Perseverance rover captures sound of Ingenuity flying on Mars

NASA'sPerseveranceroverhas for the first time captured the low-pitched whirring of theIngenuityhelicopter's blades as it flies through the rarefied Martian atmosphere.

The space agencyonFriday released new footage shot by the six-wheeled robot of its rotorcraft companion making its fourth flightonApril 30 -- this time accompanied by an audio track.

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The nearly three-minute-long video begins with the low rumble of wind blowing across the Jezero Crater, wherePerseverancelanded in Februaryona mission to search for signs of ancient microbes.

Ingenuitytakes off, and its blades can be heard humming softly as they spin at nearly 2,400 rpmonthe 872-foot (262-meter) roundtrip.

The mission's engineers weren't sure they would pick up the flightsoundat all, given thatPerseverancewas parked 262 feet (80 meters) away from the takeoff and landing spot.

The Martian atmosphere is about one percent the density of our planet's, making everything much quieter thanonEarth.

"This is a very good surprise," said David Mimoun, a professor of planetary science at Institut Superieur de l'Aeronautique et de l'Espace (ISAE-SUPAERO) in Toulouse, France, and science lead for the SuperCamMarsmicrophone.

"We had carried out tests and simulations that told us the microphone would barely pick up the sounds of the helicopter, as theMarsatmosphere damps thesoundpropagation strongly," he added.

The SuperCam is an instrumentonboardPerseverancethat laser-zaps rocks from a distance, in order to study their vapor with a device called a spectrometer that reveals their chemical composition.

It also comes with a microphone to record the sounds, which yields additional insights into the physical properties of the targets, like how hard they are.

Similarly, explained Mimoun, the new recording ofIngenuity's flight "will be a gold mine for our understanding of the Martian atmosphere."

Apart from having a lower volume, sounds emittedonMarstravel slower than they doonEarth, because of cold temperatures, which average -81 degrees Fahrenheit (-63 degrees Celsius)onthe surface.

The speed ofsoundonthe planet is therefore around 540 mph (roughly 240 meters per second), compared to about 760 mph (roughly 340 meters per second) here.

The atmosphere ofMars, made up of 96 percent carbon dioxide, tends to absorb higher-pitched sounds, so only lower-pitched sounds can travel long distances.

NASA enhanced the audio, which was recorded in mono, by isolating the pitch of the helicopter blades at 84 hertz, and reducing audio at frequencies below 80 and above 90 hertz. They then increased the volume of the remaining signal.

Soren Madsen,Perseverancepayload development manager at NASA's Jet Propulsion Laboratory, said the recording was an example of how the mission's instruments are able to work in tandem to enhance our understanding of the Red Planet.

AsIngenuitymoves away fromPerseveranceand out of shot, the pitch decreases and as it returns the pitch increases.

This is known as the Doppler effect, and it provides an additional layer of confirmation of the helicopter's flight path when it is out of visual range.

Ingenuitymade the first powered, controlled flightonanother planetonApril 19, and flew a fifth timeonFriday at 3:26 pm Eastern Time (1926 GMT).

After receiving telemetry data several hours later, NASA confirmed the flight's successonTwitter, posting a new picture of the chopper taken fromPerseverance.

Friday's sortie wasIngenuity's first one-way trip, setting the stage for it to begin a new job asPerseverance's scout.

The next phase extends the rotocraft's mission beyond the original month-long technology demonstration. Now, the goal is to assess how well flyers can help future exploration ofMarsand other worlds.

The four pound (1.8 kilogram) mini-chopper was given this assignment after proving itself more robust than its engineers had anticipated.

Perseverance's science team also decided they wanted to stay in the immediate surroundings longer than they first thought, making it possible for the two robots to work together.

The type of reconnaissanceIngenuityperforms could one day also prove useful to human missions, by scoping out the best paths for explorers to traverse, and reaching locations that aren't otherwise possible.