Updated at 11 a.m. PST (2 p.m. EST) on March 7: The temperatures in the fourth paragraph have been edited for accuracy.
NASA's Mars InSight lander has a probe designed to dig up to 16 feet (5 meters) below the surface and measure heat coming from inside the planet. After beginning to hammer itself into the soil on Thursday, Feb. 28, the 16-inch-long (40-centimeter-long) probe - part of an instrument called the Heat and Physical Properties Package, or HP3 - got about three-fourths of the way out of its housing structure before stopping. No significant progress was seen after a second bout of hammering on Saturday, March 2. Data suggests the probe, known as a "mole," is at a 15-degree tilt.
Scientists suspect it hit a rock or some gravel. The team had hoped there would be relatively few rocks below ground, given how few appear on the surface beside the lander. Even so, the mole was designed to push small rocks aside or wend its way around them. The instrument, which was provided for InSight by the German Aerospace Center (DLR), did so repeatedly during testing before InSight launched.
"The team has decided to pause the hammering for now to allow the situation to be analyzed more closely and jointly come up with strategies for overcoming the obstacle," HP3 Principal Investigator Tilman Spohn of DLR wrote in a blog post. He added that the team wants to hold off from further hammering for about two weeks.
Data show that the probe itself continues to function as expected: After heating by about 18 degrees Fahrenheit, it measures how quickly that heat dissipates in the soil. This property, known as thermal conductivity, helps calibrate sensors embedded in a tether trailing from the back of the mole. Once the mole is deep enough, these tether sensors can measure Mars' natural heat coming from inside the planet, which is generated by radioactive materials decaying and energy left over from Mars' formation.
The team will be conducting further heating tests this week to measure the thermal conductivity of the upper surface. They will also use a radiometer on InSight's deck to measure temperature changes on the surface. Mars' moon Phobos will pass in front of the Sun several times this week; like a cloud passing overhead, the eclipse will darken and cool the ground around InSight.
For more details, visit DLR's blog:
For more information about InSight, visit:
News Media ContactAndrew Good
Jet Propulsion Laboratory, Pasadena, Calif.