On September 27, 2021, a large dust vortex swept past Perseverance. The rover didn’t only capture the weather on its cameras and weather sensors, but also captured the faint sound of the storm and its dusty noise on its microphone. This is the first time the rover has recorded the sounds on Mars.
A swarm of dust (the smell of smoke in French, so often called stutterd rain) is a phenomenon that humans like to understand. The Mars Pathfinder mission first recorded it in the 1970s. Dust vortices on the red planet can be dozens of times larger than Earth’s (the dust vortex that recently was discovered by Perseverance was 25 meters wide and 118 meters high a mid-level storm from Martian descent).
A dust storm captured by the navigation camera of the Perseverance rover. The color scale is a bit thin, with the lowest dust content (blue) and the highest amount of yellow. Image: NASA
In their study of Mars for decades, a Rover can be seen with camera, spectrograph and weather sensors so humanity can take better picture of a red planet, as well as the environment, it does today. The sound is being added to the list. This combination of data will allow researchers to understand the nature of dust whirlwinds and their impact on the future robotic and crewed missions.
In the 2000s, a man thought long-term storms could disrupt research instruments on Mars, making them useless. Yet, 20 years of practice have proved that long-term phenomena on the contrary can be useful, including cleaning of solar panels from sand that accumulates on them.
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Dust swirls are caused by the conditions of the atmosphere that are characteristic of Mars.
There must be very large temperature gradients between the ground and the air. Earth is warming, and air is warming. The air flow slowly rises, the elements around rotate and the vortex movement is observable, says Naomi Murdoch of the University of Toulouse, the author of this article in Nature Communications.
There are many offend questions to keep in mind how this is going. It’s a real advantage in Lake Ezero-Crater, where Perseverance is now located, the dust devils are everywhere, and in Elysian Plain, where the InSight lander is located, the rare ones are available. It’s obvious!
The problem, which we have now has is not predicted, says Naomi Murdoch.
The researchers believe that it’s the microphone, which was first used on Mars, which will help figure it out. The NASA website lists that two spacecraft that shipped microphones to Mars failed, and the other one didn’t turn on its instrument.
The amplitude of the instrument is significant when the wind is strong enough. It’s all that if you’re talking on the telephone in the wind. We use this background noise to study the wind on Mars.
Perseverance has many other tools that require time to work. The microphone window usually takes several minutes. The researchers planned them during the afternoon, when atmospheric events are most active. There were only eight windows in a month; therefore, not only careful planning, but also a good portion of luck helped the researchers to catch the Martian dust devil.
The microphone detected large impact sounds. Individual grains that touched the area around the Perseverance instrument made noticeable thumps. By counting these collisions, the researchers can see how dense these particles were in the dust vortexesmeasurements that no other instrument could take and which could explain how dust vortices lift particles from the surface. Dust devil data spectrogram showing low frequency wind noise, high-frequency impacts of large sand particles and rover pump sounds at 760 Hz. Image: N. Murdoch/ISAE-SUPAERO.
This study is just one of the early examples of the use of acoustic data in planetary exploration. In the future, instruments can collect data with a high sampling rate, and allow you to observe rapid change of events like wind gusts. Unlike sensors, timescales are many seconds the distance.
We’ve got the best sample rate on earth! It’s a bit like using a microscope. Scientists say we are looking at what happens in such a short time.
NASA provides a playlist with sounds recorded on Mars from the sound of the wind to the sound of the rover.
Our microphone has the same bandwidth as the human ear, so it isn’t regulated in any way. These are the sounds you could hear if you were standing on earth. And it’s so cool, says Murdoch.