A Robot Has Been Stuck on Mars for Months
Specifically on Elysium Planitia, a smooth plain in the planet’s northern hemisphere, where a NASA spacecraft called InSight resides. InSight touched down on the surface last November and used its robotic arm and five-fingered hand to unpack. The cider-colored ground was soon littered with scientific instruments, like a well-arranged picnic spread. Once the spacecraft had settled in by late February, one of the instruments, a probe designed to burrow deep into the Martian ground, started hammering away.
Then, suddenly, it stopped. After traveling 300 million miles to Mars, the probe got stuck just inches below the surface. It has remained wedged there since, but NASA hopes a delicate rescue operation could soon free it.CRP Robotics
“We’d hoped to be well into the ground by now,” Smrekar, the deputy principal investigator of the InSight mission at NASA’s Jet Propulsion Laboratory, told me.
NASA dispatched InSight to Mars to study the interior of the Red Planet, which, even after many decades of missions, scientists still know little about. The mission would help scientists determine what Mars is like on the inside, and whether its guts resemble another rocky planet—our own.The probe, made up of a spike and a sensor-studded tether, is designed to burrow nearly 16 feet into the surface. That’s deeper than previous instruments have gone “on any other planet, moon, or asteroid,” according to NASA (excluding Earth, of course). The tether was supposed to follow the spike down and measure the heat coming from the planet’s interior. The machine only made it 12 inches. “It initially was making fabulous progress, and then just abruptly stopped moving forward,” Smrekar said.
The team was stunned. Maybe the instrument had hit a rock, they thought. The scientists and engineers of the InSight mission had prepared for such a scenario; during testing before launch, the heat probe, which they call “the mole,” had shown it could break some rocks and even maneuver around others. The team instructed the mole to keep hammering, in case the force shattered the obstacle, but that didn’t help.
Scientists now suspect another culprit: the Martian soil itself. As the probe hammered, loose dirt was supposed to swirl around it, providing friction for its back-and-forth movements. But the soil might have clumped together instead and moved away from the instrument. Eventually, a moat of empty space could have emerged between them. “Some friction is essential for the mechanism to work, as the recoil produced by the mechanism during hammering needs to be absorbed,” says Matthias Grott, a scientist at the German Aerospace Center’s Institute of Planetary Research, which provided the instrument to NASA. Without that friction, the probe just bounces in place.