Acoustic measurements of the wind velocity at the Venera 13 and Venera 14 landing sites

It is believed that the results from the missions will be interpreted as wind noise picked up by the microphones. The Groza 2 experiment aboard the landing craft comprised a microphone and appropriate electronic circuitry for measuring acoustic noise both along the descent path and on the surface of the planet. The electromagnet-type microphone remained operational at temperatures up to 800 K and pressures up to 100 bar. The microphone accommodated a 2-kHz frequency band, from 400 to 2500 Hz, with peak sensitivity near 1700 Hz (under standard conditions). By interpreting the acoustic noise on the Venus surface as wind noise in the microphone armature, estimated wind velocities of 0.35-0.57 m/sec are obtained, in good agreement with earlier measurements. It is noted that these values are also consistent with the observed drift of fine soil particles across the surface of the spacecrat landing ring.