Engineers have hit pause on attempts make the Mars InSight lander’s self-hammering mole dig into the red planet as boffins admit “the task is not likely to become easier.”
The “mole”, a probe that is part of an instrument on the lander called the Heat Flow and Physical Properties Package (HP3), is supposed to dig down at least three metres into the planet and capture accurate temperature readings of the interior as it does so.
It began its trek early in 2019 and things have not gone well. Rather than the loose soil the mole needs to provide it with friction as it digs, the thing has found itself up against cement-like duricrust. Instead of hammering its way down, the mole has bounced around in place instead.
The latest attempt to help the mole on its way has seen the InSight lander use its robotic arm and scoop to push down on the end cap. One of the challenges with this “helping hand” approach is that it is difficult for the team to judge what the mole is actually doing.
Alas, after some initially hopeful signs that perhaps the mole might be able to “dig on its own”, the team now reckons the thing is still struggling, and noted debris moving in InSight’s scoop, indicating the mole is likely tapping on the underside of the dipper.
“This result of the ‘Free Mole Test’ was, of course, not quite what we had hoped for, but we cannot say that it came as a complete surprise,” commented the Instrument Lead, Tilman Spohn.
Spohn went on to explain that the next course of action was to remove the scoop and see just what had happened in the “pit” and how deep the mole really was.
The next step (due in August) might see the team attempt to fill in the pit around the mole, which Spohn said “will not be an easy task and may take quite some time.” Earlier estimates put the sand required as 300 cubic centimetres, likely needing a number of scrapes of the ground around InSight by its scoop.
While boffins ponder the travails of the mole, the InSight team has plans for the lander’s robot arm. The arm will be used to examine the lander’s solar panels, something engineers have not done since July 2019, as well as to spot meteors in the sky. Scientists hope to use the observations, combined with data from InSight’s seismometer, to detect meteor impacts. ®