This illustration depicts NASA’s Perseverance rover operating on the surface of Mars. Credit: NASA
Two microphones aboard the six-wheeled spacecraft add a new dimension to the way scientists and engineers explore the Red Planet.
Thanks to two microphones aboard
This illustration of NASA’s Perseverance Mars rover indicates the location of its two microphones. Credit: NASA/JPL-Caltech
Perseverance is the first spacecraft to record the sound of the Red Planet 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 mic sits on Perseverance’s mast as a complement to the SuperCam laser instrument’s investigations of rocks and the atmosphere.
NASA’s Perseverance Mars rover carries two microphones which are directly recording sounds on the Red Planet, including the Ingenuity helicopter and the rover itself at work. For the very first time, these audio recordings offer a new way to experience the planet. Credit: NASA/
These commercial-grade microphones are similar to one on the chassis of NASA’s Perseverance Mars rover. Credit: Courtesy of DPA
The Era of Space Microphones
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 mic is ideally located for monitoring “microturbulence” – minute shifts in the air – and complements the rover’s dedicated wind sensors, which are part of a suite of atmospheric tools called MEDA, short for the Mars Environmental Dynamics Analyzer.
NASA’s Perseverance Mars rover carries two commercial-grade microphones, including this one on its mast. The mast microphone is part of the SuperCam instrument. Credit: NASA/JPL-Caltech
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, Jose Rodriguez-Manfredi of the Centro de Astrobiología (CAB) at the Instituto Nacional de Tecnica Aeroespacial in Madrid. “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 – unsure if they’d hear anything at all – were surprised when the microphone picked up the Ingenuity helicopter’s buzzing rotors during its fourth flight, on April 30, from a distance of 262 feet (80 meters).
NASA’s Perseverance Mars rover carries two commercial-grade microphones, including this one on its chassis. Credit: NASA/JPL-Caltech
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,” said Nina Lanza, a SuperCam scientist who works with the microphone data at LANL. “It shows you just how important it is to do field science.”
Sound Check
There’s another aspect of space exploration that could benefit from an audio dimension: spacecraft maintenance. Engineers use cameras to monitor the wheel wear on Curiosity rover and dust accumulating on InSight’s solar panels. With microphones, they could also check a spacecraft’s performance the way mechanics might listen to a car engine.
The Perseverance team is amassing loads of recordings from the rover’s chassis mic, which is well-positioned to listen to its wheels and other internal systems. While there aren’t enough recordings yet to detect any changes, over time, engineers may be able to pore over that data and discern subtle differences, like additional electric current going to a particular wheel. This would add to the ways they already monitor the spacecraft’s health.
“We would love to listen to these sounds regularly,” said Vandi Verma, Perseverance’s chief engineer for robotic operations at JPL. “We routinely listen for changes in sound patterns on our test rover here on Earth, which can indicate there’s an issue that needs attention.”
More About the Mission
A key objective for Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith.
Subsequent NASA missions, in cooperation with ESA, would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.
The Mars 2020 Perseverance mission is part of NASA’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.
