InSight Mars lander waits out dust storm

NASA’s InSight mission, expected to end in the near future, saw a recent drop in power generated by the solar panels as a continent-sized dust storm whirled over Mars’ southern hemisphere. First sighted on Sept. 21, 2022 by NASA’s Mars Reconnaissance Orbiter (MRO), the storm is located about 2,500 miles from InSight and initially had little impact on the lander.

The mission is closely monitoring the lander’s power, which steadily declines as dust builds up on its solar panels. By Monday, October 3, the storm had grown large enough and brought up so much dust that the thickness of the dusty haze in the Martian atmosphere around InSight had increased by nearly 40%. With less sunlight reaching the lander’s panels, its energy dropped from 425 watt-hours per Martian day, or sol, to just 275 watt-hours per sol.

InSight’s seismometer has been in operation on Mars for about 24 hours every other day. But the decline in solar energy does not leave enough energy to fully charge the batteries every sol. At the current rate of discharge, the lander could only operate for a few weeks. To conserve energy, the mission will shut down InSight’s seismometer over the next two weeks.

“We were at the bottom of our ladder when it comes to power. Now we’re on the ground floor,” said InSight’s project manager, Chuck Scott of NASA’s Jet Propulsion Laboratory in Southern California. “If we can fix this, we can keep working through the winter, but I’d be concerned about the next storm coming.”

The team had estimated that InSight’s mission would end sometime between late October this year and January 2023, based on predictions of how much the dust on the solar panels will reduce power generation. The lander has long surpassed its primary mission and is now nearing the end of its expanded mission, performing “bonus science” by measuring marsquakes revealing details about the Red Planet’s deep interior.

Studying Mars storms

There are signs that this large, regional storm has peaked and entered its decay phase: MRO’s Mars Climate Sounder instrument, which measures heating caused by dust absorbing sunlight, sees the storm’s growth slowing. And the dust clouds seen in photos from the orbiter’s Mars Color Imager camera, which creates daily world maps of the Red Planet and was the first instrument to spot the storm, aren’t expanding as quickly as before.

This regional storm is no surprise: It is the third storm of its kind seen this year. In fact, Mars dust storms occur at all times of the Martian year, although more of them — and bigger ones — occur during the northern fall and winter, which is drawing to a close.

Dust storms on Mars are not as violent or dramatic as Hollywood makes them out to be. While winds can blow up to 60 miles per hour (97 kilometers per hour), the air on Mars is thin enough to hold only a fraction of the strength of storms on Earth. Usually the storms are messy: they throw billowing dust high into the atmosphere, which slowly falls back down, sometimes lasting for weeks.

On rare occasions, scientists have seen dust storms evolve into planet-surrounding dust events, covering almost all of Mars. One of these planet-sized dust storms brought an end to NASA’s solar-powered Opportunity rover in 2018.

Because they’re powered by nuclear power, NASA’s Curiosity and Perseverance rovers don’t have to worry about a dust storm depleting their energy. But the solar-powered Ingenuity helicopter has noticed the overall increase in background haze.

In addition to monitoring storms for the safety of NASA missions on the surface of Mars, MRO has spent 17 years collecting invaluable data about how and why these storms form. “We’re trying to capture the patterns of these storms so we can better predict when they’re about to happen,” Zurek said. “We learn more about the Martian atmosphere with each one we observe.”