The burrowing heat flow probe is ready to hammer into Mars.

NASA's InSight lander on Mars doesn't have to sing "If I had a hammer." It's already got one. The lander's heat flow probe, nicknamed the "Mole," is in position on the ground and is ready to burrow into the planet by hammering its way downward.

The German Aerospace Center (DLR) developed the probe, which is set to start operations Tuesday evening. The first digging session could take up to 4 hours. The InSight team expects confirmation of successful hammering by Wednesday morning. 

The Heat Flow and Physical Properties Probe, HP3 for short, acts like a robo-mole by using a self-hammering spike. If it doesn't bump into any serious rocks, it could reach a depth of up to 16 feet (5 meters) while taking the temperature of Mars along the way.

The Mole won't try to burrow the full depth in one go. The first dig is aimed at reaching a little over 27 inches (70 centimeters) below the surface. NASA and DLR hope the Mole will tell us how much heat is flowing from the interior of Mars and what its source is.  

"Although we have tested the Mole extensively and diligently, there is still an uncertainty. This has never been done before on Mars or on another terrestrial planet," said Tilman Spohn, DLR's instrument lead, in a mission logbook entry. 

InSight has already placed a seismometer on the ground to listen for marsquakes. Unleashing the Mole is another big step forward for the lander's science mission.