On February 3, 2021, a rock from space slammed into Mars, carving a 21-meter-wide crater and sending seismic waves rippling across the planet. These waves traveled exactly 1,640 kilometers before reaching NASA’s InSight lander, which has been listening to the planet’s rumblings since 2018.

The event sparked a detective story linking meteor impacts and marsquakes, the Martian version of earthquakes. And they’ve done it with the help of artificial intelligence.

These studies show that Mars is bombarded by meteorites far more often than previously thought — about 2.5 times more frequently. It also shows that seismic waves from these impacts can travel faster and deeper through the planet than expected, following what researchers call a “seismic highway” through Mars’ crust and mantle.

A Planet Under Fire

Mars is no stranger to space rock violence. Its proximity to the asteroid belt and thin atmosphere make it a prime target for space debris. While Earth’s thick atmosphere burns up most incoming meteoroids, Mars’ wispy air (its atmosphere is 100 times thinner than Earth’s) offers virtually no protection. For decades, scientists have manually scoured images of the Martian surface, identifying hundreds of new impact craters. But the process is slow and laborious.

But now we have AI. By training AI algorithms to sift through tens of thousands of images from orbiting spacecraft, researchers have dramatically sped up the process. In hours, AI can accomplish what would take humans years. This technological leap has allowed scientists to link seismic data from InSight with fresh craters spotted by cameras like the European Space Agency’s (ESA) Colour and Stereo Surface Imaging System (CaSSIS) and NASA’s Mars Reconnaissance Orbiter.

One such crater, located in the seismically active region of Cerberus Fossae, provided a breakthrough. The 71-foot-wide (21.5-meter) crater was nearly twice as far from InSight as scientists would have predicted based on the quake’s seismic energy. This discrepancy led researchers to realize that the seismic waves had taken a deeper, faster path through Mars’ mantle — a surprising discovery that will likely reshape our understanding of the red planet’s interior.

A Safer Future for Mars Exploration

“Without the seismic data, we would not have known where to look for an impact in the orbital images, and without the orbital images, we would not have been able to locate the source of the seismic energy we detected with InSight,” said Tom Pike, a co-author of the studies and a professor at Imperial College London.

The connection between InSight’s seismic sensors and orbiting cameras will prove useful in the future for studying how different types of acoustic waves travel through Mars. This knowledge can then be leveraged to evaluate the risks posed by meteor impacts to robots, humans, and habitats on the Red Planet.

Also, by studying the frequency and size of impact craters, scientists can piece together the history of water on Mars and assess its potential to have once supported life.

The higher-than-expected impact rate has prompted ESA to accelerate its planetary defense efforts. The agency’s space safety program is actively working to develop technologies to mitigate and prevent the hazards posed by space debris.

The two studies appeared in the Geophysical Research Letters:

• Systematic Identification and Association with 1 InSight Seismic Events (Bickel et al.)
• Unraveling Seismic Propagation Paths through a Cerberus Fossae Impact Detection (Charalambous et al.)