The microphone helping NASA understand Mars NASA

THE MICROPHONE HELPING NASA UNDERSTAND MARS

As NASA's Perseverance rover continues to map the surface of Mars, it has for the first time been able to record the "sound environment" of the red planet thanks to a special microphone developed by France's ISAE-SUPAERO.

by Ash Jones

Located on the SuperCam that juts out of the top of the rover, the analysis of the data picked up by the microphone is the latest in over a decade of research by the engineering school helping it to better understand the surfaces of rocky planets.

This marks a milestone in our understanding of other planets and their differences from Earth - a scientific first. The research was published in the Nature journal on April 4, 2022.

The microphone was developed as part of ongoing efforts to better understand Mars in a similar vein to its research into Earth's atmosphere and its interaction with rocky surfaces. It was designed to be able to survive in Mars' harsh climate and was in development for around five years.

Due to the atmospheric differences between Mars and Earth, several differences in how the microphone operates had to be made.

Firstly, the microphone is far smaller and thinner than a microphone any of us would be used to. It is also made up of around 95% CO2 and has to allow for extreme temperature differences.

In essence, the microphone serves three major purposes: to understand the sound associated with the Perseverance's laser impacts on Martian rocks to better understand their properties; to help understand atmospheric phenomena such as wind turbulence, dust devils, and the wind’s interactions with the rover itself; and the sound signature of the rover’s different movements.

Dr Alexander Stott, a postdoctoral researcher at ISAE, revealed that the first sound the team heard was the wind on Mars. "This is great because the wind sounds almost exactly like it does on the Earth," he said. "We measured the sound speed on Mars, the wind at very high frequencies, as well as the attenuation (how sound is lost) of sound with distance."

While you cannot hear sound in the vacuum of space, the atmosphere and surface of planets mean that sound can travel, albeit differently than it does on Earth.

The team reported that the initial analyses of the red planet's atmosphere are "very promising".

David Mimoun, who headed the microphone project, said: "We have, for the first time, high-frequency measurements of the turbulence of the Martian atmosphere, a key parameter in Martian climatology models. "More broadly, the data collected will allow us to do comparative planetology, that is to say, to develop models applicable to the planet Mars, to ultimately better understand its differences with Earth."

While continuing to monitor Mars' atmosphere, ISAE will continue to work with partners to map out other parts of our solar system, with Venus being its likely next destination. n Visit: www.nasa.gov