Scientists working with NASA’s Perseverance rover have made a significant discovery during its exploration of Mars’ Jezero Crater. On the mission’s 899th Martian day or sol, the rover captured the lower portion of a Martian dust devil moving along the crater’s western rim. The fascinating video, composed of 21 frames taken four seconds apart and sped up 20 times, was captured by one of the rover’s navigation cameras, Navcams.
It’s the first time any of the rover’s sensors have recorded an encounter with a Martian dust devil, though it is likely not the last. These atmospheric phenomena occur when rising cells of warm air mix with descending columns of cooler air, creating a swirling vortex of dust that can grow much larger than tornadoes on Earth. During peak dust devil season, such as the current summer in the planet’s northern hemisphere, they are commonplace.
The Perseverance rover is cruising through the area, including a delta and igneous rock formations on the edge of Jezero Crater. The vehicle’s instruments zoom in on the rocks’ textures and shapes and use a light that functions as a fancy black light to expose chemicals, minerals, and organic materials to reveal signs of possible life on the planet.
While it is unlikely that Perseverance will see unequivocal evidence of life on Mars, the rover has successfully found sedimentary rocks, which could contain traces of ancient organisms or their chemical remains. However, to confirm a discovery, scientists need to see more examples of these rocks and study their chemistry with more sophisticated instruments back on Earth.
It might take a while before the team has all the rocks they need, but in the meantime, they can sift through all the data Perseverance collected on the mission. That includes sound recordings, air pressure readings, and the detailed images gathered by the rover’s cameras.
For example, in an article published this week in the journal Nature Communications, planetary scientist Naomi Murdoch and her colleagues report on a remarkable discovery: the rover’s camera, Navigation Camera 9, caught a dust devil during its encounter with a rock sample. The dust devil was 2.5 miles away at a location nicknamed Thorofare Ridge and was moving east to west at about 12 mph. Though only the bottom 387 feet of the dust devil was visible in the camera frame, scientists could estimate its full height based on the shadow it cast.
In addition to the visual and spectral data provided by the Navcams, Murdoch’s group also used information from the temperature and air pressure sensors on Perseverance to calculate the size and trajectory of this particular dust devil. This allowed them to work out that it was about 200 feet wide and at least 118 feet tall. The image’s caption is taken from a colorized version of the footage, with the blue rover trajectory indicated by a dashed line and the size estimated by the combination of imaging, modeling, and data from other sensors on the rover.
