NASA's InSight lander detected a meteoroid impact on Mars

This may be InSight's last big accomplishment before it shuts down.

NASA/JPL-Caltech/University of Arizona

NASA's InSight lander may have had its last hurrah. Researchers have learned that a marsquake the lander detected in Mars' Amazonis Planitia region on December 24th, 2021 was actually a meteoroid impact — the first time any mission has witnessed a crater forming on the planet. Scientists found out when they looked at before-and-after pictures from the Mars Reconnaissance Orbiter (MRO) revealing a 492-foot gash in the landscape.

The meteoroid is believed to have been somewhere between 16 and 39 feet long. It would have burned up in Earth's skies, but it was large enough to survive Mars' extra-thin atmosphere. The impact was violent, digging a hole 70 feet deep and tossing debris as far as 23 miles away from the crater. It also exposed subsurface ice that hasn't been seen so close to the martian equator before now. A sound adaptation of Insight's data (below) shows just how "loud" the event was compared to Mars' regular activity.

It took some time to confirm the event. A Malin Space Science Systems team used two of the MRO's cameras (the black-and-white Context Camera and the Mars Color Imager) to spot the crater in February. Pictures from the color camera helped narrow down the impact to a 24-hour window.

Separately, a group has suggested that 20 of InSight's roughly 1,300 detected marsquakes may be signs of magma. As Gizmodo explains, the quakes' spectral signature hints at a comparatively soft crust in Mars' Cerberus Fossae region. Combined with dark dust, this hints that volcanic activity might have occurred on the planet within the past 50,000 years.

The discovery could help the scientific community understand Mars' geologic timeline by defining the rate of craters appearing on the planet. It might also prove crucial to Mars colonists and explorers who may need the underground ice for sustenance and rocket fuel. Human visitors could carry fewer supplies, or extend their stays.

There's a bittersweetness to this news. NASA previously warned that InSight couldn't last much longer, and now expects the lander to shut down in six weeks as accumulating dust limits the effectiveness of its solar panels. That's better than the end-of-summer cutoff the agency predicted this spring, but it could leave the meteorite detection as InSight's last major accomplishment.