AFP, published on Tuesday, May 17, 2022 at 23:54.
After about four years of examining the bowels of the planet Mars, the InSight probe had to end operations this summer due to dust accumulating on its solar panels.
But the data collected will be used over the years by scientists around the world to continue to improve our understanding of planet formation, NASA said in Tuesday’s announcement.
InSight, specially equipped with ultra-sensitive seismometers, recorded more than 1,300 “Mars Earthquakes”, including one of the magnitude 5 quake two weeks ago, the largest to date.
Nice gift before the final blow: sometime in July the seismometers will be turned off. The energy level of the probe will then be checked approximately once a day, and some photos can still be taken. Then the mission will be stopped completely at the end of 2022.
The reason: the accumulation, over months, of Martian dust on two solar panels, each 2.2 meters wide. InSight, already running with only a tenth of the energy it enjoys at the start of each day, will soon run out of battery.
The speed of dust accumulation appears to be more or less in line with what the NASA team had previously predicted.
About a year ago, they did a rather surprising cleanup using their own dust. The robotic arm digs into the ground and gently drops Martian soil on top of the robot. It is therefore partly carried away by the wind on the solar panels, which slightly shed their surface. This technique makes it possible to expand the mission.
Why not have something to wash the panels directly? To questions about costs, Bruce Banerdt, of NASA’s Jet Propulsion Laboratory, answered at a press conference Tuesday. Such a mechanism would indeed violate the budget allocated for scientific instruments.
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InSight, one of four robots currently on the red planet – along with American rover Perseverance and Curiosity, and China’s Zhurong – arrived on Mars in November 2018.
Its seismometers, made in France, have made great progress since then.
Mars’ interior has so far been a “big question mark”, explains Mr. Banerdt, who had been working on this mission for over ten years. But thanks to InSight, “for the first time in history, we can map the interior of Mars.”
Seismic waves, which vary according to the material through which they pass, provide an overview of the planet’s contents.
Scientists can confirm, for example, that the Martian core is indeed liquid, and to determine the thickness of the Martian crust, it is less dense than previously thought and may consist of three layers.
Moreover, a much bigger surprise than all previously recorded in early May. From a size 5, it wouldn’t be huge on Earth, but it appears close to what scientists say they’re most likely to see on Mars.
“This surprise would really be a treasure trove of scientific information if we actually looked at it,” said Bruce Banerdt.
On our planet, earthquakes are mainly caused by plate tectonics, but that’s not all, he explained. The Earth’s crust can move mainly under the influence of temperature deviations caused by the mantle beneath. This is the type of vibration that scientists say they are experiencing on Mars.
The InSight mission also failed: an instrument had to be buried several meters below the surface to measure the planet’s temperature. However, due to the composition of the soil where the robot landed, this “mole” could not sink as expected.
However, given the success of the seismometers, NASA is considering using the technique elsewhere in the future, said Lori Glaze, director of planetary science: “We really wanted to create a complete network on the Moon to really understand what’s going on.”
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