WASHINGTON — Engineers are continuing to work to free an instrument on NASA’s InSight Mars lander that remains stuck just below the surface.
The Heat Flow and Physical Properties Probe (HP3), one of the two main instruments on the spacecraft, features a probe, or “mole,” designed to hammer its way into the surface to a depth of about five meters. Once in place, it will measure how much heat is flowing out of the planet’s interior.
The instrument, placed on the surface weeks after the spacecraft’s landing last November, started the hammering process in late February, but project scientists stopped that work days later when it appeared the mole was stuck about 30 centimeters below the surface. Engineers have since been trying to determine why the mole is stuck and how to get it moving again.
The instrument team identified three potential causes for the mole becoming stuck. The mole may have hit a rock that blocks its progress. The tether trailing behind the mole could be stuck in the instrument’s support structure. Another possibility is that the mole’s hull doesn’t have enough friction with the surrounding regolith to keep it from rebounding when fires its hammer.
That third explanation ...