Time Has Run Out for InSight to Bury Its Heat Probe
In this artist’s concept of NASA’s InSight Lander on Mars, layers of the planet’s subsurface can be seen below and dust devils in the background. IPGP / Nicolas Sarter
Poor little InSight lander. The NASA researcher on Mars tried for almost two years to bury his heat probe in the uncooperative Martian soil, which had a slightly different friction than expected. After trying to make corrections of all kinds, NASA has now announced that it will no longer bury the probe and make it operational.
But it’s not all bad news for InSight, as the lander’s other instruments work well, collecting fascinating data on Martian weather and the existence of Marsquakes. The mission has recently been extended so the lander will continue operations for an additional two years.
Problems with the thermal probe began in March 2019 when the self-digging part of the probe, known as the mole, stopped its progress in digging into the ground to place the probe below the surface. At first it was thought that the mole might have hit a rock, but later it turned out that the problem was with the soil itself. The mole uses the friction of the soil to dig itself into the ground, but the soil in this particular region has been compacted into a hard form called duracrust. This meant that if the mole tried to dig, it would be pushed back out of the hole.
NASA engineers tried a variety of fixes, including using the lander’s robotic arm to pin the mole down and using the shovel on the end of the arm to push the end of the mole and push it into the ground. It was hoped that these efforts would be successful last October when the mole was successfully buried a few inches below the surface. But no progress has been made since then, and the NASA team is finally calling for an end to attempts to fix the problem.
“We gave everything we got, but Mars and our heroic mole remain incompatible,” said Tilman Spohn, lead researcher on InSight’s HP3 (Heat Flow and Physical Properties Package) instrument, which includes the mole statement. “Fortunately, we’ve learned a lot that will benefit future missions that try to dig underground.”
Although there have been problems, InSight has made remarkable discoveries, including learning about Mars quakes and collecting data that has been processed into Martian sounds. As its mission progresses, it will act as a weather station along with the two rovers Curiosity and Perseverance to help scientists learn more about the complex Mars weather system.
At the moment, NASA employees are taking on the mole’s challenges. “We are so proud of our team that worked hard to bring InSight’s mole deeper into the planet. It was amazing to see them fix bugs from millions of miles away, “Thomas Zurbuchen, Associate Science Administrator at NASA, said in the statement.
“That’s why we take risks at NASA – we have to push the boundaries of technology to learn what works and what doesn’t. In this sense, we were successful: We learned a lot that will benefit future missions to Mars and elsewhere, and we thank our German partners at DLR [German Aerospace Center] for providing this tool and for their cooperation. “