A towering whirlwind of dust passed right over the Perseverance rover as it explored the site of an ancient lake on Mars – and the rover recorded the first sounds of this Martian dust devil using its microphone.
Dust devils, or dust whirlwinds, are common on Mars, and they’re part of the weather patterns on the red planet.
Other missions have gathered images, weather data and dust measurements of these events, and the NASA InSight lander even recorded seismic and magnetic signals created by the dust devils. But sound has been the missing element — until now.
When the Perseverance rover landed on Mars in February 2021, it became the first mission to carry microphones on a journey to the red planet.
The robotic explorer’s SuperCam microphone just happened to be turned on and recording on September 27, 2021, when a dust devil passed directly over the rover, according to a new study published Tuesday in the journal Nature Communications.
During an 11-second clip captured by the microphone, there are two periods of low frequency wind as the leading and trailing walls of the dust devil pass over the rover, said lead study author Dr. Naomi Murdoch, researcher at the University of Toulouse’s Higher Institute of Aeronautics and Space.
In between the walls of the whirlwind is a calm period when the rover was in the eye of the vortex, Murdoch said.
Crackling and hissing can be heard during the event, which were determined to be dust grains hitting the rover.
The researchers were able to count the particles in the dust devil as they hit the rover, leading to a completely new type of measurement on the red planet, Murdoch said. It’s the first time an instrument has been able to quantify lofted dust on Mars.
Images and other data sent back by the rover also confirmed what happened. When the researchers pieced all of the elements collected by the rover together, they determined that the dust devil reached more than 387 feet (118 meters) tall and spanned 82 feet (25 meters wide) – about 10 times larger than the rover itself. While this sounds like a massive whirlwind, it’s the average size for Martian dust devils, Murdoch said.
The researchers were surprised to discover that dust accumulated inside the dust devil, rather than just being carried inside the outer walls – possible because the dust devil may still have been in the process of forming as it moved over Perseverance.