Scientists in Germany spent two years trying to get their heat probe, dubbed the mole, to drill into the Martian crust. But the 16-inch-long (40-centimetre) device that is part of NASA's InSight lander couldn't gain enough friction in the red dirt. It was supposed to bury 16 feet (5 metres) into Mars, but only drilled down a couple of feet (about a half metre). 

Following one last unsuccessful attempt to hammer itself down over the weekend with 500 strokes, the team called it quits on Thursday. 

"We've given it everything we've got, but Mars and our heroic mole remain incompatible," said the German Space Agency's Tilman Spohn, the lead scientist for the experiment. 

The effort will benefit future excavation efforts at Mars, he added in a statement. Astronauts one day may need to dig into Mars, according to NASA, in search of frozen water for drinking or making fuel, or signs of past microscopic life. 

The mole's design was based on Martian soil examined by previous spacecraft. That turned out nothing like the clumpy dirt encountered this time. 

InSight's French seismometer, meanwhile, has recorded nearly 500 Marsquakes, while the lander's weather station is providing daily reports. On Tuesday, the high was 17 degrees Fahrenheit (minus 8 degrees Celsius) and the low was minus 56 degrees Fahrenheit (minus 49 degrees Celsius) at Mars'' Elysium Planitia, an equatorial plain. 

The lander recently was granted a two-year extension for scientific work, now lasting until the end of 2022. 

InSight landed on Mars in November 2018. It will be joined by NASA's newest rover, Perseverance, which will attempt a touchdown on Feb. 18. The Curiosity rover has been roaming Mars since 2012.