spaceSpace and PhysicsspaceAstronomy

Perseverance's Wind Sensor Damaged By Pebbles Flung By The Wind

Don't worry, Percy lives to give the wind a speeding ticket another day.


Katy Evans

Katy is Managing Editor at IFLScience where she oversees editorial content from News articles to Features, and even occasionally writes some.

Managing Editor

Perseverance snaps a selfie on Mars
Perseverance's selfie game is strong. Image credit: NASA/JPL-Caltech/MSSS

Perseverance has been doing great PR for Mars ever since it arrived last year. How does the Red Planet thank it? By flinging pebbles at one of its instruments for measuring the Martian wind. The culprit thought to have thrown the rocks? The Martian wind itself.

Among the many awesome scientific tools Percy took with it to study conditions on Mars is a weather station known as the Mars Environmental Dynamics Analyzer (MEDA). The instrument measures both wind speeds and direction among other things (humidity, air temperatures, and radiation).


Pebbles carried by some strong gusts recently hit and damaged one of the wind sensors, reports Luckily MEDA can still track the wind, just at a slightly decreased sensitivity.

"Right now, the sensor is diminished in its capabilities, but it still provides speed and direction magnitudes," Rodriguez Manfredi, a scientist at the Spanish Astrobiology Center which runs MEDA, told Elizabeth Howell at "The whole team is now re-tuning the retrieval procedure to get more accuracy from the undamaged detector readings."

Though the team expected wind and dust devils, both having been documented on Mars before, they were not expecting the level of activity from both that Perseverance has experienced in the Jezero Crater. 

"We did not expect so much dust and wind activity. Neither the models nor our experience in other Martian places (where Curiosity or InSight are) predicted us so many events and of such intensity " José Antonio Rodríguez Manfredi, Principal Investigator of the MEDA instrument said, commenting on a paper the team recently published in Science Advances.


According to the paper, around four vortices passed the rover a day and during a one-hour peak period just after noon, it may be more than one per hour. Percy's cameras revealed at least three times huge gusts of wind picked up clouds of dust called "dust lift events". The largest created a huge cloud that covered about 4 square kilometers (1.5 square miles). 

At least three dust devils whirling across the surface of Mars
Perseverance captures dust devils on Mars on July 20, 2021. Image credit: NASA/JPL-Caltech/SSI

In fact, gusts can get pretty strong on Mars. Some measurements suggest they can reach up to 100 kilometers an hour (62 miles an hour), picking up sand, dust, and small rocks. Despite Mars's incredibly thin atmosphere   just 1 percent of Earth's that would still only feel like a light breeze to humans, according to NASA

To make wind measurements, the MEDA instrument must be exposed to the elements, but a stronger than anticipated gust lifted larger than expected pebbles this time. Rodriguez Manfredi told it was ironic that the sensors were damaged "precisely by what we went looking for."

However, the MEDA still works and Perseverance is no stranger to Martian pebbles, it's been carrying one around in its wheel since February.


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