Thanks to the microphone installed on the SuperCam instrument of the rover Perseverancescientists can listen March day by day. And it’s not just a great story of silence! Measuring winds, sound dispersion, atmospheric pressure, rover status, sounds on Mars help on a variety of topics.
But it’s true, the Jezero crater is a quiet site!
Not (too many) surprises
After having strongly participated in its design, then in its integration within the SuperCam instrumental suite, the French scientists (in an international team) published in the last issue of Nature a study of sounds recorded via a microphone on the Perseverance rover.
About fifteen French laboratories are taking part in the adventure, which remains a first: on previous missions sent to Mars, only InSight was equipped, but it only recorded infrasound… Converting into reality the vibrations of solar panels generated by weak Martian winds. Their first conclusion was expected, the winds are soft, very soft: on several occasions, the scientists thought it possible that the microphone was down!
Tic, tic, tic, tic makes the laser
Thanks to the mechanical sounds of the Perseverance mission (in particular those of its wheels, its drill and the impacts of its laser several meters away), the scientific team was able to very finely characterize the properties of the Martian atmosphere to propagate the sounds. As a result, the speed of sound on Mars changes according to the frequencies near the surface: 240 m/s for low frequencies below 240 Hz, and 250 m/s above!
If they could take a deep breath to talk to each other, two people would have trouble hearing each other 5 meters apart… However, low-pitched sounds can be heard from a distance with precision. During the 5 hours of recordings studied, the teams were able to distinctly recognize the sounds related to the flight of the Ingenuity helicopter, yet at a great distance.
Listen at doors
Finally, it should also be noted that in addition to characterizing Mars and its very fine variations in atmospheric density, temperatures and turbulence (winds, eddies), the microphone, as expected, allows us to learn a lot about the functioning of Perseverance himself!
A “stethoscope” of the mission? For the moment, its multiple cameras do the job very well, but for possible problems of propulsion, pumps or instruments, a microphone is not too much… For scientists who have studied the sounds of Perseverance, it It would be surprising if future missions did without such a small tool which can nevertheless provide a wide range of data.
Source: CNES
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