Novel anemometer tracks sound propagation for faster and more precise calculations of wind speed on the red planet
From the journal: The Journal of the Acoustical Society of America
WASHINGTON, Aug. 13, 2024 — Mars has a notoriously inhospitable environment, with temperatures that fluctuate dramatically over the course of a Martian day and average minus 80 degrees Fahrenheit. Its surface is mostly covered in red dust, and the terrain is marked by craters, canyons and volcanoes. And its atmosphere is extremely thin, only about 1% the density of Earth’s.
Needless to say, measuring wind speed on the red planet is challenging. Mars landers have been able to take measurements – some have measured the cooling rate of heated materials as the wind blows over them, others have used cameras to capture “control objects” blowing in the wind. Both anemometric methods have provided valuable insights into the planet’s climate and atmosphere.
However, there is still room for improvement in the area of astronomical equipment, especially given the plans to send astronauts to Mars in the coming years.
In JASA, published by AIP Publishing on behalf of the Acoustical Society of America, researchers from Canada and the United States demonstrated a novel anemometric sound system using a pair of narrow-band piezoelectric transducers to measure the travel time of sound pulses through the Martian air. The study took into account variables such as diffraction effects of the transducers and wind direction.
“By measuring the differences in the time of sound both forward and backward, we can accurately measure the wind in three dimensions,” said author Robert White. “The two main advantages of this method are that it is fast and works well at low speeds.”
The researchers hope to be able to measure wind speeds of up to 100 per second and even speeds as low as 1 cm/s. This is a notable contrast to previous methods that could only register about 1 per second and had difficulty tracking speeds below 50 cm/s.
“By taking fast and accurate measurements, we hope to measure not only the mean winds, but also turbulence and variable winds,” White said. “This is important for understanding atmospheric variables that could be problematic for small vehicles like the Ingenuity helicopter that recently flew on Mars.”
The researchers characterized ultrasonic transducers and sensors over a wide range of temperatures and a narrow range of pressures of carbon dioxide, the main atmospheric gas on Mars. Their selection showed that only small error rates would result from temperature and pressure changes.
“The system we are developing will be 10 times faster and 10 times more accurate than anything that has been used before,” White said. “We hope it will provide more valuable data for future Mars missions and provide useful information about the Martian climate that may also help us better understand the climate of our own planet.”
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For more information:
Wendy Beatty
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301-209-3090
Article title
Modelling and characterisation of gas-coupled ultrasonic transducers at low pressures and temperatures and implications for acoustic anemometry on Mars
Authors
Robert D. White, Rishabh Chaudhary, Zijia Zhao, Luisa Chiesa, Ian Neeson and Don Banfield
Author affiliations
Tufts University, VN Instruments, NASA Ames Research Center
