Nasa captures sound of chopper blades on Mars

First came the amazing pictures, then the video. Now Nasa is sharing sounds of its little helicopter humming through the thin Martian air.

Nasa's Jet Propulsion Laboratory in California released this first-ever audio on Friday, just before Ingenuity made its fifth test flight, a short one-way trip to a new airfield.

During the fourth flight a week earlier, the low hum from the helicopter blades spinning at more than 2,500 revolutions per minute is barely audible. It almost sounds like a low-pitched, faraway mosquito or other flying insect.

That's because the 1.8-kg helicopter was more than 80 metres from the microphone on the Perseverance rover. The rumbling wind gusts also obscured the chopper's sound. Scientists isolated the sound of the whirring blades and magnified it, making it easier to hear.

"This is a very good surprise," said David Mimoun, a professor of planetary science at Institut Superieur de l'Aeronautique et de l'Espace in Toulouse, France, and science lead for the SuperCam Mars microphone on board Perseverance. "We had carried out tests that told us the microphone would barely pick up the sounds," he added.

Ingenuity, the first powered aircraft to fly at another planet, arrived at Mars on February 18, clinging to Perseverance's belly. Its first flight was April 19. After proving itself more robust, it will now embark on a new mission: to scout ahead of Perseverance to assist in its hunt for ancient life.