NASA’s InSight lander, with a thin coating of reddish dust seen on the solar panels.
Image: NASA/JPL-Caltech

The InSight lander seems to have been hit by one of Mars’ famous dust devils, but don’t worry—the NASA probe is just fine. If anything, the sudden blast of wind helped to clear off some annoying dust that had been collecting on the probe’s solar panels. The passing wind vortex also produced some cool science.

Measurements gathered by InSight on February 1, 2019 are consistent with a wind vortex, or dust devil, passing directly over the InSight probe, according to a NASA press release. Sadly, InSight’s camera didn’t snap a shot of the dusty, swirling column, but the lander’s two large solar panels experienced sudden power boosts—around 0.7 percent in one and 2.7 percent in the other—which NASA says is exactly the kind of thing you’d expect if a thin layer of dust had suddenly been removed from the surface of the solar panels.

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NASA scientists have seen this sort of thing before. Both the Spirit and Opportunity rovers experienced sudden power boosts, some as high as 10 percent, followed by photographic evidence showing panels with less dust on them than before.

A dust devil spotted by NASA’s Opportunity rover in 2016.
Image: NASA/JPL-Caltech

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What’s unique about this most recent event, however, is that InSight was able to gather other forms of evidence to bolster the case. And in fact, this marks the first time that a dust devil has been directly detected by instruments aboard a Martian probe, according to NASA; none of the space agency’s “solar-powered rovers have included meteorological sensors that record so much round-the-clock data,” noted the space agency in a press release.

The event happened during the early afternoon in Elysium Planitia, a region on the Martian equator. As on Earth, dust devils are more prominent during this time of day owing to the interactions of hot surfaces with cooler air above. Elysium Planitia also happens to be a particularly windy zone on the planet.

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InSight’s Auxiliary Payload Sensor Suite—a series of weather sensors—captured data consistent with a dust devil passing overhead. The wind changed direction by 180 degrees, for example, while the wind speed suddenly jumped to 45 miles per hour (72 kilometers per hour). The APSS also detected a sharp drop in air pressure. Interestingly, NASA said it’s the single largest pressure drop ever recorded by a probe on Mars. The sudden drop of 9 pascals, or 13 percent of the local air pressure, hinted at winds too fast for InSight’s sensors to pick up.

A color-composite image showing track marks left behind by the convergence of hundreds, and possibly thousands, of dust devils on Mars.
Image: ESA/Roscosmos/CaSSIS

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“The absolute fastest wind we’ve directly measured so far from InSight was 63 miles per hour (28 meters per second), so the vortex that lifted dust off our solar panels was among the strongest winds we’ve seen,” explained InSight scientist Aymeric Spiga in the NASA press release. “Without a passing vortex, the winds are more typically between about 4-20 miles per hour (2-10 meters per second), depending on time of day.”

This event is not as exotic as it may sound. Dust devils are a regular fixture on Mars, carving the surface with distinctive patterns. It’s estimated that millions of dust devils form on Mars each day.

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InSight has already detected a bunch of nearby dust devils since it arrived on Mars in late November 2018. NASA suspects this won’t be the last time a wind vortex sweeps over the probe—and that’s a good thing. These whirlwinds aren’t dangerous, and with no one on Mars to clear the dust off InSight’s solar panels, these fortuitous events will have to suffice. NASA engineers would like to capture power boosts comparable to the ones experienced by Opportunity and Spirit—so they’re actively hoping for more powerful vortices.

In addition, ongoing measurements of these events will improve NASA’s ability to design and refine future solar-powered missions, and to figure out how wind affects the Martian surface.

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