NASA's InSight lander can finally dig a hole for its Mars heat probe

It made virtually no progress until the robot arm pitched in.

NASA's InSight lander was supposed be digging a hole so a probe (above) could measure the heat escaping from Mars' interior, but it hasn't made much progress since work got started in February -- it hadn't even finished burying itself. At last, it's making some headway. The agency has revealed that the probe, nicknamed "the mole," is finally digging in earnest thanks to a new strategy. The arm had been stymied by unusually rough soil, but the team found it could get the necessary friction by having InSight press its robotic arm against the probe.

It's still moving slowly. The mole has dug roughly three quarters of an inch since October 8th, and it could venture as deep as 16 feet. It could be a long, long time before the probe reaches its potential. Nonetheless, it's a huge relief to scientists worried that one of InSight's key instruments might go to waste. So long as there aren't rocks or other hard obstacles underneath, the probe could shed more light on what's happening beneath Mars' surface.