It never really worked. Martian dirt was found to be unexpectedly prone to clump together, decreasing the kind of friction the mole needs to make its way deeper and deeper. Ground crews recently made a last ditch effort to use InSight’s arm to scoop dirt on the probe to tie it up and provide more friction. After attempting 500 hammer blows on January 9, the team quickly realized that there was no room for improvement.
This is disheartening news, given that NASA recently decided to extend InSight’s mission until December 2022. Meanwhile, there won’t be much of a role for the thermal probe. Bruce Banerdt, InSight’s principal investigator, says the planet’s temperature could still be measured at the surface and a few inches below the surface using some of InSight’s instruments that are still functioning. “This will allow us to determine the thermal conductivity of the nearby surface, which could vary seasonally due to changes in atmospheric pressure,” he says.
And although the mole was unable to accomplish what was expected, it is not correct to view this as a failure. “We encountered new properties of soil that had never been seen before on Mars, with a thick, crisp surface layer that drastically decreases its volume when crushed,” Banerdt explains. “We don’t yet understand everything we’ve seen, but geologists will be looking at this data for years to come, using it to unearth clues about the history of the Martian environment there.
InSight will continue some of its other investigations, in particular the measurement of seismic activity on Mars. It turns out that the Red Planet is constantly shaken by earthquakes.