It's a small soundtrack, about ten seconds long, which, if it were taken out of its context, would probably not interest many people.
The document, however, is a scientific feat.
For the first time in history, humans have succeeded in directly capturing the sound of the wind blowing on another planet.
Mars in this case.
A recording released four days after the Perseverance robot landed on the Red Planet.
The announcement was made Monday by a member of NASA during a press conference.
If you missed this fun, you can click on the link below.
And listen a little.
This rover has been equipped with two types of microphones.
The first, the EDL microphone (Entry, Descent, Landing), was responsible for recording the sound of the terrible descent phase, during which the probe must go from a speed of more than 20,000 km / h to zero to put the robot down safely.
Unfortunately, due to interference, he could not achieve his goal.
"We would have loved to be able to watch the images of the Perseverance landing with sound, but that did not work," confirms Pernelle Bernardi, engineer at CNRS and technical manager of the Supercam instrument of the Perseverance rover.
NASA explained that the material was not the cause but that it was probably a problem of control.
"
Indeed, the JPL (Jet Propulsion Laboratory) teams ended up demonstrating that their microphone was indeed in working order.
Obviously wanting to share the very first Martian sound as quickly as possible with the general public, they attempted a new capture once the rover landed safely.
It is from these recordings that they were able to extract the famous ten-second sequence, and this first Martian wind heard all over the world.
It is this microphone which made it possible to capture the sound of the wind on March, broadcast on Monday.
NASA / JPL-Caltech
A second microphone designed in Toulouse
Perseverance undoubtedly has more beautiful surprises in store for us.
A second microphone, which was not foreseen when the project was launched, has in fact been integrated into the rover's “Supercam”, deployed at the top of its mast.
This is one of the most essential elements for the success of the mission.
And since showing a little chauvinism never hurts, it turns out that the microphone in question was developed in our regions, in Toulouse, on the Isae-Supaero side.
The teams of Pernelle Bernardi, technical manager of the Supercam, tried the day after landing to make the first recordings.
But the mast that supports the Supercam was then lying on Perseverance's back, which prevented convincing results from being obtained.
"We had a first sound on Saturday, but we felt that the interest was not sufficient to broadcast it," says David Mimoun, scientific manager of the microphone and professor at Isae-Supaero.
We'll do it when we have a nice thing.
And the nice thing could come quickly, since new data should arrive as early as Sunday morning.
This could suggest a new broadcast at the beginning of next week, hoping this time to be able to capture much more intensely the Martian environment, purged of the few pollution caused by the rover itself.
“The microphone, in this case, will be used to understand the Martian weather, listening to the winds.
Even though Mars has an atmosphere 100 times less dense than Earth, there is a lot of data to be exploited ”,
"Tac tac tac"
The interest of the tool is far from stopping at these considerations alone.
For scientists, it could even be huge.
To understand this, we must return to the very ambition of this mission, which must take place in two stages.
The little geological robot will take care of collecting the most interesting data possible, before they are brought back to Earth, for further analyzes, at the beginning of the year 2030. Scientists hope to recover traces of limestone and sediment, in the hope, eventually, of capturing a possible trace of Martian life.
To do this, the Supercam is equipped with a laser beam capable, from a distance, of vaporizing the rock at nearly 8000 degrees, in order to know its composition using a spectrometer.
"The microphone will bring us very interesting information," notes Pernelle Bernardi.
The vaporization of the rock will create a shock wave which emits a sound, a kind of very characteristic “tac tac tac” which will allow us to know the hardness of the rock.
Before the start of the mission, the French teams indeed multiplied the tests to “catalog” the sounds emitted during the vaporization of a particular rock.
The small microphone installed at the Supercam of the Perseverance rover.
Nasa / JPL
This work was notably carried out as part of his thesis by Baptiste Chide, alongside the teams of David Mimoun and those of Irap.
For the mission to be a success, the microphone has undergone a host of tests, for example by being subjected to nearly 1,500 cycles of temperature variations.
The climate on Mars is indeed far from welcoming, as temperatures can fluctuate by over 80 degrees between day and night.
“Space is a bit of haute-couture,” laughs David Mimoun.
We embed so-called traditional technologies but with a concern for extreme precision.
The idea is to master all the cogs of the tool perfectly, to know exactly what happens in the event of a problem.
"
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The microphone will also be useful for simply listening to the rover.
“These data could be interesting for NASA, continues Pernelle Bernardi.
By rotating the mast, we will be able to listen to how the robot behaves, how it works, to make sure that all is well ”.
And then, in these gloomy days, dreaming a little of the red planet probably doesn't hurt.
"It is important to bring good news, in full covid, wants to believe David Mimoun.
There has been a lot of criticism of French research, for example, lately.
But in space, the success is real.
We participated in the last three American missions in March.
The French are very good ”.
A little chauvinism, of course.