On its 1,000th sol on the Red Planet, NASA’s InSight Mars lander recorded one of the strongest and longest marsquakes detected yet. The event, which occurred on September 18, had a magnitude of 4.2 and shook the ground for nearly 90 minutes. This is the third strong quake recorded in less than a month, with two more detected on August 25 with magnitudes of 4.2 and 4.1. The detections nearly didn't happen at all due to more than a little dust.
The latest quake is over five times stronger than the previous record-holder detected by InSight in 2019, which came from a region known as Cerberus Fossae roughly 1,600 kilometers (1,000 miles) away, where almost all the quakes have been detected from so far. Details of the September marsquake are still being studied, but the 4.2 magnitude event from August 25 came from further afield. Although its location and direction have not been confirmed, the researchers know that it traveled around 8,500 kilometers (5,280 miles). The magnitude 4.1 quake was also much closer to the lander. It originated just 925 kilometers (575 miles) away.
These new detections are a dream come true for planetary scientists. Just a few months ago, researchers revealed the interior of Mars for the first time using InSight's seismometers, but something still on the scientists' wishlist was stronger quakes from different places on the planet. It looks like Christmas came early on Mars. Except it nearly didn't happen.
Earlier in the year, as Mars's elliptical orbit took it further from the Sun, lower temperatures meant the lander had to rely on its own heaters to stay functioning. On top of that, dust had piled up on its solar panels. The mission expected the Martian wind to clean the panels, but they didn’t get much this year, and the power on the lander started dropping. To conserve energy, it shut down some of its instruments. However, the team on Earth had a pretty clever idea for how to clean the solar panels and keep the light on for the seismometer.
Without the real wind, the team had to make their own. They used the robotic arm on InSight to pour sand near the solar panel, which was enough to sweep off the dust, cleaning the panels and providing enough juice to keep the experiment running.
“If we hadn’t acted quickly earlier this year, we might have missed out on some great science,” InSight’s principal investigator, Bruce Banerdt of NASA’s Jet Propulsion Laboratory, said in a statement. “Even after more than two years, Mars seems to have given us something new with these two quakes, which have unique characteristics.”
Mars is reaching the conjunction meaning that it’s on the opposite side of the Sun with respect to Earth, which means we can’t talk to our robotic explorers due to solar radiation messing with the radio signals. The team will stop issuing commands on September 29 but afterward they plan to do more dust cleaning to boost up the power, and as Mars is approaching the Sun again the power should juice back up.
Even without remote supervision, the seismometer will continue to keep an ear to the ground for potential new quakes.