said that there was a very small chance of recording a dust devil like the one they encountered. We definitely got lucky, but we also carefully focused the observations to raise our chances of success.
Naomi Murdoch of the University of Toulouse was one of the authors of the paper about the research, and she said they were convinced that the microphone would give them new information about Mars. We haven’t been disappointed.
“All of these measurements and analyses highlight just how valuable acoustic data are in planetary exploration. Therefore, in parallel, at ISAE-SUPAERO, we are developing the next generation of acoustic sensors that will be sent to other planetary bodies with an atmosphere in the future,” she said.
That is where the microphone comes in. The wind speed is sensitive to the microphone’s sensitivity. When it is windy, a large amount of sound on the microphone will increase, like when you are talking on the phone. “We’re using that background noise to study the wind.”
Our microphone bandwidth is the same as the human ear, and so we don’t have to change the sounds we hear. Murdoch said they are the sounds that you would hear if you were on another planet. “And that’s really cool.”