InSight’s Mole Digs Into Mars
The world’s first-ever interplanetary “mole,” one of the instruments on the InSight mission, began digging into the surface of Mars last night. The mole will be the first robotic instrument to measure the flow of heat on another planet, providing scientists with insights into the formation of the red planet.
“Unlike, say, a camera, which we’ve flown hundreds on various missions, there hasn’t been anything like the mole before,” said Troy Hudson, an instrument systems engineer at NASA’s Jet Propulsion Laboratory (JPL).
The mole, known as the Heat Flow and Physical Properties Probe, was placed on the surface by InSight about two weeks ago. However, the instrument itself has been in use for about 10 years. Notably, NASA’s Curiosity rover, to which the agency recently said goodbye, also drilled into the Martian surface, gathering information about rocks at different sites.
“Getting the mole into the regolith and seeing how it behaves is also going to be exciting from an engineering standpoint, as well as from a science standpoint,” said Sue Smrekar, deputy principal investigator for the InSight mission and a geophysicist at JPL. “It’s just going to be exciting to actually get under the subsurface.”
The ultimate goal for the mole’s mission is to dig itself through the Martian regolith to a depth of five meters. It will leave a trail in the form of a cord with sensors. As the mole does the digging, it sends heat pulses and measures the speeds at which the heat dissipates, providing scientists with the rock-to-air ratio in that specific layer of the surface.
“It’ll help us understand, Is this primarily sand that’s been blown into this crater [or] is it more of a mix of things that you would expect from impact crater ejecta?” Smrekar said, referring to the instrument’s position inside the crater.
At the depth of five meters, the mole will take temperature measurements throughout the Martian year, informing scientists about how heat moves through the planet and potentially giving them clues as to how Mars became Mars in the first place. “Heat is the engine that drives geology,” Hudson said.
Scientists look to two heat sources to learn about the formation of the red planet. “One is the initial heat from accretion — all these rocks are smashing together at enormous velocities, and so you have this initial heat budget,” Smrekar said. The second is radiogenic elements — uranium, thorium, potassium and the like — releasing heat in the crust. “That’s what we’re really expecting to learn the most about, is the concentration of these radiogenic elements,” Smrekar said.
InSight, which landed on Mars last November, does not rely on any human help. The mole had to be programmed by engineers to accomplish its goals. “We are literally breaking ground on a new type of investigation,” Hudson said. “It probably couldn’t do its job as well, at least this particular design, on the moon,” Hudson said.
Once the mole gathers the data on the regolith concentrations and the thickness of the crust, scientists will use models to evaluate different scenarios about the formation of the planet. “Maybe Mars will surprise us,” Smrekar said. “That’s always the most interesting result — when you get something you don’t expect.”
Image Credit: NASA/JPL-Caltech
Learn more on Asgardia.Space
