Two NASA spacecraft detect the biggest meteor strikes on Mars

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

Last year’s high-velocity dams sent rippling seismic waves thousands of miles across Mars, the first ever detected near the surface of another planet, and carved craters nearly 150 meters in diameter , the scientists reported Thursday in the journal. Science.

The larger of the two strikes produced boulder-sized patches of ice, which could help researchers look for ways for future astronauts to harness Mars’ natural resources.

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

The crater imagery “would already have been huge,” but matching it to the seismic ripples was a bonus, said co-author Liliya Posiolova of Malin Space Science Systems in San Diego. “We were so lucky.”

Mars’ atmosphere is thin unlike Earth’s, where the thick atmosphere prevents most space rocks from reaching the ground, breaking them apart and incinerating them instead.

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

The impact sightings come as InSight nears the end of its mission due to dwindling power, its solar panels blanketed by dust storms. InSight landed on the equatorial plains of Mars in 2018 and has since recorded over 1,300 Marsquakes.

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

Banerdt estimated the lander still had between four and eight weeks before the blackout.

The incoming space rocks were between 16 feet and 40 feet (5 meters and 12 meters) in diameter, Posiolova said. The impacts recorded a magnitude of about 4.

The larger of the two struck last December some 2,200 miles (3,500 kilometers) from InSight, creating a crater about 70 feet (21 meters) deep. Orbiter cameras showed debris thrown up to 40 kilometers from the impact, as well as white patches of ice around the crater, the most frozen 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 scouring the archives, she identified the impact through late December. She remembered a large seismic event recorded by InSight at that time and with the help of that team matched the new hole to what was undoubtedly a meteoroid strike. The shock wave was clearly visible.

Scientists also learned that the lander and orbiter teamed up for an earlier meteoroid strike, more than double the distance of the one in December and slightly smaller.

“Everyone was just shocked and amazed. Another one? Yeah,” she recalled.

Seismic readings from both impacts indicate denser Martian crust beyond InSight’s location.

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

Outside scientists have said that future European and Chinese landers will carry even more advanced seismometers. Future missions will “paint a clearer picture” of the evolution of Mars, Yingjie Yang and Xiaofei Chen of the South China University of Science and Technology in Shenzhen wrote in an accompanying editorial.

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