After being stuck for months, the InSight landers heat probe has managed to dig down a few centimeters into the Martian dirt. Its a positive sign that the probe didnt hit a rock as engineers originally feared and that a newly devised strategy to remedy the situation is actually working.

In this latest test, the heat probe managed to progress about 3 centimeters, which is slightly more than an inch. Thats not a huge distance by any measure, but its a massive leap for the InSight team, which has been grappling with this thorny problem since late February.

Built by the German Aerospace Center (DLR), the Heat Flow and Physical Properties Package (HP3) is designed to measure the heat emanating from beneath the Martian surface. The probe component of HP3, dubbed the mole, was expected to descend down to a depth of around 5 meters (16 feet), but it didnt get any further than 35 centimeters (14 inches) before it simply stopped.

Fears quickly emerged that the mole had struck a rock. If true, that wouldve signified the end of the HP3 mission, as the probe cannot be pulled out and relocated.

This past summer, however, new evidence emerged suggesting the mole hadnt struck a rock but rather some dense material. Invigorated with hope, the InSight team devised a new strategy in an attempt to restore friction between the mole and the ground materiala requirement for the probes forward motion (otherwise the mole just bounces around in place like a pogo stick). To get the needed friction, the team used the InSight landers robotic claw to pin the mole against the wall of the shallow hole.

Excitingly, this strategy appears to be working, according to a tweet put out by the German Aerospace Agency.

Good news from #Mars! Confirmed!, exclaimed the agency in the tweet. After 3 cm progress, it appears the @DLR_de Mole on @NASAInSight was not stopped in its tracks by a rock under the Martian surface but had in fact lost friction.

Looking at the animated video (above), the mole appears to be holding steady in place thanks to the robotic claw, and its clearly progressing downward. It actually looks really great, even if its small process.

A tweet from the NASA InSight account echoed the pronouncement: With an assist from my robotic arm, the mole is digging again! We are just starting this new campaign, and are hopeful we can continue to dig.

Not much more is known beyond these tweets, but an astute commenter asked if the attached cable, which is spinning along with the mole, might pose a problem as the probe gets deeper.

Weve noted the spin, replied DLR. Its roughly 10 per 2cm. In the testbed weve seen a rotation by 270 for 5m. Were watching the present situation w/ care being confident that the rotation will be reduced once tether is in ground. Its expected to act as a fin slowing the rotation down.

So, thats a big phew. The heat probe is a key component of InSights mission to study the interior of Mars, and it would have been extremely disappointing if it had failed altogether. Hopefully these precious few centimeters of progress represent a sign of success to come.

More here:

NASA's Plan to Rescue InSights Stuck Heat Probe Appears to Be Working - Gizmodo