It was not a purpose of the scientific mission but one instrument on the lander, an air pressure sensor, more formally called the Auxiliary Payload Sensor Subsystem, acted like a microphone. Cold winds constantly blow across the wide Martian plains. The wind is estimated to be blowing 10 mph to 15 mph (16 kph to 24 kph). Thomas Pike of Imperial College London said the rumbling is “rather different to anything that we’ve experienced on Earth, and I think it just gives us another way of thinking about how far away we are getting these signals.” The low frequencies are a result of Mars’ thin air density. The instrument will be moved to the Martian surface in the coming weeks but before the team plans to record more wind noise.
The Jet Propulsion Laboratory released audio clips of the alien wind Friday. These are the first sounds from Mars that are detectable by human ears, according to the researchers. The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission are to place a seismometer on the surface of Mars to measure seismic activity and provide accurate 3D models of the planet’s interior and to measure internal heat flow. InSight also measures tectonic activity and meteorite impacts on Mars today. Studying Mars’ interior structure answers key questions about the early formation of rocky planets in our inner solar system – Mercury, Venus, Earth, and Mars – more than 4 billion years ago.