InSight Lander 'Hears' the winds of Mars

NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander, which touched down on Mars just 10 days ago, has provided the first ever "sounds" of Martian winds on the Red Planet. A media teleconference about these sounds was held on December 7 at 12:30 p.m. EST (9:30 a.m. PST).

InSight sensors captured a haunting low rumble caused by vibrations from the wind, estimated to be blowing between 10 to 15 mph (5 to 7 meters a second) on Dec. 1, from northwest to southeast. The winds were consistent with the direction of dust devil streaks in the landing area, which were observed from orbit.

One of two Mars InSight's 7-foot (2.2 meter) wide solar panels was imaged by the lander's Instrument Deployment Camera, which is fixed to the elbow of its robotic arm. Credits: NASA/JPL-Caltech

"Capturing this audio was an unplanned treat," said Bruce Banerdt, InSight principal investigator at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. "But one of the things our mission is dedicated to is measuring motion on Mars, and naturally that includes motion caused by sound waves."

NASA’s media teleconference on the InSight lander and its recordings of wind vibrations on Mars. 

Speakers included:

Bruce Banerdt, InSight Principal Investigator, NASA’s Jet Propulsion Laboratory

Thomas Pike, Short Period Seismometer Science Lead, Imperial College, London

Don Banfield, Auxiliary Payload Sensor Subsystem (APSS) Science Lead, Cornell University

Lori Glaze, Acting Director of Planetary Science, NASA HQ

Two very sensitive sensors on the spacecraft detected these wind vibrations: an air pressure sensor inside the lander and a seismometer sitting on the lander's deck, awaiting deployment by InSight’s robotic arm. The two instruments recorded the wind noise in different ways. The air pressure sensor, part of the Auxiliary Payload Sensor Subsystem (APSS), which will collect meteorological data, recorded these air vibrations directly. The seismometer recorded lander vibrations caused by the wind moving over the spacecraft's solar panels, which are each 7 feet (2.2 meters) in diameter and stick out from the sides of the lander like a giant pair of ears.

This is the only phase of the mission during which the seismometer, called the Seismic Experiment for Interior Structure (SEIS), will be capable of detecting vibrations generated directly by the lander. In a few weeks, it will be placed on the Martian surface by InSight's robotic arm, then covered by a domed shield to protect it from wind and temperature changes. It still will detect the lander's movement, though channeled through the Martian surface. For now, it’s recording vibrational data that scientists later will be able to use to cancel out noise from the lander when SEIS is on the surface, allowing them to detect better actual marsquakes.

This image from InSight's robotic-arm mounted Instrument Deployment Camera shows the instruments on the spacecraft's deck, with the Martian surface of Elysium Planitia in the background. Credit: NASA/JPL-Caltech

When earthquakes occur on Earth, their vibrations, which bounce around inside our planet, make it “ring” similar to how a bell creates sound. InSight will see if tremors, or marsquakes, have a similar effect on Mars. SEIS will detect these vibrations that will tell us about the Red Planet’s deep interior. Scientists hope this will lead to new information on the formation of the planets in our solar system, perhaps even of our own planet.

SEIS, provided by the French Space Agency CNES, includes two sets of seismometers. Those contributed by the French will be used once SEIS is deployed from the deck of the lander. But SEIS also includes short period (SP) silicon sensors developed by Imperial College London with electronics from Oxford University in the United Kingdom. These sensors can work while on the deck of the lander and are capable of detecting vibrations up to frequencies of nearly 50 hertz, at the lower range of human hearing.

The spectrogram of vibrations (frequency spectrum over time) recorded by two of the three sensors of the short period seismometer on NASA’s InSight lander on Mars. This spectrogram shows the first 1,000 seconds, roughly 20 minutes, of InSight’s first seismic data from the Red Planet. The vibrations of the lander are due to the wind passing over the spacecraft, particularly the large solar arrays. The annotation indicates the 20-second raw sound clip played earlier. Credits: NASA/JPL-Caltech/CNES/UKSA/Imperial College London/Oxford

“The InSight lander acts like a giant ear,” said Tom Pike, InSight science team member and sensor designer at Imperial College London. "The solar panels on the lander's sides respond to pressure fluctuations of the wind. It's like InSight is cupping its ears and hearing the Mars wind beating on it. When we looked at the direction of the lander vibrations coming from the solar panels, it matches the expected wind direction at our landing site."

Pike compared the effect to a flag in the wind. As a flag breaks up the wind, it creates oscillations in air pressure that the human ear perceives as flapping. Separately, APSS records changes in pressure directly from the thin Martian air.

An annotated image of the surface of Mars, taken by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter (MRO) on May 30, 2014. The contrast has been enhanced in this image to better show the region where InSight landed on Nov. 26, 2018. The labels show the approximate position of NASA’s InSight lander in Elysium Planitia. Overlaid on top are the direction of the vibrations detected by InSight’s science instruments. The diagonal lines, faintly seen moving from upper left corner to the lower right corner of the image, show the paths of dust devils on the Martian surface. The vibrations recorded by InSight line up with the direction of the dust devil motion. Credits: NASA/JPL-Caltech/University of Arizona/Imperial College London

"That's literally what sound is — changes in air pressure," said Don Banfield InSight's science lead for APSS from Cornell University in Ithaca, New York. "You hear that whenever you speak to someone across the room."

Unlike the vibrations recorded by the short period sensors, audio from APSS is about 10 hertz, below the range of human hearing.

The raw audio sample from the seismometer was released unaltered; a second version was raised two octaves to be more perceptible to the human ear – especially when heard through laptop or mobile speakers. The second audio sample from APSS was sped up by a factor of 100, which shifted it up in frequency.

A copy of one of the sensors on NASA InSight’s seismometer, compared to a 2-euro coin (about 1 inch wide). The short-period seismometer has three of these sensors. Credits: Imperial College London

An even clearer sound from Mars is yet to come. In just a couple years, NASA's Mars 2020 rover is scheduled to land with two microphones on board. The first, provided by JPL, is included specifically to record, for the first time, the sound of a Mars landing. The second is part of the SuperCam and will be able to detect the sound of the instrument's laser as it zaps different materials. This will help identify these materials based on the change in sound frequency.

JPL manages InSight for NASA's Science Mission Directorate in Washington. InSight is part of NASA's Discovery Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space in Denver built the InSight spacecraft, including its cruise stage and lander, and supports spacecraft operations for the mission.

This illustration is a still frame from NASA's Experience InSight app (https://eyes.nasa.gov/insight). It shows in blue outline the location of the pressure sensor inlet, tucked inside the Wind and Thermal Shield. The pressure sensor inlet is part of InSight's Auxiliary Payload Sensor Subsystem. Credits: NASA/JPL-Caltech

This illustration is a frame from NASA's Experience InSight app (https://eyes.nasa.gov/insight) that shows the location of the spacecraft's pressure sensor inlet, after the Wind and Thermal Shield (WTS) has been deployed. (The real InSight spacecraft has not yet deployed its instruments or the WTS.) The pressure sensor inlet is outlined in blue and the WTS (white dome) has been placed over InSight's seismometer on the ground on Mars. The sensor is part of InSight's Auxiliary Payload Sensor Subsystem. Credits: NASA/JPL-Caltech

A number of European partners, including CNES and the German Aerospace Center, support the InSight mission. CNES and the Institut de Physique du Globe de Paris provided SEIS, with significant contributions from the Max Planck Institute for Solar System Research in Germany, the Swiss Institute of Technology in Switzerland, Imperial College and Oxford University in the United Kingdom, and JPL. DLR provided the Heat Flow and Physical Properties Package (HP3) instrument, with significant contributions from the Space Research Center of the Polish Academy of Sciences and Astronika in Poland. Spain’s Centro de Astrobiología supplied the wind sensors.

Los Alamos National Laboratory in New Mexico and Institut de Recherche en Astrophysique et Planétologie in France are responsible for delivering the SuperCam instrument to NASA. The SuperCam microphone is provided by Institut Supérieur de l'Aéronautique et de l'Espace, a French higher education institution.

Panorama of the landing site of the InSight taken at the Sun 10 Credit: NASA / JPL-Caltech / Damia Bouic.

The Sounds:

Sounds from InSight's Pressure Sensor on Mars

More Audible Sounds from InSight's Seismometer on Mars

Raw Sounds from InSight's Seismometer on Mars

Sounds of Mars: NASA's InSight Senses Martian Wind


Source: NASA,