NASA’s InSight lander touched down at Elysium Planitia on Mars in late 2018, and it has subsequently made history by taking the first seismic readings on another planet. However, the mission’s burrowing probe was stuck on the surface after the Martian soil proved less receptive than expected. NASA reports its plan of pushing the probe into the surface appears to be working — the instrument is finally below the surface. Its ability to tunnel deeper is unknown, though.
InSight is a stationary lander rather than a rover like Curiosity or Perseverance, but it doesn’t need to go anywhere to do what it went to Mars to do. NASA carefully chose the landing site at Elysium Planitia to perform this important geophysics work. The team deployed InSight’s Seismic Experiment for Interior Structure (SEIS) instrument shortly after landing, allowing the spacecraft to relay data on marsquakes. SEIS just sits on the surface of Mars, so deploying it was straightforward after analyzing the area around the rover. The Heat Flow and Physical Properties Package (HP3) was another story. This “mole” was supposed to dig 16 feet (five meters) into the planet, but it only made it a few inches down before popping back out.
The engineers who designed HP3 had to make some educated guesses about how the Martian soil would behave as it’s so unlike what we have here on Earth. NASA has speculated that the material is so fine that it continuously falls back into the hole each time the probe tries to hammer itself down deeper. After several failed remedies, NASA decided in March to just shove the probe into the surface with the lander’s robotic arm. NASA now says this seems to be working.
After several assists from my robotic arm, the mole appears to be underground. It’s been a real challenge troubleshooting from millions of miles away. We still need to see if the mole can dig on its own. More from our @DLR_en partners: https://t.co/7YjJIF6Asx #SaveTheMole pic.twitter.com/qHtaypoxPp
— NASA InSight (@NASAInSight) June 3, 2020
Over the last several weeks, the arm has slowly applied pressure to help the probe dig deeper. The operation was more delicate than you might expect. The arm had to be carefully placed for each push so it could apply pressure to the instrument without damaging the tether that connects it to the lander. Now, the HP3 has finally disappeared below the surface.
This is a big step in the right direction, but NASA still doesn’t know if the probe will be able to drag itself deeper. If the same issues persist at this depth, there’s nothing on InSight that can reach down there to help it along. Even if the mole is stuck and can’t move deeper, the team has still learned a lot about Mars that could help future instruments reach greater depths.
- InSight Lander Shows Marsquakes Are More Numerous Than Expected
- NASA Puzzled as InSight Drilling Instrument Pops Back Out of Martian Surface
- NASA’s InSight Lander Places the First-Ever Seismic Sensor on Mars