This story is part of Welcome to Mars, our series exploring the red planet.

"For the first time, a spacecraft on another planet has recorded the sounds of a separate spacecraft." That's quite a statement NASA dropped on Friday. 

The Perseverance rover on Mars used its audio recording capability to capture the sound of the Ingenuity helicopter in flight across the red planet. What does a helicopter on Mars sound like? A gentle hum.

NASA added the audio to video footage of the rotorcraft's ambitious fourth flight, which took place on April 30.

The rover used a microphone located on its SuperCam laser instrument. The helicopter is audible against a backdrop of Martian wind noises. The audio is all the more remarkable considering the rover was 262 feet (80 meters) away from Ingenuity's takeoff spot at the time. The planet's atmosphere makes it difficult for the sound to carry.

NASA scientists processed the audio to make the rotorcraft easier to hear. "We have been lucky to register the helicopter at such a distance," said SuperCam Mars microphone science lead David Mimoun. "This recording will be a gold mine for our understanding of the Martian atmosphere."  

The Ingenuity technology demonstration has been wildly successful as NASA achieved the first powered, controlled flight on another planet.

Ingenuity's fifth flight -- and its first one-way trip -- is scheduled to happen today, though it takes several hours for data and confirmation of the attempt to come back to Earth. The new soundtrack adds a captivating aural dimension to the historic mission.

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