NASA’s Perseverance rover carries two microphones which are directly recording sounds on Mars, including wind gusts, rover wheels crunching over gravel, motors whirring as Perseverance moves its arm, and the Ingenuity helicopter.
This artist’s concept depicts NASA’s Mars rover Perseverance on the surface of the Red Planet. Image credit: NASA / JPL-Caltech.
“It’s like you’re really standing there,” said Dr. Baptiste Chide, a planetary scientist at L’Institut de Recherche en Astrophysique et Planétologie.
“Martian sounds have strong bass vibrations, so when you put on headphones, you can really feel it.”
“I think microphones will be an important asset to future Mars and Solar System science.”
Perseverance is the first rover to record Martian sound using dedicated microphones — both of which were commercially available, off-the-shelf devices.
One rides on the side of the rover’s chassis. The second microphone sits on the rover’s mast as a complement to the SuperCam laser instrument’s investigations of rocks and the atmosphere.
SuperCam studies rocks and soil by zapping them with a laser, then analyzing the resulting vapor with a camera.
Because the laser pulses up to hundreds of times per target, opportunities to capture the sound of those zaps quickly add up: the microphone has already recorded more than 25,000 laser shots.
Some of those recordings are teaching scientists about changes in the planet’s atmosphere.
After all, sound travels through vibrations in the air. From its perch on Perseverance’s mast, the SuperCam microphone is ideally located for monitoring microturbulence and complements the rover’s dedicated wind sensors, which are part of the Mars Environmental Dynamics Analyzer (MEDA).
MEDA’s sensors sample the wind’s speed, pressure, and temperature one to two times per second for up to two hours at a time.
SuperCam’s microphone, on the other hand, can provide similar information at a rate of 20,000 times per second over several minutes.
“It’s kind of like comparing a magnifying glass to a microscope with 100 times magnification,” said MEDA’s principal investigator Dr. Jose Rodriguez-Manfredi, a researcher in the Centro de Astrobiología at the Instituto Nacional de Tecnica Aeroespacial.
“From the weather scientist’s point of view, each perspective — detail and context — complements one another.”
The microphone also allows for research on how sound propagates on Mars.
Because the planet’s atmosphere is much less dense than Earth’s, scientists knew higher-pitched sounds in particular would be hard to hear.
In fact, a few scientists were surprised when the microphone picked up the Ingenuity helicopter’s buzzing rotors during its fourth flight, on April 30, 2021 from a distance of 80 m (262 feet).
Information from the helicopter audio enabled researchers to eliminate two of three models developed to anticipate how sound propagates on Mars.
“Sound on Mars carries much farther than we thought,” siad SuperCam scientist Dr. Nina Lanza, a researcher at the Los Alamos National Laboratory.
“It shows you just how important it is to do field science.”
_____
This article is based on text provided by the National Aeronautics and Space Administration.
