Two NASA spacecraft on Mars — one on the surface and one in orbit — have recorded the largest meteor strikes and craters to date.
Scientists reported Thursday in the journal Science that last year’s high-velocity barrage caused seismic waves that stretched thousands of miles across Mars, the first time they’ve been discovered near the surface of another planet, and drilled craters 500 feet (150 meters) deep.
The two larger hits produced ice sheets the size of boulders, which may help researchers look for ways future astronauts can tap into Mars’ natural resources.
The InSight lander measured the seismic shocks, while the Mars Exploration Rover provided stunning images of the resulting craters.
Imaging the craters “could have been really huge,” said Lilia Pociolova of Malin Space Science Systems in San Diego, and co-author of the study, but matching them with seismic ripples was a bonus. “We were very lucky.”
Mars’ atmosphere is thin unlike Earth, where the dense atmosphere prevents most space rocks from reaching Earth, instead fracturing and burning them.
A separate study last month linked a recent series of smaller Martian meteorite collisions with smaller craters closer to InSight, using data from the same lander and orbiter.
The collision observations come as Insight nears the end of its mission due to its waning power, its solar panels covered in dust storms. InSight landed on the tropical plains of Mars in 2018 and has since recorded more than 1,300 earthquakes.
“It will be heartbreaking when we finally lose contact with Insight,” said Bruce Banerdt of NASA’s Jet Propulsion Laboratory, the lead probe scientist who was involved in the studies. “But the data you sent us will certainly keep us busy for years to come.”
Bannerdt estimated that the probe had another four to eight weeks before it ran out of electricity.
The incoming space rocks are between 16 feet and 40 feet (5 meters and 12 meters) in diameter, Busiulova said. Effects were recorded around size 4.
The two largest rockets struck last December about 2,200 miles (3,500 kilometers) from Insight, leaving a crater nearly 70 feet (21 meters) deep. The orbiter’s cameras showed debris that fell within 25 miles (40 kilometers) of the impact, as well as white patches of ice around the crater, Pociulova said, the most frigid water observed at low latitudes.
Busiulova spotted the crater earlier this year after taking additional photos of the area from orbit. The crater was missing from previous photos, and after examining the archive, I identified the impact as late as December. I remembered a major seismic event that InSight had recorded at the time and with the help of this team, matched the new crater with what was undoubtedly a meteorite strike. The blast wave was clearly visible.
Seismic readings from the two collisions indicate a denser Martian crust outside the InSight site.
“We still have a long way to go to understand the internal structure and dynamics of Mars, which remains largely a mystery,” said Doyeon Kim of the ETH Zurich Institute of Geophysics in Switzerland, who was part of the research.
Scientists from abroad have said that future landers from Europe and China will carry more advanced seismographs. 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 editorial.
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