NASA’s InSight mission is designed to probe the red planet’s internal physical characteristics, including heat emanating from its core and Marsquake vibrations, among other things. One of InSight’s most imperative instruments is the Mole, a device integrated into the mission’s Heat Flow and Physical Properties Package that is designed to dig up to five meters below the surface to gauge subsurface temperature levels.
When engineers designed the Mole, they kept Mars’ loose and sandy surface in mind. They ultimately decided that InSight would land in a boulder-lacking region on the planet’s surface and ‘pound’ the Mole through the loose surface material with a revolving hammer that taps on the Mole’s head approximately once every 3 seconds or so. The concept looked great on paper, but those calculations left some important variables out.
Soon after InSight deployed its Mole, mission scientists quickly learned that the instrument was meeting unexpected resistance underneath the surface. As much as the hammer pounded on the Mole, it wouldn’t burrow any deeper. Initially, mission scientists thought this was due to a lack of friction in the Martian soil, so they used InSight’s robotic arm to apply force to the Mole as the hammer knocked it down.
The aforementioned solution worked well for a while, but upon relieving the arm’s pressure from the Mole, it popped back up out of the surface. Mission scientists are preparing to assess the situation some more before moving on to alternative solutions. If all else fails, NASA will attempt to push down on the top of the Mole with InSight’s robotic arm, a risky procedure that could potentially damage fragile ribbon cables that supply power.