Two NASA spacecraft detect the largest meteorite impacts on Mars

Two NASA spacecraft on Mars—one on the surface and one in orbit—have recorded the largest meteor impacts and impact craters to date.

High-velocity dams last year sent seismic waves rippling thousands of miles across Mars, the first ever detected near the surface of another planet, and carved craters nearly 500 feet (150 meters) wide, scientists reported Thursday in the journal Science.

The larger of the two impacts churned up boulder-sized slabs of ice, which may help researchers find ways for future astronauts to tap into Mars’ natural resources.

The Insight lander measured the seismic tremors, while the Mars Reconnaissance Orbiter provided stunning images of the resulting craters.

Imaging the craters “would already be huge,” but matching them with seismic waves was a plus, said co-author Liliya Posiolova of Malin Space Science Systems in San Diego. “We were so lucky.”

Mars’ atmosphere is thin in contrast to Earth’s, where the thick atmosphere prevents most space rocks from reaching the ground, rather than breaking them up and incinerating them.

A separate study last month linked a recent series of smaller meteor impacts on Mars to smaller craters closer to InSight, using data from the same lander and orbiter.

The impact observations come as InSight nears the end of its mission due to waning power, with its solar panels shrouded in dust storms. InSight landed on Mars’ equatorial plains in 2018 and has since recorded more than 1,300 earthquakes.

“It will be heartbreaking when we finally lose communication with InSight,” said Bruce Banerdt of NASA’s Jet Propulsion Laboratory, the spacecraft’s chief scientist involved in the studies. “But the data it sent us will certainly keep us busy for years to come.”

Banerdt estimated the lander had four to eight more weeks before it ran out of power.

The incoming space rocks were between 16 feet and 40 feet (5 meters and 12 meters) in diameter, Posiolova said. Effects were scored as 4-point magnitudes.

The larger of the two struck last December about 2,200 miles (3,500 kilometers) from InSight, creating a crater about 70 feet (21 meters) deep. The orbiter’s cameras showed debris thrown up to 40 kilometers from the impact, as well as white patches of ice around the crater, the coldest water seen at such low latitudes, Posiolova said.

Posiolova spotted the crater earlier this year after taking additional photos of the area from orbit. The crater was missing from previous photos, and after searching the records, he located the impact in late December. He recalled a large seismic event recorded by InSight at the time, and with the help of that team, matched the fresh hole with what was undoubtedly a meteorite impact. The blast wave was clearly visible.

Scientists also learned that the lander and orbiter teamed up for a previous meteor strike, more than twice the distance of December and slightly shorter.

“Everyone was shocked and surprised. Another one? Yes,” he recalled.

Seismic measurements from the two impacts indicate a denser Martian crust beyond InSight’s position.

“We still have a long way to go to understand the internal structure and dynamics of Mars, which remain largely enigmatic,” said Doyeon Kim of the Institute of Geophysics at ETH Zurich in Switzerland, who participated in the research.

Foreign scientists said future aircraft landings from Europe and China would carry even more advanced seismometers. Future missions will “paint a clearer picture” of how Mars evolved, Yingjie Yang and Xiaofei Chen of the South China University of Science and Technology in Shenzhen wrote in an accompanying paper.

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