Tracking down a new meteorite crater on Mars has revealed a potential new resource that could be crucial to NASA's plans for future human exploration of the Red Planet.
Last Christmas eve, NASA received a special present from space. A small asteroid slammed into the surface of Mars on December 24, 2021. It impacted in a wide flat region of the planet named Amazonis Planitia, located just to the west of the immense Martian volcano, Olympus Mons.
No spacecraft or surface mission witnessed the actual impact as it happened. However, NASA's InSight lander, a few thousand kilometres away, picked up the seismic waves that radiated out from the impact site. The lander's sensitive SEIS instrument (Seismic Experiment for Interior Structure) registered the temblor as one of the largest marsquakes it had detected so far.
At the time, the science team didn't know that it was a meteorite impact.
However, the next time NASA's Mars Reconnaissance Orbiter flew over where the marsquake originated from, the images it sent back managed to capture the fresh crater the space rock blasted into the surface.
These two images from MRO's Context Camera show before-and-after views of the location of the meteorite impact on Dec. 24, 2021, in a region of Mars called Amazonis Planitia. Credit: NASA/JPL-Caltech/MSSS.
The crater was measured at around 150 metres wide and more than 20 metres deep! That apparently makes it the largest fresh crater ever imaged by MRO in the 16 years it has been orbiting Mars!
The meteoroid that formed the crater is estimated at being between 5 to 12 metres across. Such a space rock would have shattered in Earth's atmosphere, possibly scattering meteorites across the surface. However, Mars' very thin atmosphere posed almost no obstacle to it. Thus, it slammed into the ground at almost full-force.
Even more remarkable than the crater itself is what MRO's images picked up surrounding it.
This close-up view of the crater that formed on Dec. 24, 2021 was taken by the High-Resolution Imaging Science Experiment (HiRISE camera) aboard NASA’s Mars Reconnaissance Orbiter. Boulder-size blocks of water ice can be seen around the rim of the impact crater. Credit: NASA/JPL-Caltech/University of Arizona
In the image shown above, bright white and blue regions stand out against the dusty surface of Amazonis Planitia. Those are wide patches and boulder-sized blocks of water ice, excavated from under the surface by the force of the impact.
"The image of the impact was unlike any I had seen before, with the massive crater, the exposed ice, and the dramatic blast zone preserved in the Martian dust," Liliya Posiolova, the lead author of the study that located the crater, said in a NASA press release. Posiolova leads the Orbital Science and Operations Group at Malin Space Science Systems. "I couldn’t help but imagine what it must have been like to witness the impact, the atmospheric blast, and debris ejected miles downrange."
This is apparently the first time we have seen such a deposit of water ice so close to Mars' equator.
"Subsurface ice will be a vital resource for astronauts, who could use it for a variety of needs, including drinking water, agriculture, and rocket propellant," NASA said. "Buried ice has never been spotted this close to the Martian equator, which, as the warmest part of Mars, is an appealing location for astronauts."
Author's note: In the video that leads off this story, NASA details another meteorite impact on Mars, detected in early September, 2021. According to a report by the space agency last month, this was the first seismic event recorded by InSight confirmed to be from a meteoroid impact. The data examined for this discovery also led to the discovery of three other impacts from InSight's records, on May 27, 2020, Feb 18, 2021 and Aug 31, 2021.