NASA’s InSight lander touched down successfully on Mars’ Elysium Planitia back in November. A space-faring science laboratory, the lander boasts a five-fingered robotic arm that carefully unpacked a suite of instruments designed to study the inner-workings of The Red Planet.
Part of that suite is a probe designed to dig deep into the Martian crust. While the rollout of the InSight instruments went smoothly, not long after the probe began burrowing into the rusty dirt, something went wrong.
The probe consists of a spike and a sensor-laden tether. Its mission was to delve down 16 feet below the surface and measure the heat coming from Mars’ interior. But after the probe made it about a foot, it stopped.
“It initially was making fabulous progress, and then just abruptly stopped moving forward,” Deputy Principal Investigator of the InSight mission at NASA’s Jet Propulsion Laboratory, Sue Smrekar, told The Atlantic.
Smrekar and the JPL team’s first thought was that the probe, which they dubbed “the mole,” hit a rock. The team had planned for an encounter with a rock. In testing, the mole demonstrated that it could maneuver around rocks or even break through them. So, JPL instructed the probe to hammer away. But the mole was still stuck.
So the team came up with another scenario. As the probe thumps away, loose soil swirls around it, providing friction for its jackhammer-like movements. But perhaps, the team posited, the soil clumped together, leaving space between the soil and instrument.
JPL had not planned for this problem as they didn’t expect to encounter sticky sand on the desert planet. But experiments on Earth using clumpier soil and a replica of the mole showed that this pitfall, so to speak, could be the culprit impeding the probe.
JPL has devised a daring plan to try and get the mole moving again. They can use the robotic arm to add a little dirt into the mole hole. But they need to be able to see it first. To put InSight’s eyes on the problem, they need first to remove the cylindrical case that holds the probe steady.
The probe should have broken free from the case as it drilled down but didn’t make it far enough. Now, the case blocks the team’s view of the mole. So, the team devised a resourceful if not risky plan.
They plan to use InSight’s arm to hoist the case very, very slowly. It’s risky because if they pull the probe out too far, they can’t put it back. InSight’s arm was meant to grasp the case, not the probe itself. So it’s steady as she goes: lift the case, take a picture, analyze it, and, if all is well, lift some more until they get a good view.
This process commences on June 22, with more maneuvers planned for the coming week. While it will be disappointing if the mole can no longer dig, InSight has already made some significant discoveries. Back in April, the lander’s seismometer detected the first-ever Marsquake. The mole is undoubtedly proud of its big sister.