InSight Mars Lander’s ‘Mole’ Probe Now Completely Underground
NASA’s InSight Lander made history when it became the first mission to take seismic readings on another planet, but the lander’s other major experiment hasn’t been as successful. The mission’s burrowing heat probe, sometimes called the “Mole,” has struggled to even make it underground, but NASA has finally reported success getting it to stay there. The instrument managed to drag itself below the surface and is no longer visible. We don’t yet know if it will work as intended, but this is a big step in the right direction.
After landing on the red planet, InSight sent back images of its surroundings. NASA engineers built a replica of the landing zone to carefully plan the instrument deployment. The Seismic Experiment for Interior Structure (SEIS) was placed on the surface several months later, and it has since sent back a plethora of data on the planet’s internal structure. The Heat Flow and Physical Properties Package (HP3) was supposed to hammer itself into the ground, relying on the friction of soil to help it along. However, the Mole encountered issues almost immediately.
NASA and the German Aerospace Center (DLR), which provided the probe, now believe the unusual stickiness of the soil is responsible for the issues. The Mole is designed to allow loose soil to flow around it, which provides friction as it hammers deeper into the planet. However, the soil at InSight’s landing site clumps together, forming a small pit around the Mole. As a result, the probe just bounces itself out of the hole.
Starting late last year, the InSight team started using the lander’s robotic arm to tamp down the soil around the mole in hopes it would increase friction. Eventually, they just started pushing the Mole with the arm. The Mole has since advanced slowly in a series of brief tunneling operations, aided by the arm scooping soil on top of it to provide increased traction.
NASA now reports that the Mole is fully underground. The team has even moved the arm to ensure that it has completely descended below the surface. There is now hope the Mole will be able to dig down deeper as originally intended. As it burrows, it will drag the tether and its temperature sensors along with it. This will allow scientists to take the planet’s temperature, which was not possible before.
NASA and DLR currently believe the Mole will start hammering away early next year. In the meantime, they plan to dump more Martian soil on top of the probe and pack it down to ensure it doesn’t jump back out of the hole.