spaceSpace and Physics

Good News From Mars: After A Rough Start, The Mole Has Started Digging


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockMar 19 2020, 18:59 UTC

The test version of the Mole and Scoop being trialed for the new method. NASA/JPL-Caltech

Given the current climate, it is good to rejoice at the little victories. One of these has arrived all the way from the Red Planet: the Heat Flow and Physical Properties Package (HP3), AKA the "mole", finally appears to be digging into the ground.

The little experiment is a self-hammering probe designed to dig into the ground by moving up and down. The approach is fairly simple – the motion shifts the ground around the mole as it moves further into the ground. Unfortunately, the soil around NASA’s InSight is not like the soil studied at other regions on Mars. Elsewhere the soil is sand-like, but where the mole is located the ground is much harder. 


The HP3 is designed to penetrate up to 5 meters (16 feet) below the surface to measure temperature differences inside the planet and help scientists understand how heat flows on Mars. However, the team's first attempts to dig with the lander did not succeed as the soil stuck together, pushing the mole back. Since it needs friction to be able to move forward, every attempt to widen the hole made it more difficult for the probe.


In October, having spent the summer looking for a solution, the team tried to help the mole by placing the lander's robotic scoop against its side. The objective was to provide enough support for the mole to finally be able to dig. This worked for a while but not enough for the mole to dig deep enough to continue on its journey by itself.

Faced with no simple solution, the team had to think of a desperate method. They used the scoop to hold the back of the mole down and push it into the ground. This was risky as the back of the lander is where the cables and connections are located. However, the latest update shared on Twitter suggests it is working and the mole is moving downward again, hopefully for the next several weeks.


While you might be tempted to think the approach was “if you have a problem, hit it with a shovel”, it was more like "gently nudge it with a scoop until it starts working."

spaceSpace and Physics