Perseverance has captured the sound of dust grains impacting the NASA rover, and the recording may very well be key to understanding how dust is transported round Mars.
The recording comes from a microphone on the Perseverance rover‘s SuperCam instrument on Sept. 27, 2021, throughout sol 215 of the rover’s mission. (A sol is a Martian day and about 40 minutes longer than a day on Earth.) Different devices additionally detected the dust satan, which options in pictures from Perseverance’s NavCam and temperature and strain measurements from Perseverance’s Mars Environmental Dynamics Analyzer (MEDA). Plus, the scientists have been ready to make use of the microphone to precisely measure wind speeds primarily based on the depth of the sound of the gusts.
The rover had already detected 90 dust devils passing overhead, however this occasion was the primary time Perseverance was lucky sufficient to have its microphone switched on on the time.
“With this dust-devil recording, we are able to really hear and rely particles impacting the rover,” Naomi Murdoch, a planetary scientist on the Institut Supérieur de l’Aéronautique et de l’Espace (ISAE–SUPAERO) on the College of Toulouse in France and lead writer of the examine, instructed Area.com.
Associated: Mars dust storm mysteries remain as scientists study the Red Planet
Taking every thing under consideration — the audio recording, the pictures, and the temperature and strain measurements — Murdoch and her colleagues decided that the dust satan was about 82 toes (25 meters) throughout and at the least 387 toes (118 m) tall, transferring at 17 toes (5.3 m) per second.
Based mostly on the variety of impacts, the sound recordings quantified for the primary time ever the wind-blown dust grains in a dust satan. The recording features a total of 308 impacts on the rover from dust grains carried by the winds of the dust satan, and these impacts have been distributed in three bunches. The primary group occurred when the whirling vanguard of the dust satan began passing over Perseverance, and the third group got here when the trailing edge reached the rover, with concentrations of dust within the partitions of the vortex.
Nevertheless, probably the most impacts by far occurred when the low-pressure heart of the vortex was swirling above Perseverance, which got here as a puzzling shock.
Ordinarily, one would count on many of the dust to be concentrated within the partitions of the dust satan, the place the wind speeds are excessive. The middle of a dust satan, like the attention of a storm, ought to, compared to the vortex’s partitions, be comparatively calm and clear.
On this specific dust satan, nonetheless, there gave the impression to be a focus of dust in the course of the vortex. And the oddity wasn’t a fluke within the recording since Perseverance’s NavCam additionally noticed this inside dust.
“This specific dust satan is uncommon even for Mars,” Murdoch mentioned. “We aren’t solely certain why the dust has collected within the heart, however it could be as a result of the dust satan remains to be in its preliminary phase of formation.”
Perseverance’s touchdown web site, Jezero Crater, lies close to one of many tracks of the large seasonal dust storms and experiences an abundance of dust devils in comparison with Elysium Planitia, the place NASA’s InSight lander touched down in November 2018; that spacecraft hasn’t detected a single dust satan thus far.
It is not simply atmospheric scientists who want InSight had higher dust satan luck. The lander’s solar panels at the moment are lined in an excessive amount of dust to allow the mission to continue much longer and within the expertise of earlier missions such because the Spirit and Alternative rovers, dust devils can blow dust from solar arrays.
Earlier work has proven that dust devils and remoted wind gusts are chargeable for sustaining a significant amount of dust within the Martian environment even exterior of dust-storm season. But how a lot dust devils contribute and the method by which they loft the dust off the bottom stays unsure, which is why discovering a dust satan with this additional dust within the center may very well be an essential piece of the jigsaw.
“We nonetheless don’t absolutely perceive how, precisely, dust is lifted from the floor of Mars,” Murdoch mentioned.
The findings illustrate the significance of the sonic atmosphere as a brand new frontier for planetary scientists to discover.
Murdoch was a part of the staff at ISAE–SUPAERO who designed and constructed the microphone for Perseverance’s SuperCam instrument, and the intention was all the time to make use of it to attempt to hear dust devils. Nevertheless, with every microphone recording session lasting solely 167 seconds, the percentages have been low that the microphone can be switched on on the identical time a dust satan swept over the rover. However the slim possibilities didn’t dissuade Murdoch.
“Inside our staff at ISAE–SUPAERO we have been satisfied {that a} microphone on Mars can be an essential instrument, and we have not been disenchanted,” she mentioned.
The outcomes are described in a paper printed Tuesday (Dec. 13) in Nature Communications.
Observe Keith Cooper on Twitter @21stCenturySETI. Observe us on Twitter @Spacedotcom and on Facebook.
