The German HP³ drilling instrument brought back by NASA’s Insight spacecraft has meanwhile made its way so far into the soil of the Red Planet that it is completely covered by sand. In view of the extremely lengthy procedure used to reach this stage, those responsible have now decided to fill the pit dug in the process with sand to help the robot penetrate further. The procedure is complicated by dust storms that have covered the solar cells of the probe, which is why less electrical power is available, the German Aerospace Center now explained.
Insight had landed on Mars in late 2018. On board it has the German-developed HP³ tool, which looks like a crude nail. It has a built-in hammer and drags a cable behind it that’s loaded with temperature sensors. It’s actually supposed to hammer its way down three to five meters and measure temperatures to within a thousandth of a degree Celsius. From this, it is possible to determine how the interior of the Red Planet has developed and whether it still has a bright, liquid core. But after the first hammer blows in March 2019, things soon went nowhere, and since then researchers have been trying to solve the unexpected problems the instrument encounters as it penetrates the ground.
By last fall, researchers had changed approaches and placed Insight’s robotic arm behind HP³ as a resistor. In a lengthy process of painstaking work, the instrument has thus succeeded in getting so far into the ground that it is now completely covered by sand, even though it is apparently no more than a centimeter deep, as DLR writes. A thermal conductivity metric will now be used to try to determine depth. Depending on that outcome, researchers then plan to fill in the small pit with the robotic arm to help HP³ dig in further. But that will now take quite a while, they write. HP³ would therefore not carry out new hammer blows until the beginning of 2021.
While the work with HP³ (Heat Flow and Physical Properties Package) is progressing slowly and testing the patience of researchers, other Insight instruments have already found out some things. In the spring, scientists made public that the probe had measured a magnetic field locally that is ten times stronger than expected and also changes depending on the time of day. In addition, numerous earthquakes have been recorded, which, unlike on Earth, are not due to plate tectonics but to volcanic activity.