lundi 24 avril 2023, par Baptiste CHILDE (Los Alamos National Laboratory)
Jeudi 4 mai 2023 à 11h00 , Lieu : Salle de confĂ©rence du bâtiment 17
On February 18, 2021, NASA’s Perseverance rover landed in Jezero Crater carrying the two first microphones operating on the surface of Mars : the Supercam microphone, positioned on top of the rotating rover’s mast and the EDL microphone fixed on the body of the rover. Working flawlessly since then, they provide the first characterization of Mars’ acoustic environment in the audible range and beyond, from 20 Hz to 50 kHz. Detected sounds originate from three main sources : the atmosphere (turbulence, wind), the shock-waves generated by the Supercam laser ablating rocks, and mission-induced artificial sounds such as the signal generated by the high-speed rotating blades of the Ingenuity helicopter.
After one Martian year, the Perseverance playlist features more than 12 hours of Martian sounds. In addition to provide an unprecedented short timescale characterization of the wind, temperature fluctuations, and the turbulence dissipative regime, this dataset highlights the unique sound propagation properties of the low-pressure CO2-dominated Mars atmosphere : acoustic impedance varying with the season, large intrinsic attenuation of the high frequencies, and the dispersion of the sound speed in the audible range. This presentation will review these results to date and extend them to the exploration of the acoustic environment in our Solar system.
