Mars meteor strike reveals water resources as InSight’s power declines

Some four years after first landing, InSight has seen its power drastically decline in recent months due to dust settling on its solar panels. The spacecraft now is expected to shut down within the next six weeks, bringing the mission’s science to an end.

But until its eventual demise, the probe is still making discoveries, including what led to a large quake that occurred in December last year.

The quake, which is now thought to be have been caused by a meteoroid, was showed to have surface waves – a kind of seismic wave that ripples along the top of a planet’s crust. Nasa scientists have used the big impact and resulting waves to study the structure of Mars’ crust.

The meteoroid is estimated to have spanned 5 to 12 metres – small enough that it would have burned up in Earth’s atmosphere, but not in Mars’ thin atmosphere, which is just 1 per cent as dense as our planet’s.

InSight is studying the planet’s crust, mantle, and core. Seismic waves are key to the mission and have revealed the size, depth, and composition of Mars’ inner layers.

Establishing the rate at which craters appear on Mars is critical for refining the planet’s geologic timeline.

On older surfaces, such as those of Mars and our Moon, there are more craters than on Earth. On our planet, the processes of erosion and plate tectonics erase older features from the surface.

New craters also expose materials below the surface. In this case, large chunks of ice scattered by the impact were viewed by the High-Resolution Imaging Science Experiment (HiRISE) colour camera, which is orbiting Mars to study the planet’s surface from space.

“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,” said Liliya Posiolova, who leads the Orbital Science and Operations Group at Malin Space Science Systems, which has developed equipment for Mars landers.

“I couldn’t help but imagine what it must have been like to witness the impact, the atmospheric blast, and debris ejected miles downrange.”

Subsurface ice will be a vital resource for future astronauts, who could use it for a variety of needs, including drinking water, agriculture, and rocket propellant. 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.

Since landing in November 2018, InSight has detected 1,318 marsquakes, including several caused by smaller meteoroid impacts.

With images and seismic data documenting the event, this is believed to be one of the largest craters ever witnessed forming in any place in the solar system. Many larger craters exist on the Red Planet, but they are significantly older and predate any Mars mission.

“It’s unprecedented to find a fresh impact of this size,” said Ingrid Daubar of Brown University, who leads InSight’s Impact Science Working Group. “It’s an exciting moment in geologic history, and we got to witness it.”